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IB Chemistry/Definitions

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IB Chemistry Option Definitions

Topic 1 - Stoichiometry

 * Absolute Zero is zero on the Kelvin scale, 0 K (on the Celsius scale this is -273 °C)
 * Avogadro’s constant:	The number of particles in 12g of 12C.	6.022 x 10^23
 * Atomic mass: The mass of a single atom
 * Chemical reaction:	A reaction in which bonds in the reactants are broken and bonds in the products are formed and vice versa resulting in an energy change between the reacting system and its surroundings.
 * Compound:	Two or more types of atoms chemically bonded together.
 * Concentration: a measure of the amount of dissolved substance contained per unit of volume
 * Element:	An element contains atoms of only one type.
 * Excess:	The reactant which there is more of than needed to react with all of the limiting reagent.
 * Formula, empirical:	The formula obtained by experiment, showing the simplest whole number ratio of atoms of each element in a particle of the substance.
 * Formula mass: The mass of one formula unit of that substance
 * Formula, structural:	Shows the arrangement of atoms and bonds within a molecule.
 * Heterogeneous mixtures: which have a non-uniform compositions and hence their properties vary throughout the mixture.
 * Homogeneous mixtures: which have both uniform composition and uniform properties throughout the mixture.
 * Ion: An atom or molecules where the total number of protons is not equal to the total number of electrons.
 * Limiting reagent:	The reactant which will determine the theoretical maximum amount of product formed.
 * Molar mass:	The mass of a mole of a substance.
 * Mole:	The amount of substance that contains a number of specified species equal to Avogadro’s constant.
 * Molecular mass: the mass of one molecule of that substance
 * Mixture: Physically combined pure substances.
 * Pure substance: A matter that has a constant composition
 * Solute: A substance that is dissolved into another ( the solvent)
 * Solvent: a substance that dissolves another ( the solute)
 * Yield, percentage:	The experimental yield as a percentage of the maximum theoretical yield.
 * Yield:	The amount of product.

Topic 2 and 12 - Atomic structure
**vaporizer (where the sample is vaporized), **ionizer (where atoms are bombarded with high energy e-  e- knocked off the atoms. Only ions with a +1 charge are formed, in practice), **accelerator (where an electric field accelerates them), **deflector (where a magnetic field deflects them; the smaller the mass and the higher the charge, the greater the deflection) and **detector (which measures both the mass and relative amounts of ions present.
 * Atomic emission spectra:	The characteristic line spectrum that occurs as a result of energy being supplied to individual elements. When energy is supplied to an atom, e- are excited from their ground state to a higher energy level. The e- dropping from higher energy levels to lower emit energy, which can be observed in a spectrum. As e- can only exist in fixed energy levels, the energy in the emissions are characteristic for each type of atom. Lines converge toward high energy end of spectrum as the energy levels themselves are convergent.
 * Atomic number:	Number of protons in the nucleus.
 * Aufbau principle:	The principle that states that lowest energy levels are filled first. The starting order is 1s2s2p3s3p4s3d…
 * Hund’s rule:	Orbitals within the same sub-shell are filled singly first and have parallel spins
 * Ionization energy, first:	The energy required to remove one mole of electrons from one mole of gaseous atoms in the ground state to produce one mole of gaseous ions. Increases across a period (due to increasing nuclear attraction), except for slight drops (due to the commencement of pairing of e- into orbitals  greater electron repulsion). Decreases down a group (due to increased number of energy levels  increased electron shielding).
 * Isotope:	The same elements have different number of neutrons, similar chemical properties but different physical properties
 * Line spectrum:	A part of the continuous spectrum of visible light that can be seen during the emission or absorption of certain wavelengths by electron transitions.
 * Mass number:	Total number of nucleons.
 * Mass spectrometer:	A device for determining relative atomic masses and their relative abundances. Composed of:
 * Orbital:	A region of space around the nucleus of an atom that is occupied by a maximum of two e- at any given time. The types of orbitals are s (spherical), p (dumbbell-shaped), d and f.
 * Pauli’s exclusion principle:	two electrons occupying a single orbital must have opposite spins.
 * Relative abundances:	The percentage of natural occurrence of an isotope of an element.
 * Relative atomic mass:	The weighted mean of all the naturally occurring isotopes of the element relative to 12C. No units.
 * Spin:	A quantum property of electrons that can be imagined as the electron spinning on an axis.
 * Sub-level:	the set of orbitals with the same energy within a main energy level. An s sub-level contains one s orbital; a p sub-level contains 3 p orbitals; a d sub-level contains five d orbitals; f contains 7 f orbitals.
 * Valence electrons:	The e- in the highest main energy level.

Topic 3 and 13 – Periodicity

 * Alkali metals:	Group 1 elements. Strength of metallic bond gets weaker as atoms get larger.
 * Anion:	A negative (–) charged ion. Decrease in size across a period as they are isoelectronic but have an increased nuclear charge. Contain more e- than their parent atom, so they are larger in size.
 * Atomic radius:	Half the distance between the nuclei of two bonded atoms of the same element. Decreases across period as nuclear charge increases. Increases down a group because of greater number of energy levels.
 * Catalyst:	A substance that increases the rate of reaction while being recoverable in the end stage of the reaction, unchanged. Examples of catalytic transition metals: Fe is used in Haber process; V2O5 in Contact process; Ni in hydrogenation reactions; MnO2 with hydrogen peroxide.
 * Cation:	A positive (+) charged ion. Decrease in size across a period. Contain less e- than their parent atom, so they are smaller in size.
 * Chloride:	Chlorides of Na and Mg have an ionic structure, while all the remaining chlorides of period 3 elements have simple covalent structures. Still, Al2Cl6 can act as a poor conductor. NaCl dissolves in water to give a neutral solution, MgCl2 gives slightly acidic solution, while all other chlorides react vigorously with water to produce acidic solutions of HCl together with fumes of hydrogen chloride.
 * Colored complex:	A complex is a compound in which molecules or ions form dative bonds to a metal atom or ion. Colors are due to e- transitions between different d orbitals.
 * Co-ordination number:	Number of lone pairs bonded to the metal ion. Cl- often gives 4 coordinate bonds, CN- gives 6, H2O gives 6 and NH3 gives 4 or 6.
 * D-d transition:	The excitation of an e- from the lower of two energy level groups to the upper. As the ligand approaches the metal, the five d orbitals split. The difference in energy between the two levels corresponds to the wavelength of visible light, as incoming light causes energy of a particular wavelength to be absorbed by e- that are excited from the lower level to the higher. The amount that the d orbitals are split will determine the exact color.
 * Degenerate:	Of equal energy. In a free ion, the five d orbitals are degenerate.
 * Electronegativity:	Relative measure of the attraction that an atom has for a shared pair of e- when it is covalently bonded to another atom. Inversely proportional to size of atom. F, fluorine, is the most electronegative element.
 * Group:	Elements with the same number of valence e-.
 * Halide ions:	Ions of the halogens. Their presence can be detected by the addition of silver nitrate. AgCl is white, AgBr is cream-colored, and AgI is yellow. Silver halides react with light to form silver metal.
 * Isoelectronic:	Containing the same number of e-.
 * Ligand:	A species which contains a non-bonding pair of electrons, able to form coordinate/dative covalent bonds
 * Melting point:	Depends on both the structure of element and type of attractive forces holding the atoms together. Increases across the period while following elements which exhibit metallic bonding (due to increased strength following increased number of valence e-.) Highest m.p. of period lies with macromolecular covalent structure (with very strong bonds). Sharp decrease in m.p. with elements that exhibit simple molecular structures with only van der Waals’ forces between them. Lowest m.p. with noble gases, which are monatomic. Down Group 1, m.p. decreases as atoms get larger and strength of metallic bond get weaker. Down Group 7, van der Waals’ forces increase as molar mass increases  m.p. increases.
 * Metalloid:	An element that possesses some of the properties of a metal and some of a non-metal. While metal oxides tend to be basic and non-metal oxides tend to be acidic, metalloid oxides such as aluminium oxide can be amphoteric.
 * Oxide:	Metal oxides are ionic (explains conductivity, m.p. and b.p.) and react with water to form alkaline solutions. SiO2 is covalent macromolecular, and the remaining oxides are simple covalent. Oxides of period 3 elements are solid from Na2O to P4O10 and P4O6, while SO3 and Cl2O7 are liquid and SO2 and Cl2O are gases at 25C. Al2O3 and SiO2 do not react with water, but Al2O3 can act amphoterically depending on whether it is reacted with a base or an acid. Remaining oxides are acidic.
 * Period:	Elements with the same outer shell of valence e-.
 * Periodicity:	The repeating pattern of physical and chemical properties as shown by the different periods.
 * Structure, giant covalent:	Very hard but brittle. Very high m.p. and b.p. Do not conduct in any state. Insoluble.
 * Structure, giant ionic:	Hard but brittle. High m.p. and b.p. Conduct when molten or aqueous, but not as solids.
 * Structure, giant metallic:	Malleable, not brittle. M.p. and b.p. dependent on no. of valence e-. Good conductivity.
 * Structure, molecular covalent:	Usually soft and malleable unless hydrogen bonded. Low m.p. and b.p. Do not conduct in any state. Often soluble in non-aqueous solvents, unless they can hydrogen bond to water.
 * Transition element:	An element that possesses an incomplete d sub-level in one or more of its oxidation states. Often very efficient catalysts as they can exist in a variety of oxidation states (all except Ti have oxidation state of +2). Form colored complexes.

Topic 4 and 14 – Bonding

 * Allotrope: Occur when an element can exist in different crystalline forms, such as in carbon, which can exist as graphite, buckminsterfullerene (bucky ball) and diamond. Diamond is exceptionally hard because there is no plane of weakness in the molecule made up of sp3 hybridized carbon atoms. In graphite, the carbon atoms are sp2 hybridized. Remaining e- after the three σ bonds, are delocalized, resulting in the fact that graphite is an excellent lubricant and a good conductor of electricity.

 * Bond length and strength: Depends on strength of attraction that two nuclei have for the shared e-. Generally, the stronger the bond, the shorter its length.

 * Bond polarity:	A polarity caused by a difference in electronegativity between the elements. The greater the difference, the greater the polarity.

 * Bond, π: Pi bond. A radial bond formed by the sideways overlap of p orbitals with e- densities concentrated above and below a line drawn through the two nuclei. Double bonds have one π bond, while triple bonds have two which are perpendicular to each other.

 * Bond, σ: Sigma bond. An axial bond formed by the head on/head-to-head overlap of atomic orbitals from two different atoms along the line drawn through the two nuclei, with e- densities concentrated along the line. Single, double and triple bonds have one σ bond.

 * Covalent bond: Bonding by the sharing of e-. The e- are shared and attracted by both nuclei resulting in a directional bond between the two atoms.

 * Dative bond: A bond in which both e- come from one of the atoms. Also known as coordinate bond.

 * Ionic bond: A bond by which e- are transferred from one atom to another to form ions with complete outer shells. In an ionic compound the + and – ions are attracted to each other by the electrostatic force between them, and build up into a strong lattice. Have relatively high m.p. Ionic bonds occur between elements with a great difference (>1.8) in electronegativity.

 * Conductivity: The extent to which a substance can conduct electricity. Must possess e- or ions that are free to move.

 * Delocalization: The sharing of a single e- pair by more than two atoms.

 * Forces, dipole-dipole: Permanent electrostatic forces of attraction between polar molecules. Stronger than van der Waals’.

 * Forces, Hydrogen bonding: Occurs when hydrogen is bonded directly to a highly electronegative element (N, F, or O). Stronger than dipole:dipole forces.

 * Forces, van der Waal’s: Temporary dipole forces due to momentary unevenness in spread of e-. Weakest of intermolecular forces. Increase with increasing molar mass.

 * Formal charge theory:
 * If compound is covalent, treat the entire molecule; if ionic, treat each ion separately.
 * Determine total no. of valence e- available.
 * Organize atoms such that there is a central atom (usually the most electronegative) surrounded by ligands.
 * i) One pair of e- between central atom and each ligand atom.
 * ii)three more pairs on each ligand (except hydrogen).
 * iii)remaining e- pairs around central atom.
 * Calculate formal charge on central atom. Should be equal to charge on species, otherwise form a multiple bond with ligand atom that has most – formal charge. Repeat 5.

 * Formal charge:	A hypothetical measure of the number of e- originating from an atom. F = V – (n + b/2), where V is valence e-, n is e- in lone pairs and b is e- shared as bonds.

 * Hybridization:	The combination of orbitals to create new orbitals that are more energetically feasible for bonding. Bonds that are sp3 hybridized have a regular bond angle of cos-1(-1/3) ≈ 109.5°, sp2 have cos-1(-1/2) = 120°, and sp have cos-1(-1) = 180°.

 * Lewis structure:	Diagram showing arrangement of e- in a molecule. Usually only shows valence shells.

 * Metallic bonding:	The valence e- in metals become detached from the individual atoms so that the metals consist of a closely packed lattice of + ions in a ‘sea’ of delocalized e-. Forces of attraction are between ions and e- and not between the ions themselves, which means that metals are malleable and ductile.

 * Molecular polarity:	Depends on both the bond polarity and the symmetry.

 * Resonance hybrid:	Structures that arise from the possibility to draw a multiple bond in different positions equivalently. Can be better explained by delocalization.

 * Solubility:	The extent to which one substance dissolves in another. ‘Like tends to dissolve like.’

 * VSEPR theory:	Valence Shell Electron Pair Repulsion theory. States that pairs of e- arrange themselves around the central atom so that they are as far apart from each other as possible. Greater repulsion between lone pair of e- than bonded pairs.

Topic 5 – States of Matter

 * Gas:	Widely spaced particles that completely fill the container.
 * Ideal gas:	A gas for which the relationship pV = nRT holds true.
 * Liquid:	Has fixed volume and takes up shape of container.
 * Maxwell-Boltzmann distribution:	Graph showing the distribution of kinetic energies among molecules.
 * Molar volume:	At 273 K and 1 atm, one mole of any gas will occupy 22.4 dm3.
 * Solid:	Has fixed shape and fixed volume. Particles held together by intermolecular forces in a fixed position.

Topic 5 and 15 – Energetics

 * Bond enthalpy:	The average enthalpy change of breaking a bond between gaseous atoms into its constituent gaseous atoms.
 * Born-Haber cycle:	Energy cycles for the formation of ionic compounds. If there is little agreement between the theoretical and experimental values, this could indicate a degree of covalent character.	ΔHf = ΔHat(1) + ΔHat(2) + ΔHIE(1) + ΔHEa(2) – ΔHLatt
 * Calorimetry:	A device for measuring enthalpy changes for reactions. In a simple calorimeter all the heat evolved in an exothermic reaction is used to raise the temperature of a known mass of water.
 * Electron affinity:	Enthalpy change when an e- is added to an isolated atom in the gaseous state.
 * Endothermic:	A reaction in which energy is absorbed. ΔH is +. Reactants more stable than products.
 * Enthalpy:	The internal energy stored in the reactants. Only changes in enthalpy can be measured.
 * Entropy:	A measure of the disorder of a system. The absolute entropy can be found in terms of the probability of a state existing. Things causing entropy to increase: 1) increase of number of moles of gaseous molecules; 2) change of state from solid to liquid or liquid to gas
 * Exothermic:	A reaction in which energy is evolved. ΔH is –. Products more stable than reactants.
 * Gibb’s free energy:	Must be – for reaction to be spontaneous. 	ΔG = ΔH – TΔS
 * Heat:	A measure of the total energy in a given amount of substance.
 * Hess’s law:	Enthalpy change for a reaction depends only on difference between enthalpy of products and enthalpy of reactants  independent of pathway.
 * Lattice enthalpy:	The endothermic process of converting one mole of a crystalline solid into its gaseous ions, or the reverse exothermic process. The lattice enthalpy increases with decreasing size of the ions and increasing charge.
 * Spontaneous:	A reaction that has a natural tendency to occur.
 * Standard conditions:	298 K and 1 atm.
 * Temperature:	A measure of the average kinetic energy.

Energy Definitions
It should be noted that many of the energy definitions can be considered in the reverse direction with a corresponding change of sign for the energy. Bond formation = exothermic ΔH negative, bond cleavage = endothermic ΔH positive

 * Standard enthalpy of vaporisation: The energy required to vaporise one mole of a liquid.
 * Enthalpy of atomisation: The energy required to produce one mole of gaseous atoms from an element in its standard state.
 * Bond dissociation enthalpy: The energy change when one mole of a specific bond is broken or created under standard conditions.
 * Standard bond enthalpy: The average energy change when one mole of covalent bonds is broken or created under standard conditions.
 * Enthalpy of Combustion: The energy released when one mole of a compound is burned in excess oxygen completely.
 * Standard enthalpy of formation: The energy change when one mole of a compound is formed from its constituent elements in their standard states under standard conditions.
 * Standard enthalpy of solution: The energy change when one mole of a substance is dissolved in an infinite amount of water under standard conditions.
 * Standard dehydration enthalpy: The energy change when a particle is taken from infinite separation in the gaseous state to its position in an aqueous lattice.
 * Ionisation energy: The energy required to remove one mole of electrons from one mole of gaseous atoms in the ground state to produce one mole of gaseous ions.
 * Lattice enthalpy: The energy change when one mole of an ionic substance is broken into its constituent ions at infinite separation.
 * Enthalpy of Hydration: the energy change when 1 mole of gaseous ions are dissolved in water to create a solution of infinite dilution
 * Enthalpy of Solution: the energy change when 1 mole of a solid crystalline/ionic substance dissolves in water to give a solution of infinite dilution

Topic 7 and 17 – Equilibrium
Le Chatelier’s principle:	If an equilibrium is subjected to a stress, the equilibrium will shift to minimize the effect of the stress.
 * Closed system:	A system in which neither matter nor energy can be lost or gained. An equilibrium can never occur in a system that is not closed.
 * Contact process:	The synthesis of sulphuric acid, where V2O5 is used as a catalyst.
 * Equilibrium constant:	For a reaction aA + bB  cC + dD, where the small letters are coefficients and capital letters are the reactants, the equilibrium constant is [C]c[D]d/[A]a[B]b. Variable units.
 * Equilibrium, dynamic:	An equilibrium in which the rates of the forward and reverse reactions are the same.
 * Haber process:	The synthesis of ammonia, where Fe is used as a catalyst.
 * Optimum temperature:	For exothermic reactions such as the Haber process, the optimum temperature is the best compromise between yield and rate.
 * Homogeneous reaction:	A reaction in which all the species involved are in the same phase.
 * Phase equilibrium:	When the rate of vaporization is equal to the rate of condensation.
 * Vapor pressure:	The partial pressure of a vapor. Boiling occurs when a liquid’s vapor pressure equals the external pressure. The stronger the intermolecular forces the lower the vapor pressure at a particular temperature.

Topic 8 and 18 – Acids and Bases
**Indicators; **Bases, in neutralization reactions (form a salt and water with hydroxides and metal oxides; form a salt with ammonia); **Reactive metals (those above copper in reactivity series) (form salt and hydrogen); **carbonates and hydrogencarbonates (form a salt, CO2 and water). **strong base + excess weak acid; **strong acid + excess weak base; **weak acid + same acid’s salt; **weak base + same base’s salt. 1) its derivations (salts derived from a strong acid and weak base will be acidic in solution, considering that the ions of the weak base will combine, leaving an excess of H+. The strong acid will not combine as it is completely dissociated, as per definition. Vice versa with strong acid and weak base); 			2) charge density of cation (high charge density results in strong attraction to the lone pair of one of six water molecules surrounding the ion, a process by which the water molecule loses a hydrogen ion, i.e. leaving the solution acidic).
 * Acid properties:	React with:
 * Amphoteric:	Can have the properties of both a base and an acid, depending on whether it is reacting with a base or an acid.
 * Brønsted-Lowry:	An acid is defined as a proton donator, while a base is a proton acceptor.
 * Buffer:	A solution that resists changes in pH when small amounts of acid or alkali are added to it. When a small amount of acid is added, the excess of H+ ions causes the equilibrium to shift to the left  balances the difference. When a small amount of alkali is added, the OH- ions react with the H+ ions to form water. The decrease in [H+] is compensated for by an equilibrium shift to the right. Vice versa for alkali buffers. Buffer solutions are made by several means:
 * Charge density:	Charge over size.
 * Concentrated:	High number of moles of solute per dm3 of solution.
 * Conductivity:	The more a solution is dissociated into its ions, the greater its conductivity.
 * Conjugate:	The species remaining after an acid has lost a proton (conjugate base) or a base has gained one (conjugate acid). 	pKa + pKb = pKw
 * Diprotic:	Where one mole of sulphuric acid produces two moles of hydrogen ions, e.g. H2SO4.
 * End point:	The point at which the indicator changes color most rapidly.
 * Equimolar:	Containing equal concentrations.
 * Equivalence point:	Where the acid and base are in equimolar quantities. Exactly enough to react with each other.
 * Indicator:	A weak acid or base in which the dissociated form is a different color to the undissociated form. The end point occurs when the pH is approximately equal to the pKin value, assuming that the color changes when [In-]  [HIn]. Ideally, the end point corresponds to the equivalence point in a titration.
 * Lewis theory:	An acid is defined as an e- acceptor (e.g. BF3) and a base is an e- donator (e.g. NH3) by dative bond.
 * Monoprotic:	Where one mole of the acid produces one mole of hydrogen ions, e.g. HCl.
 * pH:	Power of hydrogen. 	– log [H+]
 * Salt hydrolysis:	The process by which a salt is broken down by water. The acidity of the salt depends on:
 * Strong:	An acid or a base that dissociates completely into its ions. Ka >> 1. Some strong acids: hydrochloric, sulphuric, nitric (weaker than other two). Strong bases: hydroxides of alkali metals.
 * Titration:	Technique for quantitative measure of concentration of a solution. Consider when 90% of the required base has been added to a 1M strong acid that is to be neutralized. Only 10% of the acid remains, meaning 0.01M, giving a pH of 2. When 99% has been added, the pH is 3, etc.
 * Water, ionic product of:	The equilibrium constant for the dissociation of water into its ions, where [H2O] is taken to be constant. Value of Kw increases as temperature is increased, as the dissociation is an endothermic process.	pKw
 * Weak:	An acid or base that only slightly dissociates into its ions. Ka << 1. Some weak acids: ethanoic, carbonic. *Weak bases: ammonia, aminoethane.

Topic 9 and 19 – Oxidation and Reduction
Cathode:	Where reduction takes place. In electrolysis, it is the – electrode and cations are attracted here. a) elements: 0; 			b) ion: its charge; c) oxygen: -2 (except in peroxides, -1); 			d) hydrogen: +1 (except metal hydrides, -1); e) fluorine: -1.
 * Anode:	Where oxidation takes place. In electrolysis, it is the + electrode and anions are attracted here.
 * Electrolysis:	Passage of electric current through an electrolyte. Amount of discharge is affected by: 1) current; 2) charge on ion,    3) duration of electrolysis.
 * Electrolyte:	A substance which does not conduct electricity when solid, but does when molten or in aqueous solution and is chemically decomposed in the process.
 * Electrolytic cell:	Used to make non-spontaneous redox reactions occur by providing energy in the form of electricity from an eternal source.
 * Electroplating:	A process of coating one metal with a thin layer of another metal, by electrolysis.
 * Half cell:	A metal in contact with an aqueous solution of its own ions.
 * Oxidation number:	Ox. no. of:
 * Oxidation:	The loss of e-, the gain of oxygen, the loss of hydrogen or the increase in oxidation number.
 * Oxidizing agent:	A substance that readily oxidizes other substances. Oxidizing agents are thus reduced. The higher the oxidation number, the better an oxidizing agent it is, generally.
 * Reactivity:	A measure of the readiness of a substance to gain or lose e.. The stronger the reducing agent or oxidizing agent, the more reactive it is.
 * Redox reaction:	A reaction in which there is a transfer of e-, i.e. reduction and oxidation occurring simultaneously.
 * Reducing agent:	A substance that readily reduces other substances. Reducing agents are thus oxidized.
 * Reduction:	The gain of e-, the loss of oxygen, the gain of hydrogen or the decrease in oxidation number.
 * Salt bridge:	Allows the free movement of ions in a voltaic cell. Paper dipped in a saturated solution of KNO3 is an example of a salt bridge.
 * Shorthand notation:	For a voltaic cell. Example: Cu(s)/Cu2+(aq) || H+(aq) / H2(g)
 * Standard conditions:	298 K, 1 atm, 1.0 M.
 * Standard electrode potential:	Measuring a potential cannot be done as this interferes with the system being investigated. However, the electrode potential of one half cell can be compared against another half-cell, by convention, the hydrogen half-cell, which is arbitrarily given a value of 0 V.
 * Standard electromotive force:	Difference between the two standard electrode potentials of the two half cells.	Ecell
 * Standard hydrogen electrode:	Arbitrarily assigned a potential of zero. Electrode consists of an inert metal such as platinum dipped into a 1 M solution of HCl, where hydrogen gas at 1 atm flows in. Platinum black, a very finely divided platinum, catalyzes the electrode equilibrium.
 * Voltaic cell:	Two different half-cells connected together to enable to e- transferred during the redox reaction to produce energy in the form of electricity. The e- are produced at the half-cell that is most easily oxidized.

Topic 10 and 20 – Organic Chemistry
Isomers, functional group:	Where the isomers contain different functional groups. **nature of halogen atom (the less reactive the atom  the weaker the bond with the C  it reacts more readily); **nature of halogenoalkane (tertiary > secondary > primary). Octane number:	Measure of the combustion efficiency of petrol engine fuel Heptane is assigned an arbitrary value of 0, while isooctane is assigned an octane number of 100. Peptide:	Molecule formed by aa’s joined together by peptide bonds (by condensation reaction in which water is lost).
 * Acidity:	Carboxylic acids are weak acids as the – charge on acid anion can be delocalized over three atoms and does not readily attract H+ ions. Amines are weak bases. Can be considered as substituted compounds of NH3.
 * Alcohol, primary:	With two hydrogen atoms on the neighboring carbon atom (next to the hydroxyl group). Can be oxidized to aldehydes (by loss of hydrogens) and then to carboxylic acids (by gain of oxygen). Ethanol can be oxidized to ethanal by the orange Cr2O72- ion, which itself becomes reduced to the green Cr3+ ion.
 * Alcohol, secondary:	With one hydrogen atoms on the neighboring carbon atom. Can be oxidized to ketones (by loss of hydrogens).
 * Alcohol, tertiary:	With no hydrogen atoms attached to the neighboring carbon atom. Cannot be oxidized further.
 * Benzene:	Hexagonal shape with delocalized  bonds. Undergo substitution rather than addition reactions.
 * Boiling and melting point:	Depend on intermolecular forces. The greater the intermol. forces, the higher the m.p. and b.p.
 * Bromination:	Yellow/orange bromine is decolorized when added to an alkene due to addition reaction. Used to test for alkenes.
 * Carbocation:	A cation in which the carbon carries most of the + charge. Can be formed during SN1 substitution.
 * Carbon:	Group 4 element which always forms 4 covalent bonds, as it has 4 e- in its valence shell.
 * Chiral center:	An asymmetric carbon atom, i.e. has four different functional groups attached to it.
 * Cis-isomer:	The geometric isomer in which the similar groups are on the same side of the double bond. Commonly polar.
 * Condensation reaction:	Reaction in which two molecules join together with the loss of a small molecule, typically water.
 * Dehydration:	Loss of water. Alcohols can be dehydrated when they are refluxed with condensed sulphuric acid. As sulphuric acid is an oxidizing agent  able to react with the product, phosphoric acid is frequently used instead.
 * Enantiomer: 	See ISOMERS, OPTICAL.
 * Environment, hydrogen:	The immediate neighborhood (neighboring and next carbon) of a hydrogen atom.
 * Esterification:	Process by which an alcohol and a carboxylic acid are converted into an ester and water, often with acid catalysis.
 * Fission, heterolytic:	Bond breaking in which the more electronegative of the two atoms joined by the bond takes both of the e-.
 * Fission, homolytic:	Bond breaking in which each atom takes one of the e- in the bond, creating free radicals.
 * Fragmentation pattern:	Excess energy from impact of e- forming ion in mass spectrometer will often cause molecule to fragment. The mass of the fragments can indicate details about structure of original molecule.
 * Free radical:	A species containing at least one unpaired e-, as a result of homolytic fission. Very reactive.
 * Func. gr., alcohol:	-OH. IUPAC: -anol.
 * Func. gr., aldehyde:	-CHO. IUPAC: -anal.
 * Func. gr., alkane: 	No functional group. IUPAC: -ane.
 * Func. gr., alkene:	C=C. IUPAC: -ene.
 * Func. gr., amide:	-CONH2. IUPAC: -anamide.
 * Func. gr., amine:	-NH2. IUPAC: amino- or –ylamine.
 * Func. gr., carboxylic acid:	-COOH. IUPAC: -anoic acid.
 * Func. gr., ester:	-COO-. IUPAC: alkyl acid-oate, e.g. methyl propanoate. Derived from carboxylic acid and alcohol. Often used as flavoring as they have characteristic smell.
 * Func. gr., ether:	-O-.
 * Func. gr., halogenoalkane:	-X (i.e. –Cl, -Br, -I). IUPAC: halogeno-.
 * Func. gr., ketone:	-CO-. IUPAC: -anone.
 * Halogenoalkane, primary:	Halogenoalkanes that have one alkyl group attached to the carbon atom bonded to the halogen. Undergo SN2 mechanism in nucleophilic substitution.
 * Halogenoalkane, tertiary:	Halogenoalkanes that have three alkyl groups attached to the carbon atom bonded to the halogen. Undergo SN1 mechanism in nucleophilic substitution.
 * Homologous series:	A group of compounds that can be described by a general formula. Have similar chemical properties, but gradually changing physical properties. When all other factors remain constant, increased molar mass means increased intermolecular forces. Often, long carbon chains can negate the effect of a polar end  molecule is non-polar.
 * Hydration:	Addition of water. Ethanol can be formed from addition of water to ethene.
 * Hydrocarbon:	Compounds containing only carbon and hydrogen.
 * Hydrogenation:	Addition of hydrogen. Can be used to reduce number of double bonds in polyunsaturated vegetable oils present in margarine, causing it to become a solid at room temperature.
 * Hydrolysis:	Process by which a molecule is broken down by water.
 * Isomer:	Different compounds that have the same molecular formula.
 * Isomers, hydrocarbon chain:	Where there is a difference in the structure of the hydrocarbon chain.
 * Isomers, optical:	Where a molecule shows optical activity in its mirror images. Occurs when there is one or more chiral centers.
 * Isomers, positional:	Where the position of the functional group is different.
 * Isomers, stereo-:	Where the molecules have a different spatial arrangement of atoms and hence different 3D shapes. Subdivided into geometric and optical isomers (enantiomers).
 * Isomers, structural:	Where the atoms have a different structural formula altogether. Subdivided into positional, hydrocarbon chain and functional group isomers.
 * Knocking:	Pre-ignition, a result of a great number of free radicals. The greater the octane rating, the less likely it is that knocking occurs. Knocking can also be reduced by antiknock agents, such as lead. Unfortunately, lead is poisonous when released into atmosphere.
 * Mechanism, SN1:	A unimolecular process by which a halogenoalkane undergoes nucleophilic substitution. A two-step mechanism: a rate-determining step in which the bond between the carbocation and the halogen are broken, followed by a step in which the nucleophile is attracted to the carbocation. Faster than SN2, as the formation of the intermediate carbocation is faster than the SN2 route which involves a transition state with relatively high activation energy.
 * Mechanism, SN2:	A bimolecular process by which a halogenoalkane undergoes nucleophilic substitution. Mechanism involves formation of a transition state which involves both of the reactants.
 * Monomer:	Components of a polymer.
 * Nucleophile:	According to Siw, “nuclear loving.” The species that donates the e- pair in an organic chemical reaction. A nucleophile is also a Lewis base. Typical nucleophiles are CN-, OH- and NH3.
 * Nucleophilic substitution:	Substitution that occurs with a halogenoalkane reacting with a nucleophile. Rate depends on:
 * Optically active:	Can rotate the plane of polarization in opposite directions. Enantiomers are optically active.
 * Organic chemistry:	The chemistry of carbon compounds.
 * Peptide bond:	-C=ONH-. Bond formed as the result of condensation reaction between carboxyl group from one aa and the amino group from the other.
 * Peptide, di-: 	Two aa’s joined together.
 * Peptide, oligo-: 	Several aa’s joined together.
 * Peptide, poly-: 	More than 20 aa’s joined together.
 * Peptide, tri-: 	Three aa’s joined together.
 * Polarimeter:	An instrument for measuring the degree of rotation of the plane of polarization.
 * Polymer:	Gigantic molecule made up of monomers.
 * Polymerization, addition:	Forming a polymer by addition of monomers.
 * Polymerization, condensation:	Forming a polymer by substitution reaction between monomers, each having two functional groups.
 * Potassium dichromate:	K2Cr2O7. A strong oxidizing agent.
 * Reaction, addition:	A reaction in which the reactant is added across a C=C bond, converting it to a C-C bond. Addition reactions with water requires an H2SO4 catalyst. Addition reactions with hydrogen use Ni as catalyst.
 * Reaction, substitution:	A reaction in which one group is substituted for another. Substitution reactions with halogenoalkanes are nucleophilic substitutions. Benzene does not undergo substitution reactions readily as its  bonds are delocalized.
 * Reflux:	A condenser which causes any vapor produced to condense and returns to the flask and continues to react. If the carboxylic acid is desired from the oxidation of a primary alcohol, this must be done under reflux. On the other hand, if the aldehyde is desired, this can be distilled from the reaction mixture as soon as it is formed.
 * Saturated:	Containing only single bonds. Alkanes are saturated.
 * Spectrometry, mass:	Separating ions according to mass.
 * Spectroscopy, IR:	Analyzing the bonds present within a molecule by sending infrared light through it, causing the bonds to absorb radiation of characteristic frequencies.
 * Spectroscopy, NMR:	Analysis of hydrogen environments to deduce the structure of a molecule. Measured in ppm relative to TMS.
 * Trans-isomer:	The geometric isomer in which the similar groups are on different sides of the double bond. Commonly non-polar.
 * Unsaturated:	Containing double bonds. Alkenes are unsaturated. Can be tested for by bromination.

title: IB Chemistry/Definitions


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Basic Computing Using Windows/Computers and Peripherals

The first thing you should know is that a computer is an automatic, electronic, data-processing machine that takes in facts and figures known as data, and then processes or organizes it in some useful way (what's commonly called computation). Afterwards it outputs, or displays, the results for you to see as information. Keep in mind that data is not information; rather, information is the knowledge that you, the end-user, derive from accurate data that's entered into a computer. Only after processing, is data transformed into information which is then used for decision making. Each part of a computer can be classified as either hardware or software.

Types of computers
There are actually a lot of different kinds of computers. Most of what we'll go through here are classified as Personal Computers (PCs). Most people will describe a computer as a box with a monitor attached; this is a desktop, which are computers designed to stay in one place. There are also much more powerful computers called servers that can be as big as a room or even a house. This is what companies use to, say, power websites and do computations that one person wouldn't really need for themselves. The Wikimedia Foundation even has them!

Some computers are designed to have all its components in one place in a small package, making it easy to travel with it and use it as you go. Smaller, portable desktops are called laptops or notebooks, and even smaller laptops are called netbooks that can be carried in just one hand. In the 2000s, Tablet PCs were common, and unlike laptops, they were just a screen that could be written to with a stylus instead of a mouse. Everything else in the computer was in the screen itself, or behind it. Personal Digital Assistants (PDAs) were also common, but have been replaced by smartphones and tablets, which are indeed computers! Smartphones have touchscreens that can be tapped using your fingers to do different things for you, like be a calculator or type text. Any computer that doesn't need to be plugged into a wall outlet to work have batteries instead that generally last for about three to eight hours, with some reaching twelve and beyond before needing to be recharged. Smaller devices tend to last longer.

Hardware
Hardware refers to all of the physical components of a computer. These parts may include:
 * A soft output device (most commonly known as a monitor, but televisions can also be used)
 * A hard output device (i.e. a printer)
 * A keyboard
 * A pointing device (usually a mouse, but varieties exist)
 * Any buttons on the case/chassis of the computer, such as a power button
 * Internal components in the case such as a processor, memory, storage, motherboard, and power supply
 * Any cables that connect these components together

The monitor
You might think among many people today that the part of the computer that normally displays pictures and text is the computer itself. This is usually not true. With a standard desktop computer, the part that does the actual computing is often in a separate box. With a laptop or a netbook, the computing is done in the hardware under the keyboard. The rest is done under the monitor. Computers may also refer to the whole assembly of the hardware. When the inside of a computer is actually inside the monitor itself, the computer is called an all-in-one.

Just like computers, there are different types of monitors. Throughout the early era of computing, both monitors and televisions alike used cathode ray tubes, and were often referred by their shortform, CRTs, which could have very high refresh rates for games. However, in the 2000s, the industry made a switch to liquid-crystal displays (LCDs), which had flat panels and were lighter. Now, light-emitting diodes (LEDs) are used near universally for computer monitors.

Monitors are commonly known as soft output devices, because the information that's displayed doesn't stay on the monitor.

The printer
Printers put data on paper. This is why it's referred to as a hard output device. Different types of printers include Xerox, laser, and deskjet, and scanners may also be included, where they can dial out to a number and send pictures of paper. They may also be sent to the computer for viewing at any time. These are fax machines.

Input devices
There are also different kinds of input hardware. For most personal computers, the two important ones are the mouse and the keyboard. The mouse is used to move the cursor (or arrow) around the screen. A keyboard is used to enter (type) letters, numbers, and other symbols into a computer. With the advent of smartphones, fingers have become the mouse, and a keyboard interface appears when text needs to be entered in.

Software
Software is all of the instructions and programming that a computer uses to do what you ask it to do. Packages of software are often called programs, and an operating system is a collection of programs that help all the other programs run. Think of software as the power behind the hardware. Without software, your computer doesn't do anything. Without hardware, the software can't even exist. Computers do not think for themselves, so they need software, which is made to manipulate the computer's hardware in such a way that you, the user, can understand.

As an example, a calculator is a very simple form of computer. It is nowhere near the complexity or versatility of a personal computer. You input information as series of key presses, and the calculator computes the result which is displayed as output on a small screen. Calculators are faster than humans, so this creates utility in the form of time saved. Calculators can also repeat calculations easier than humans.

Computers store all data in binary, which is a number system that only uses ones (1) and zeros (0). One digit in binary code is called a bit, and eight bits is called a byte. A byte is the amount of space one letter takes up. One thing to bear in mind is that all the extra detail about how the letter looks must also be stored in binary code and so word processor documents use more space than one byte per letter.

Firmware
Some software is not designed to be changed so that when the hardware turns on, it runs the same thing every time. Firmware is common for a computer's BIOS, as well as arcade machines since they're meant to use only one game.

Turning the computer on
Desktops often have a power button at the front of the case. When turning a desktop on, first make sure that the power supply is connected to the back of the computer and a power outlet, and then press the button. On laptops and tablets, simply locate the power button and press it.

Windows may present a login screen, in which a username and/or password will be prompted. Newer versions of Windows may not require the username to be typed. On Windows 10, a PIN may be prompted in the place of a password. Type the password into the box, then press the enter key, or click on (put the cursor on top of and push the left button on the mouse) the OK button if there is one. If on Windows 8 and newer the password/PIN box does not come up, it just means the computer is not set to have a password. We will learn more about this later. If this box did not come up, but instead a screen with pictures and names of the user accounts, click the picture with the correct username beside it, type in the password if there is one, and press enter on your physical or virtual keyboard.

Turning off the computer To turn the computer off:

These methods will ensure that your computer will shut down correctly. However, one other method is to hold the power button for approximately ten seconds, or flip the power supply's switch on the back of the computer. This is known has a hard shutdown, and should only be done if the computer freezes for as much as thirty seconds. Upon doing a hard shutdown, Windows may tell you that the computer was not shut down correctly.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


text:
IB Chemistry/Option Definitions

Option B – Human Biochemistry - SL
Amino acid: A compound in which an amino group and a carboxylic acid group are present. There are 20 aa that occur naturally. Can be polymerized to form proteins. Exists as a zwitterion at their isoelectric point. All except glycine can show optical activity. aa

Amino acids, essential: Aa’s that our body is not able to produce and we need to have them as nutrients. There are 10 of these.

Amino-acids, non-essential: Aa’s that we are able to produce in our body.

Anabolic steroids: All steroids contain characteristic four-ring structure. Have similar structure to testosterone. Build up muscle.

Anabolic: Processes in which complex molecules are made from simpler ones, such as in photosynthesis.

Calorie: The energy required to raise the temperature of 1g of water by 1oC.

Calorific value: The energy content of food.

Carbohydrates: Produced by photosynthesis in plants. Used to 			1) provide energy; 			2) store energy (starch is stored in liver in form of glycogen); 3) precursors for important biological molecules (e.g. they are components of nucleic acids).

Catabolic: Processes in which molecules are broken down into simpler ones, such as aerobic respiration.

Denaturation: When the three-dimensional conformation of the structure is destroyed, and the protein becomes biologically inactive. Denaturing agents are:

'''			1) heat; 			2) UV-radiation; 3) strong acids and bases; 			4) concentrated salt solutions; 5) heavy metals (no, not that kind… examples are Pb, Hg, etc).

Diet: Well-balanced diet consists of about 60% carbohydrate, 20-30% protein and 10-20% fat. Should include essential vitamins and fifteen essential minerals. Amount of food required depends on age, weight, gender, and daily activity.

Eluent: The solvent in which the chromatographic paper is placed in paper chromatography.

Fats: Solid triglycerides at room temperature. Contain only saturated carboxylic acid groups. Uses of fats: 1) efficient way to store energy (in adipose tissue); 			2) thermal insulation; 3) protection; 			4) form part of cell membranes, 5) source of energy (can be oxidized more than carbohydrates).

Fatty acid: Long chain carboxylic acids.

Feedback mechanism: When a product of a process or a hormone reaches a certain level, it inhibits (negative feedback) or promotes (+ feedback) a further response.

Food calorimetry: Measuring the energy content of food.

Furanose: Five membered ring containing an oxygen atom, such as in fructose.

Glucose: A hexose monosaccharide. Form of glucose found in nature is D-glucose, which can exist in two separate crystalline forms: 1) -D-glucose (OH groups are down, down, up, down; following carbon chain); 			2) -D-glucose (up, down, up down). C6H12O6

Glycosidic link: Link between two sugar in a polysaccharide, formed by condensation reaction.

GM food: Genetically modified food. Benefits: Improve flavor, nutritional value, and shelf life. Could incorporate anti-cancer substances. Could make plant more resistant to disease. Concerns: unpredictable outcome. May cause antibiotic-resistance. May alter balance of ecosystems.

Hard water: Contains Mg2+ or Ca2+. Prevents soap from working efficiently as it reacts with the anion of the soap, producing a precipitated salt.

Hormone, adrenalin: Responsible for ‘fight or flight’ response (goose bumps, increased pulse/BP). Produced in adrenal medulla.

Hormone, insulin: Made up of 51 aa residues. Decreases glucose levels in blood by making liver absorb glucose in the form of glycogen. Insulin produced in -cells of Islets of Langerhans.

Hormone, thyroxine: Regulates metabolism. Produced in thyroid gland. Hypothalamus releases local hormone which tells anterior pituitary to release thyroid SH (+ feedback). TSH tells thyroid glands to release thyroxine (+ feedback). When the concentration of thyroxin reaches a certain level, a – feedback is sent to hypothalamus, ceasing production of the local hormone.

Hormones, sex: Responsible for development of secondary sexual characteristics. Both estrogen and testosterone produced in testes (males) and ovaries (females). They are all steroids  contain characteristic four-ring structure.

Hormones: Chemicals produced in glands and transported to specific target cell by blood stream, and binds to a receptor site on or within the target cell  produces a specific physiological response. Glands are controlled by pituitary gland, which in turn is controlled by the hypothalamus. Hormones act as chemical messengers. Hydrophilic:''' Describing part of molecule that is attracted to water.

Hydrophobic: Describing part of molecule that repels water.

Iodine number: Number of grams that reacts completely with 100g of a triglyceride. The higher the iodine number, the more unsaturated the triglyceride.

Isoelectric point: The pH value at which the average charge on the molecules of a compound is zero.

Lactose: Disaccharide in which -D-galactose and -D-glucose are joined by glycosidic link.

Lipids: Biological substances that are soluble in non-polar solvents (generally). Lipases in digestive system degrade lipids.

Menstrual cycle: Pituitary gland releases follicle SH, which travels to ovaries causing release of estradiol. Two weeks later, – feedback stops release of FSH and triggers release of luteinizing hormone, which travels to ovaries and releases progesterone. Progesterone causes egg to be transported to uterus. If egg is fertilized, it embeds itself on uterine wall and hormone levels rise dramatically, otherwise hormone levels fall and menstruation occurs.

Metabolism: The network of biochemical reactions that supports life.

Micelle: The particle formed when the hydrophilic tail dissolves in oil or grease.

Ninhydrin: An organic dye. Causes coloration of aa’s. Used to see how far aa’s have moved in both paper chromatography and electrophoresis.

Nutrient: Substances that are required by an organism as food.

Oils: Liquid triglycerides at room temperature. Contain at least one double bond, i.e. they are unsaturated. The more unsaturated, the lower the m.p. due to its inability to pack so closely together  the surface area decreases  decrease in the van der Waals’ forces between the molecules. Number of C=C bonds can be determined by addition reactions with I2. See IODINE NUMBER.

Oral contraceptives: Most common ‘pill’ contains a mixture of estradiol and progesterone  mimics the high hormonal levels of pregnancy, in turn preventing the release of more eggs.

PAGE: Polyacrylamide gel electrophoresis.

Phospholipid: Form major part of plasma membranes. Phosphate group is hydrophilic while lipid part is hydrophobic.

Polyunsaturated oils: An oil containing several double bonds.

Protein structure, electrophoresis: Electrophoresis is carried out on a medium called PAGE. Sample is placed in center of gel, and a potential difference is applied across it. The movement of the aa depends on the pH of the buffer: at low pH, the amine group will be protonated, while at high pH, the carboxylic acid is deprotonated. At the isoelectric point – characteristic for each aa – the aa exists as a zwitterion, and will not move (charges balanced). When satisfactory separation is complete, the aa can be sprayed with ninhydrin, and their isoelectric points can be compared.

Protein structure, paper chromatography: When a piece of chromatographic paper containing a small sport of the unknown aa is placed in an eluent, the eluent rises up the paper (capillary action). The different aa’s spread out to different extents, and move up the paper at different rate.

Proteins: Large macromolecules of chains of 2-amino acids. Formed by aa’s bonding to each other by peptide bonds. 1) The primary structure of the proteins is their strict sequence of aa residues. 			2) The secondary structure describes how the chain folds itself due to intramolecular hydrogen bonding (can be -helix -– hydrogen bonds within single chain, causing spiraling – or -pleated – hydrogen bonds between chains). 3) The tertiary structure describes overall folding of the chain, giving the protein its three-dimensional shape (may be due to hydrogen bonds, van der Waals’, and ionic attraction. Two Cys residues can form disulphide bridges). 			4) The quaternary structure results from the interactions between separate polypeptide chains. Uses of proteins: 1) Many are enzymes; 			2) can give structure; 3) source of energy; 			4) regulation hormones.

Pyranose: Six-membered monosaccharides such as glucose.

Retention factor: The ratio of the distance traveled by the sample to the distance traveled by the solvent in paper chromatography. Each aa has a specific Rf value.

Saccharide, mono-: Simple sugars. Empirical formula CH2O. Water soluble. Two families: 1) hydroxyaldehydes (contain aldehyde group and at least 2 OH groups. Reducing sugars); 			2) hydroxyketones (contain ketone group and at least 2 OH groups. Non-reducing sugars). Monosaccharides containing more than 5 C-atoms can make cyclic molecules.

Saccharide, oligo-: Containing 2-9 monosaccharides.

Saccharide, poly-: Polymers of monosaccharides. Formed by condensation reactions, forming glycosidic links.

Saponification: The process in which a triglyceride is hydrolyzed, forming soap. Reverse of esterification.

SH: Stimulating Hormone.

Soap: The sodium or potassium salt of the fatty acids produced from the saponification process. Functions because of hydrophilic head and hydrophobic tail. The tail dissolves in oil or grease to form a micelle. Surrounded by hydrophilic heads, which makes it soluble in water.

Starch: Polymer of -D-glucose. Exists in two forms: 1) amylose (water soluble); 			2) amylopectin (water insoluble). Most plants use starch as a store of carbohydrates.

Structure-function relationship: The structure of a chemical compound is adapted to its function by evolution.

Sucrose: Disaccharide in which -D-glucose and -D-fructose are joined by glycosidic link between the C1 from the glucose and the C2 from the fructose.

Synthetic detergents: Soap molecules of which the calcium or magnesium salts are soluble  that they can work well in hard water as well. Cause more pollution than soaps.

Triglyceride: Formed from condensation reaction between glycerol and fatty acids.

Vitamin A: Retinol. Found in cod liver oil, green vegetables and fruit. Fat soluble despite OH group, due to long hydrocarbon chain. Not broken down readily by cooking. Aids night vision. Retinol is oxidized to retinal in body. Retinal combines with protein opsin to form rhodopsin, the active agent for converting light signals into electrical signals that travel along optical nerve to brain. Deficiency  xerophtalmia or night-blindness.

Vitamin C: Ascorbic acid. Found in fresh fruit and vegetables. Water soluble. Involved in biosynthesis of the protein collagen (found in connective tissue). Deficiency  scurvy.

Vitamin D: Calciferol. Found in fish liver oils and egg yolk. Can be formed on surface of skin by UV light reacting with 7-dehydrocholesterol. Involved in uptake of Ca2+ and PO43+ ions from food, and in formation of bone structure. Deficiency  rickets.

Vitamins, fat soluble: A, D, E, F and K. Characterized by long non-polar hydrocarbon chains or rings.

Vitamins, water soluble: C and the 8 B’s. Contain NH or OH groups  has ability to hydrogen bond to water. Do not accumulate in body.

Vitamins: Vitamin D is the only vitamin that the body is capable of synthesizing. Can be defined as: 1) fat soluble or 2) water soluble. Vitamins containing C=C bonds and OH groups are readily oxidized. Refrigeration slows this process.

Water equivalent: The equivalent addition of energy to water as released when burning 1.00g of a food, causing a temperature increase.

Zwitterion: Ion with + and – charge. Aa’s exist as zwitterion at their isoelectric point.

Option B – Human Biochemistry - HL
Active site: The part of the protein that is involved in the catalysis.

ADP: Adenosine diphosphate. Made of base A, ribose, and two phosphate groups. Addition of another phosphate group makes ATP.

ATP: Adenosine triphosphate. Made up of base A, ribose, and three phosphate groups bonded together by high-energy phosphate bonds. Breaking the last of these bonds releases energy for use in cells, leaving ADP.

Chromosome: A structure composed of DNA and associated proteins.

Codon: Each of 64 permutations of the triplet code.

Coenzyme: Organic cofactors. Example: B-vitamins. Two types: 1) permanent coenzymes (always bonded to enzymes); 			2) non-permanent coenzymes (only bonded to enzymes during catalysis).

Cofactor: A substance that is a part of the active site, and that is involved in the catalysis. Can be: 1) inorganic (metal ions); 			2) organic (coenzymes).

Concentration, effect of: 1) Increasing concentration of the substrate: proportional increase in rate, but eventually evens out as all active sites of enzyme become saturated. 2) Increasing concentration of enzyme: proportional increase in rate.

Cyanide: A poison which works by blocking cytochrome oxidase, which is vital for aerobic respiration.

Cytochrome: Oxidizing enzymes in mitochondria. Contain Cu2+/Cu+.

Deoxyribose: The pentose sugar found in DNA.

DNA profiling: Using a small amount of cellular material, DNA is extracted and broken down into minisatellites using restriction enzymes. Splits where there are no coded messages in the base sequence are unique to the person giving the sample, and so this can be used to identify them.

DNA replication: DNA in cell begin to partly unzip as hydrogen bonds between the bases break. New sugar base units are taken up from the aqueous solution. Due to set pairs (AT and CG), the new strands will be identical to the original one.

DNA: Deoxyribonucleic acid. Double-stranded. Made up of nucleotides. Have – charge due to phosphate group. Cannot penetrate nucleus.

Electron transport: Occurs in inner membrane of mitochondria, which contains different proteins and enzymes, incl. cytochromes. The H+ ions from the NADH2 (product from the citric acid cycle) move along cytochromes by repeated redox reactions, due to presence of stronger oxidizing agents. Enzyme cytochrome oxidase causes H+ ions, e- and O2 to react to form water, releasing energy in the process.

Enzyme saturation: When all the active sites of the enzymes are occupied by a substrate. At this saturation, increasing substrate concentration has no effect.

Enzyme, factors affecting: 1) Enzyme concentration; 			2) substrate concentration; 3) temperature; 			4) pH; 5) inhibitors (reversible/irreversible).

Enzyme: Proteins that act as biological catalysts, for specific substrates.

Gene: A specific sequence of DNA which codes for the synthesis of a protein.

Glycolysis: First phase of breakdown of glucose in respiration. Occurs in cytoplasm.

Haemoglobin: Found in RBC’s. Contains four large polypeptide groups and four Fe2+ ions surrounded by hem groups. At high oxygen concentrations, oxygen bonds onto the iron in hem group as an extra ligand. At low concentrations, the reverse occurs. Hb

Heavy metal ions, effect of: Can poison enzymes by reacting with –SH groups replacing the hydrogen atom with a heavy metal atom or ion. Enzyme is denatured.

Induced fit theory: The active site can alter its shape to allow for a better fit with the substrate. An enzyme-substrate complex is created, and the catalyzed reaction takes place, leaving an enzyme-product complex. The products are released, and the enzyme reverts to its original shape.

Inhibition, competitive: Reversible inhibition. Resemble the substrate in shape, but cannot react. Slow down reaction by occupying active site. Does not affect Vmax but does affect Km.

Inhibition, irreversible: The inhibitor reacts with a part of the enzyme, and a covalent bond is formed between the inhibitor and enzyme. Enzyme activity is permanently destroyed. Example: nerve gases work by alkylation of an OH-group in the active site of an enzyme.

Inhibition, non-competitive: Reversible inhibition. Prevents enzyme reactions by binding to another part of the enzyme than the active site. This causes the enzyme to alter its shape and be unable to receive its substrate. Does not affect Km but does affect Vmax.

Inhibition, reversible: The inhibitor makes weak (intermolecular) bonds with the enzyme. The enzyme can become biologically active again. Two types: 1)competitive; 			2) non-competitive.

Metal ions: Examples of important ions: Na+ and K+ (nerve impulses and water balance); Ca2+ (bones and teeth); Cu2+ (enzymes); Co2+ (vitamin B12); Fe2+ (Hb). All depend on one of the following: 1) difference in charge density between two ions; 			2) variable oxidation states; 3) forming complexes with ligands.

Michaelis-Menten constant: The substrate concentration when the rate of the reaction is at ½ Vmax. The constant will always be the same for a particular enzyme and particular substrate. Km

mRNA: Messenger of genetic information (transcription).

Nucleotide: Repeating base-sugar-phosphate units that make up the nucleic acids. The base can be one of four nitrogen-containing bases, adenine (A), guanine (G), cytosine (C) or thymine (T). In RNA, uracil (U) replaces T. The phosphate bonds to the C4, while the base bonds to the C1.

pH, effect of: The pH value affects the tertiary structure. Enzymes have an optimum pH; outside of this, they can be denatured. More subtly, pH affects the electrostatic charge of the enzyme, which may affect the binding of substrate to enzyme, or the chemistry of the active site.

Phosphodiester bond: Bonding between nucleotides in a polynucleotide. Each nucleotide is joined between the C3 of the sugar and the neighboring phosphate group.

Phosphorylation: Addition of phosphate group. Phosphorylation in the sodium-potassium pump causes shape of pump to change.

Protein synthesis: Happens in ribosomes. 1) Transcription in nucleus; followed by 			2) processing by mRNA; 3) translation by ribosome.

Ribose: The pentose sugar found in RNA. Same as deoxyribose, except with an extra O bonded to the C2.

Ribosome: Particle that causes protein synthesis. Sequence of aa’s determined by nucleotide sequence in mRNA.

RNA: Ribonucleic acid. Single stranded. Contains base U instead of DNA’s base T. Two functions: 1) transcription (messenger of genetic information); 			2) translation (translating gene information into protein synthesis).

Sodium-potassium pump: Protein structure in cell membrane act as valves pumping Na+ ions out of cell and K+ ions into the cell. Works due to difference in charge density between Na+ and K+. The Na+ binds to three sites on the protein molecule. Energy is extracted from ATP by hydrolyzing to ADP, and the phosphorylation causes the pump to change its shape. Na + ions are expelled, and K+ ions bind to two sites on the protein molecule. The loss of the phosphate causes the pump to change its shape again, expelling the K+ ions into the cell.

Substrate: The substance on which an enzyme acts.

Temperature, effect of: Increasing temperature will initially increase rate of enzyme-catalyzed reactions (greater proportion of reactants will have the minimum activation energy). Optimum temperature for most enzymes is ca. 40C. Above this temperature enzymes rapidly denature.

Transcription: Copying of DNA onto a strand of RNA by unwinding temporarily due to the action of RNA polymerase. Takes place in nucleus.

Translation: The reading of the base sequence of the mRNA by ribosomes to make a sequence of aa’s to form a polypeptide.

Triplet code: A sequence of three bases that represents one aa.

tRNA: RNA that brings the right aa’s to the ribosomes.

Vmax: The maximum rate at which enzyme activity can occur, given a constant enzyme concentration. This is when the active sites of the enzyme are saturated.

Option D – Medicine and Drugs - SL
Addiction: Problem with opiates, in which a dependency on a drug is created.

Adrenaline: A naturally occurring hormone and stimulant. Released during stress. Responses:
 * Increased pulse;
 * dilation of pupils;
 * sweating;
 * diversion of blood to muscles;
 * decreased blood clotting time. Fat insoluble. Both amphetamine and adrenaline are based on the framework of a benzene ring with a two carbon chain and an amine (NH2 or NH) group at the end.

AIDS: Acquired Immune Deficiency Syndrome. Develops from HIV.

Alginates: Often combined with antacids. Prevent acid in stomach from rising into esophagus and causing ‘heartburn.’

Amine: Primary amines have one R group attached to N atom. Secondary have two on at least one N atom. Tertiary have three on at least one N atom.

Amphetamine: Fat soluble molecule which mimics noradrenaline. Similarity is so strong that it can replace noradrenaline in its storage sites, resulting in a flood of displaced noradrenaline molecules that bind to other neural proteins and set of a number of signals  euphoria.

Analgesic, mild: Have triad of properties: 1) analgesic (pain relief); 			2)antipyretic (fever reduction); 3) anti-inflammatory (reduces swelling). Believed that they work by blocking synthesis of prostaglandins.

Analgesic, strong: Analgesics that bind with specific chemical receptors in brain that receive pain messages  stopping the transmission of pain. They are almost all related to morphine. Family is called the opium alkaloids.

Analgesic: A drug which relieves pain without the aid of sleep. Two types: 1) mild; 			2)strong.

Antacids: Bases that neutralize excess acid. They are just barely soluble  neutralize gradually.

Antibiotics, broad spectrum: Antibiotics that are effective against a wide range of bacteria. This is initially prescribed until the specific diagnosis is found.

Antibiotics, narrow spectrum: Antibiotics only effective against certain types of bacteria. Prescribed once the specific diagnosis is found.

Anti-coagulant: Has blood-thinning properties.

Antivirals: Three possible approaches: 1) Trojan Horse (joins the replication process, inhibiting replication of the virus. Selectively toxic as it is activated by viral enzyme); 			2) Retrovirus inhibitor (inhibits RNA from acting as a template for DNA replication); 3) blunting (preventing escape of new viruses by inhibiting neuraminidase enzyme which cuts open cell membrane).

Aspirin: Derived from salicylic acid, which was unpleasant to use due to its acidity. The phenol group is substituted with an acetyl group in aspirin, but it is still acidic due to its alkanoic acid group. Has anti-coagulant properties, but there can be allergic reactions to it and it can induce Reye’s Syndrome in children, a potentially fatal liver and brain disorder.

Bacteria: Have slightly different structure to mammalian cells: have a cell wall. Penicillin prevents this wall from being made, and the internal pressures within the cell builds up and causes it to burst.

Benzodiazepenes: Class of depressants, including valium, prozac and mogadon. Benzodiazepenes work on chemical receptors in brain by binding to a special protein at the synapse of nerve junctions, causing gap between nerves to widen  prevents nerve cell from producing signal. The ethanol works on a different part of the same protein. The synergistic effect of these two working together can result in neural shutdown.

Blood-brain barrier: Can only by passed by fat soluble molecules.

Caffeine: A tertiary amine. Can 1) promote mild dependence; 			2) act as a mild diuretic; 3) increase anxiety (when taken in excess); 			4) cause insomnia. Known as respiratory stimulant, as it increases rate of respiration, by blocking inhibition of ATP. It does so by mimicking the shape of the ATP and causes the inhibiting enzyme to bind to it instead.

Cephalosporins: Variants of penicillin created to overcome the action of penicillinases. Broad spectrum antibiotics.

CNS: Central Nervous System.

Codeine: Derived from morphine by replacing H in one of alcohol groups with methyl group.

Depressant: Drugs which depress CNS by interfering with transmission of nerve impulses in the neurons. Effects depend on dosage: no effect  tranquilizing effect  sedative  sleep-inducing  lethal.

Designer drugs: Modifications to structure of natural drugs.

Dimethicone: An anti-foaming agent often used with antacids. Allow gas bubbles to coalesce and be expelled.

Drug administration: Five methods: 1) Oral (subjected to digestive process; easiest); 			2)Rectal (efficient, cultural biases); 3) inhalation (drug can only be absorbed through lungs); 			4) Parenteral (see PARENTERAL); 5) Patches (absorbed directly through skin barrier, allow absorption to take place gradually).

Drug development: A disease is selected, and targets along the disease process are identified, which may be vulnerable to interference by a drug. Lead molecules are considered, and selected according to the drugs which seem most effective, easiest to manufacture, have an advantage over existing drugs and are profitable. Phase I trials assess toxicology of drug. Phase II trials are clinical; the efficacy and dosage are determined. Phase III trials give the drug to thousands of closely monitored patients. If approved at this stage, drug is launched, after which comes the Phase IV trials, which is the post-launch monitoring of drug, which may lead to product extension.

Drug: A chemical which does one or more of the following: 1) alter mood or emotions; 			2) alter incoming sensory sensations; 3) alter physiological state.

Endorphins: Pain killers produced in the brain. Explain how people under great trauma feel little pain despite terrible injuries. Withdrawal symptoms of a heroin addict might be behavior of body without any endorphins at all.

Ethanol: Mild depressant in which side effect mask the main effect in moderate doses. Physiological effects: 1) decreasing inhibitions; 			2) short term reduction in reaction speed; 3) short term hangover; 			4) long term liver damage. Social and economic effects: 1) violent behavior; 			2) increase in car accidents; 3) absenteeism; 			4) cost of intensive medical care. The amount of alcohol that can be safely drunk depends on 			1) body mass; 			2) tolerance.

Gas chromatography: Test for ethanol. Under pressure, sample can be passed through thin tube containing inert material. Components of sample separate and can be identified.

Heroin: Derived from morphine by replacing H’s from both alcohol groups with acetyl (-COCH3) groups. More soluble in fatty tissue due to removal of both -OH groups.

HIV: Human Immunodeficiency Virus. Specific proteins on HIV bind to receptor protein on certain WBC’s called T cells. Quick mutation.

In vitro: Testing potency of molecule and selectivity; done in a laboratory environment.

In vivo: Meaning “in life.” Tests conducted in living species, to test for side effects and the effect of the body on the drug.

Intoximeter: Test for ethanol. Work by infrared spectroscopy, where the vibration of OH bond in ethanol can be detected.

LD50 value: The Lethal Dose of a substance that kills of 50% of a population. The lower the number the more toxic the substance.

Maximum daily tolerance: How much of a chemical can be taken into the body before undesirable symptoms occur. Related to rate at which body’s biochemistry is able to get rid of the same agent. Minimum doses should be used due to body’s increasing tolerance to drug.

Medicine: A drug used to cure a disease.

Nicotine: Sympathomimetic. Quickly reaches CNS. Short term effects: 1) Increased pulse and BP; 			2) reduction in urine output; 3) decrease in reflex times, 			4) increases concentration; 5) relieves tension. 		Long term effects: 			1) Risk of heart disease; 2) coronary thrombosis; 			3) peptic ulcers; 4) number of diseases, incl. lung cancer. 		Nicotine is a tertiary amine.

Noradrenaline: Variation of adrenaline which is produced in the brain. A neurotransmitter which sends signals to brain by binding with neural proteins.

Opiate: Cause addiction and lead to tolerance. Short-term effects: 1) euphoria; 			2) depression of CNS; 3) high doses  coma/death. 		Long-term effects: 			1) constipation; 2) loss of sex drive; 			3) social problems (e.g. theft, prostitution, etc).

Paracetamol: Has none of the side effects of aspirin given that the correct does is used. If doses are exceeded, it can induce massive liver damage. Acetaminophen.

Parenteral: Administering drugs by injection. Can be administered locally  reducing dose necessary and also possibility that body will alter molecular structure. Often required medically trained staff to administer. Three types: 1)intravenous (bypasses digestive system, quick arrival; still spreads out dose); 			2) subcutaneous (directly into body fat – only for fat soluble molecules); 3)intramuscular (into muscle tissue).

Pathogen: Organism or virus that causes disease.

Penicillin: Discovered by Alexander Fleming, who noticed that some of the bacteria in his petri dish had died off after some foreign appearance. Prevent cell walls from being made in bacteria; does not affect mammalian cells or viruses as they do not have a cell wall  selectively toxic. [Relatively] narrow spectrum antibiotic.

Penicillinases: New enzymes produced by bacteria to counter the action of penicillin. Degrade penicillin molecule.

Physiological state: Includes consciousness, activity level and co-ordination.

Placebo effect: A drug with no chemical effects. Used to test brain’s ability to influence physiology and to test the efficacy of new drugs.

Prostaglandins: Local action hormones which have a range of functions in body. One of these may be pyrogenic (raise body temperature). Also responsible for altering of signals across synapse junctions of nerves. Mild analgesics are believed to work by blocking the synthesis of these prostaglandins.

Retrovirus: Virus that contains RNA instead of DNA. Selective toxicity:''' The process of inhibiting processes vital to the pathogen, but absent in the host (see PENICILLIN).

Side effects: Unwanted effects of a drug. Risk-to-benefit ratio has to be considered. Thalidomide had an unacceptable ratio, while chemotherapy – causing hair loss and nausea – still has life-saving potential.

Stimulant: Drugs that increase a person’s state of mental alertness.

Sympathomimetic amine: Amines which mimic chemical behavior of hormones of the CNS.

Synergistic effect: Creating a cumulative effect greater than the sum of each individual effect. Benzodiazepenes have synergistic effect with ethanol. Ethanol also has synergistic effect with aspirin (may cause stomach bleeding).

Thalidomide: Morning sickness drug sold in many countries (1958-1962) until severe side-effects were discovered. Early clinical trials had shown no problems. Later withdrawn, but many children had been born with absent or malformed limbs (phocomelia). Currently used for treatment of some cancers, leprosy and other conditions where its inhibition of blood vessel formation is beneficial.

Tolerance: The body’s adaptation to the action of a drug, resulting in a requirement for larger doses to achieve original effect.

Toxicology: Poisonous effect of drug.

Trial, blind: A trial of drugs where half of the patients are given the real drug and the other half a placebo. The administering doctors know which patient receives which drug.

Trial, double blind: Similar to blind trial except that neither the administering doctor nor the patient knows which patient receives which drug.

Virus: Contains DNA but cannot replicate by itself. Works by sticking to the outside of a cell, and inject its own DNA, effectively causing cell to replicate the virus for it. New viruses break through cell and infect other cells. All viruses have a central core of DNA or RNA surrounded by a capsid of regularly packed protein units (capsomeres). Have no nucleus or cytoplasm.

Option D – Medicine and Drugs - HL
Anesthetic, general: An anesthetic that renders the patient unconscious so that they can feel no pain. First anesthetic to be used was ether. This was highly inflammable, so later chloroform and nitrous oxide (laughing gas) was used. Chloroform was found to possibly lead to liver damage, while nitrous oxide was not very efficient. Objectives for anesthetic: 1) able to put patient to sleep; 			2) non-toxic; 3) non-inflammable; 			4) volatile; 5) stable. 		Halothane was found to satisfy these requirements, but it is a CFC, which can cause damage to ozone layer.

Anesthetic, local: An anesthetic that blocks pain in a specific area without affecting overall level of consciousness.

Cannabis, arguments for/against: 		1) Cannabis addictive: contested. 			2) May lead to harder drugs. 3) Toxic. 			4) If cannabis legalized  demands to legalize other drugs. 5) Should be legalized to remove profits from criminals. 			6) Ensure correct dosage.

Chiral auxiliary: The main component of a technique used to obtain only a desired enantiomer. Attaching an auxiliary which is itself optically active creates the stereochemical conditions for the reaction to form only one enantiomer.

Cisplatin: Cis form of a chemical which is highly effective in the treatment of testicular and ovarian cancers. Transplatin is not as effective an anti-cancer drug. Causes alteration in the cancer cell’s DNA  cannot replicate properly.

Cocaine: First anesthetic to be used. Work by suppressing nerve transmissions. Side effects: 1) anxiety; 			2) nausea; 3) headaches; 			4) possible coma/death.

Combinatorial library: A technique to form a library of combinations of aa or other types of active molecules, by use of mix and split process.

Form, cis-: Geometric isomer where the similar groups are on the same side.

Form, trans-: Geometric isomer where the similar groups are on different sides.

Hallucination: Distortions in sound and visual perceptions.

Hallucinogen: Causing hallucinations.

Indole ring structure: A common structure in many hallucinogenic drugs such as LSD and psylocybin.

Isomers, geometric: Stereoisomerism where the isomers differ in positions of a group relative to the double bond.

LSD: Does not occur naturally. Believed to work by blocking serotonin, one of the compounds responsible for transmitting impulses across synapses in brain. Short term effects: 1) restlessness; 			2) dizziness; 3) hallucinations. 		Long term effects: 			1) severe depression; 2) recurrences of LSD effects (flashbacks).

Marijuana: Cannabis when dried. Not based on indole ring. Causes feeling of relaxation and enhanced auditory and visual perception. Synergistic effect with depressants. Long term effects: 1) apathy; 			2) lethargy (state of sluggishness); 3) reduced fertility.

Mescaline: One of oldest known hallucinogens. Causes hallucinations, and decrease in appetite. Synergistic effect with alcohol.

Mix and split: Coupling resulting in a combination of active molecules. Gives all permutations possible.

Partial pressure: The pressure a gas would exert if it occupied the total volume on its own. Found by mole fraction of gas multiplied by total pressure.

Procaine and lidocaine: Derivatives of cocaine.

Psilocybin: Mildly hallucinogenic. Tolerance may develop but it is not addictive. Biggest danger lies in inability to recognize “magic mushrooms” correctly; similar looking fungi are poisonous.

Racemic mixture: A mixture containing equal amounts of both enantiomers.

Thalidomide: One enantiomer helped against morning sickness, while the other was responsible for causing fetal deformities.

Virtual library: Modeling permutations virtually.

title: IB Chemistry/Option Definitions


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Talk:Basic Computing Using Windows/Computers and Peripherals

Figures
Note: Find/Create and Upload images for the figures in this chapter. --Singpolyma 12:51, 27 September 2005 (UTC)
 * The following items cannot be uploaded from the original source (due to licencing violations) and were not present on the Wikimedia Commons. Suitable images with appropriate licences need to be found for these figures:
 * Figure 1.2 - A computer box
 * Figure 1.3 - An LCD monitor
 * Figure 1.7 and the corrosponding paragraph should be updated to the Windows XP welcome screen

Some figures were deleted from the commons due to licensing issues with screenshots... I hope to resolve this shortly. -- SingpolymaT E 06:53, 29 September 2005 (UTC)


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Basic Computing Using Windows/Operating Systems and Controls

Software

Software is the set of instructions that tell a computer what it needs to do.

There are two kinds of software: the System Software which includes the Operating System and Applications Software.

Operating System

Abbreviated OS, the Operating System is the resource manager which transforms sectors, bytes, interrupts and ports into files, folders, processes, and the user-interfaces with which you can interact. Examples include: Microsoft Windows (XP, Vista, or 7), any flavor of Linux, and Mac OS X (An apple version of Unix).

Applications Software

Also called user programs, pieces of applications software do the specific things you want.

The Operating System runs the computer and the Applications Software. It makes sure that the Hardware and the Applications Software understand each other. This makes it the most important piece of software on the computer. The Operating System also comes with utilities. These are pieces of Applications Software that mostly deal with managing data. You can also buy Third Party utilities, which means a different company made them than made the Operating System.

Utilities Programs that manage, repair, and optimize data on a computer. A basic set comes with every OS.

Applications Software does the specific things you want the computer to do, Whereas the Operating System is general instructions to the computer for controlling the Hardware, Applications Software is specific instructions that work together with the Operating System to do work for you.

There are as many different kinds of Applications Software as there are things you could want to do with a computer, however the most common are word processing, spreadsheet, presentation, and database software and all computer games. Word processing software is used to create documents, which are formatted pages of text, such as letters, memos, reports or essays. Spreadsheet software organizes data, usually numbers, into columns and rows. It is used mostly for accounting and has many features for doing mathematical operations. Presentation software is used to make virtual (or, simulated) slide shows and usually have all sorts of exciting features for animations and sounds that you just can’t do in a normal slide show. Database software is an advanced way of organizing complicated information in simple formats. A database is your electronic filing cst OS's and programs have the same features whether they use Windows or not, but all computers running Windows will have these features with these names. The thing we did in the last chapter with the box that comes up when you turn on your computer is called logging in. The screen you see after logging in is called the Desktop. Most things on a computer are named after things in real life, and they are usually used similarly too. Just like a real desktop the desktop on a computer is where you go to access all your data. However, a real desktop has a flat horizontal surface.

You can replace the Operating System with another whether or not your system gets a virus. The most common replacement Operating System is called Linux. It is free to download and install and software for it is freely available via the Internet.

Desktop The desktop is the area that appears right after logging in. It contains a background picture (wallpaper),icons and the taskbar.

On the desktop are pictures with text labels under them, these pictures are called icons because they represent something else. If you move or get rid of an icon, all that means is that you have to access what they represent a different way, you haven’t gotten rid of the application software the icon is representing. Icons usually represent programs, but sometimes they represent collections of data. Double-clicking (clicking twice in rapid succession) on one of these icons will open whatever it represents, the text tells you what it represents.

Icons A tiny picture that represents a program, folder, or program function.

There is a bar that is usually at the bottom of the desktop, however it may also be on any other side. If you cannot see it, then move the cursor to the edge where it is and it will come up. It is called the task-bar.

Taskbar The taskbar is the bar along one side of the desktop. It is used for launching programs or opening the window of an open program.

Along the main part of the task-bar is a list of all open programs, clicking on one element of this list will put that program’s window (the box that a program is viewed in) on top of all other open windows. Over on one side of the task-bar is a clock; beside the clock are a bunch of icons that represent open ‘invisible’ programs. These are programs that are always running and do things ‘behind the scenes’. This area is called the system tray. On the main part of the task-bar there is sometimes a small group of icons, this is called the quick-launch bar. Clicking on one of these icons opens whatever it represents.

System Tray The system tray holds icons for programs currently running ‘behind-the-scenes’.

On the opposite side of the task-bar from the clock and the system tray is a button. A button (or command button) is just like a real button, when it is pushed (clicked) it does something. Some buttons have text on them that say what they do, and some have icons representing what they do. Some have both.

(Command) Buttons Buttons do something when you click on them. They may be labeled by text, an icon, or both.

The quick-launch icons are also buttons. Some buttons are raised to look like real buttons and some only raise up when you hover (put the cursor on top of) them. The button on the other side of the start-bar from the clock and system tray is called the start-button. When you click the start-button it opens the start-menu. The start-menu has icons for more programs and data collections, although it is usually programs.

Start button The Start button is a button that opens the start-menu.

Start menu The Start menu contains icons for all installed programs and data collections, usually for programs.

The icons that are on the desktop, the quick-launch bar, and the start-menu are usually shortcuts. On the desktop shortcuts are often indicated by a small symbol on top of the icon. Shortcuts are what I meant earlier when I said ‘if you move or get rid of an icon, all that means is that you have to access what they represent a different way, you haven’t gotten rid of the actual thing’. Icons represent all data collections and programs even if they are not shortcuts, however normally the ones on the desktop and in the start-menu are shortcuts.

Shortcuts Icons that are only links to the things those icons represent.

The difference between icons and shortcuts is important so be sure you understand it. An icon is any picture that is meant to convey what something is. The icon on the start-button represents the fact that it is a major part of Windows, which is why it is a Windows logo. Shortcuts are a link to a program or data collection; the icon on a shortcut represents whatever the shortcut opens, however the same icon would be on the real thing as well. A Venn Diagram can maybe better show this, see Figure 2.2.

You open whatever is linked to by each shortcut on the start-menu by clicking on it. If any icon has a right-arrow beside it, then hovering over it or clicking on it will make a sub-menu (a menu inside a menu) come out with more shortcuts on it.

Everything we just talked about is part of the Windows interface. An interface is just anything that goes between two or more things. This interface goes between you and the computer, you could also say that the Operating System is the interface between the hardware and software.

Interface An interface, just as the name suggests, is anything that acts as or creates a medium of interaction or communication between multiple things. A user-interface is the means of interaction between (you)the user and the computer.

There are some standard things that are on most user-interfaces. We have already talked about one, buttons. These things are called controls. Below is a table of some of the more common controls, starting with buttons:

You can get a basic description of what any control does by hovering your mouse over it. A little thing with text will pop up. This is called a tool-tip (or a ToolTip).

Besides these there are also menus. Menus all operate the same way as the start-menu. Some of them are found at the tops of programs. These are called main-menus or simply menus. Other menus are opened by right-clicking (pushing the right mouse button over something). These are called popup-menus.


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Talk:Basic Computing Using Windows/Operating Systems and Controls

The figures for this chapter need to be found/created/uploaded and images need to be inserted into the controls table. --Singpolyma 13:26, 27 September 2005 (UTC)

Learning Somthing New
Thank you for this format. A easy read and comprehesive way to computers


text:
Talk:Basic Computing Using Windows

Introduction
This book is intended to be a basic introcuction to Computers for newbies, focusing on Windows simply because that is the most common Operating System. The initial content is adapted from a textbook I wrote to teach a course at a local school where I live, it is my own content and has never been published and thus would be under my copyright, so I have the right to release it as I choose and am relicensing it here as per Wikibook's licensing restrictions. Vocabulary/Glossary words on the subpages are currently in bold and should eventually be links to their section of the (as yet nonexistant) glossary or to Wiktionary. --Singpolyma 13:33, 27 September 2005 (UTC)
 * While this is meant to be a general introduction to computing, the focus on a particular OS is necessary. The attempt has been made to keep the instructions compatable with Windows 9x and XP both, however in an attempt to keep things simple this often led to confusing wordings in the text.  This needs to be remedied, especially in light of the forthcoming Windows Vista which will add yet another dimension to the text. -- Singpolyma 13:55, 28 September 2005 (UTC)
 * As this book is focused on computer beginners, wouldnt it be better to not worry so much about compatability with the Win9x kernel series? WinNT kernel has been the standard for a few years now, and no new versions of Win9x are even in development. Tricky wording can be reduced by removing all information from past Windows versions into an appendix. --Whiteknight 14:03, 28 September 2005 (UTC)
 * I suppose that's true. Originally compatability was maintained (in my 'initial' copy) because at the school I taught at all the computers run Win 9x.  However most computer beginners would be using WinXP (or Vista, soon), so I suppose that the text should probably be reworked to focus on those and then maybe and introductory note somewhere stating that the important things different in operating older versions of Windows are in an appendix. -- SingpolymaT E 15:15, 28 September 2005 (UTC)

TOC on main page
I moved the TOC to the main page for user conveniance, a seperate TOC page is not really needed at this point. --Singpolyma 10:14, 28 September 2005 (UTC)

TOC as template
the TOC actually makes more sense as a template, so that's what it is now -- Singpolyma 12:19, 28 September 2005 (UTC)

Computers for Beginners
How does this differ from the book that already exists, Computers for Beginners? --68.148.190.38 04:20, 4 October 2005 (UTC)

System Maintance
How about a system maintance section; basics such as: Defrag, cleaning temp files, etc.

Security
Either in this book or in Computers for Beginners, would it be a good idea to include a chapter on security? Anti-virus, anti-spyware, anti-rootkit, the need to keep secuity software signature files up to date, software firewalls, Microsoft security updates, the common email scams, phishing attacks, etc? John259 (talk) 17:14, 2 March 2008 (UTC)

Backups
Either in this book or in Computers for Beginners, would it be a good idea to include a chapter on008 (UTC)

Featured Book Status removed
Per the discussion at Featured books/Nominations/Removal/Basic Computing Using Windows, this book is no longer a Featured Book. For advice on how to restore it to Featured Book status in the future please see the discussion at the link above. --ЗAНИA talk 11:34, 15 November 2016 (UTC)

Economics
Monopoly Madiope Moss (discuss • contribs) 17:19, 5 August 2018 (UTC)

title: Talk:Basic Computing Using Windows