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114 Cards in this Set
- Front
- Back
Atomic number (proton number) |
The number of protons in the nucleus of an atom.
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Mass number (nucleon number) |
The number of protons plus neutrons in the nucleus of an atom. |
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Isotopes |
Atoms of the same element with a different number of neutrons |
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Relative isotopic mass |
The mass of an atom of an isotope compared with 1/12 of the mass of an atom of carbon-12. |
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Relative atomic mass |
The weighted mean mass of an atom of an element compared with 1/12 of the mass of an atom of carbon-12. |
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Acid |
A proton (H+) donor |
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Base |
A proton (H+) acceptor |
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Strong acid |
Completely dissociates into its ions in aqueous solution |
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Weak acid |
Partially dissociates into its ions in aqueous solution |
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Alkali |
Base that dissolves in water and releases OH- ions in aqueous solution |
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Salt |
A salt is produced when the H+ ion of an acid is replaced by a metal ion or NH4+. |
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Atomic orbital |
A region within an atom that can hold up to two electrons with opposite spins. |
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First ionisation energy |
The energy required to remove one electron from each atom in one mole of gaseous atoms to form one mole of gaseous 1+ ions |
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Successive ionisation energies |
A measure of the energy required to remove each electron in turn. |
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Mole |
The amount of substance containing as many particles as there are carbon atoms in exactly 12g of carbon 12. |
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Molar mass |
The mass, in grams, per mole of a substance. Units- gmol-1 |
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Mass (g) = |
Moles x Molar mass (RFM) |
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The Avogadro constant |
The number of particles in 1 mole of any substance is equal to 6.02 x10^23 |
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Hydrated |
When water of crystallisation is present in a crystal compound. |
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Anhydrous |
When all the waters of crystallisation have been removed from a compound.
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Water of crystalliation |
The water present in a compound giving the compound a crystalline appearance ( the x.H2O term) |
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Ionic bonding |
The electrostatic attraction between oppositely charged ions |
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Covalent bonding |
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms. |
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Dative covalent (coordinate) bonding |
The strong electrostatic attraction between a shared pair of electrons and the nuclei of the bonded atoms, where only one of the atoms supplies both of the electrons shared. |
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Average bond enthalpy |
Average bond enthalpy can be used as a measurement of covalent bond strength. |
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Molar gas volume |
Molar gas volume at r.t.p 24.0 dm3 mol-1 1 mol of any gas = 24.0dm3 (24,000cm3) |
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Ideal gas equation |
p V = n R T |
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Reacting moles in solution equation |
Moles = concentration x volume |
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The shape of a molecular ion is determined by... |
-The number and type of electron pairs in the outer shell of the central atom. Electron pairs repel other electron pairs, as far apart as possible. |
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Electronegativity |
The ability of an atom to attract the bonding electrons towards itself in a covalent bond. |
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Metallic bonding |
The attraction of a lattice of positive ions to a 'sea' of delocalised electrons |
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Ionic compounds |
The solid structure of a giant ionic lattice results from the regular arrangement of oppositely charged ions strongly attracted in all directions |
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Simple covalent compounds |
Structures made up of small, simple molecules with weak forces of attraction between the molecules. |
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Giant covalent structures |
Soldis which are networks of atoms bonded together by strong covalent bonds. |
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Oxidation number/state |
A measure of the number of electrons that the atom uses to bond with atoms of another element. |
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Redox |
A reaction where both oxidation and reduction take place |
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Oxidation |
The loss of electrons/ increase in oxidation number |
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Reduction |
The gain of electrons/ decrease in oxidation number |
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Hydrocarbons |
A compound that contains only carbon and hydrogen |
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Homologous series |
A family of compounds containing the same functional group but with each successive member of the series differing by a CH2 group |
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Functional group |
An atom/group responsible for the characteristic reactions of the compound |
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Aromatic compounds |
Compounds containing a benzene ring with formula C6H6 |
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Aliphatic compounds |
Compounds of hydrogen and carbon joined together in straight chains, branched chains and non- aromatic rings. |
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Alicyclic compounds |
Aliphatic compounds arranged in non-aromatic rings, with or without side chains. |
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General formula |
The simplest algebraic formula for any member of a homologous series |
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Displayed formula |
This shows all the the bonds and how all the atoms are joined together in the structure. |
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Structural formula |
This shows minimum detail required for the arrangement of atoms in a molecule. The carboxyl group is represented as COOH and the ester group as COO |
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Skeletal formula |
This 'hides' ever carbn atom and any H atom which is directly attached to a C atom. This leaves just the carbon backbone and any functional groups |
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Structural isomers |
Molecules with the same molecular formula but a different structural formula |
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Homolytic fission |
The breaking of a covalent bond where one electron from the bonding pair goes to each atom to form 2 radicals |
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Heterolytic fission |
The breaking of a covalent bond where both electrons from the bonding pair go the the same atom to form 2 ions |
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Addition reaction |
Two molecules react to make one product. One molecule adds across the double bond of an unsaturated molecule to make a saturated molecule |
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Substitution reaction |
A reaction where an atom/group is replaced by another atom/group |
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Elimination reaction |
An atom/group is removed from a saturated molecule to make an unsaturated molecule |
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Oxidation reaction |
Oxygen is added and/or hydrogen is removed from a molecule |
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Condensation reaction |
A reaction where a H2O molecule is lost when two molecules join together |
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Alkanes |
Saturated hydrocarbons
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C-C and C-H bonds |
They're made up of a sigma bond |
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Sigma bond |
Formed between 2 carbon atoms or a carbon and hydrogen atom by a single axial overlap of orbitals. This allows free rotation of the sigma bond |
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Radical substitution |
This is a substitution type reaction because a H atom in the alkane molecule is replaced by a halogen atom. |
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Radical |
A species with an unpaired electron |
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Percentage yield |
A measure of the efficiency of converting reactants into products |
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Yield |
The mass of a product obtained from a reaction |
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% yield equation |
(actual mass of product/ theoretical mass of product) x 100 |
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Second % yield equation |
(actual mol of product/ theoretical mol of product) x 100 |
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Atom economy |
A measure of how much of the total mass of reactants is converted into the desired product |
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Atom economy equation
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(Mr of desired product/Mr of total product) x 100 |
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What forms a carbon double bond? |
A sigma and a pi bond |
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Pi bond |
Formed by the double, sideways overlap of p orbitals above and below the bonding carbon atoms |
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Stereoisomers |
Compounds with the same structural and molecular formula but with a different arrangement of the atoms in space |
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Criteria for E/Z isomerism |
Must have a C-C double bond because this can't rotate Each carbon atom of the C-C double bond must have 2 different groups attached to it |
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Criteria for cis/trans stereoisomerism |
Must have a C-C double bond because this can't rotate. Each carbon of the C-C must have 2 different groups attached to it. Two groups must be the same, one on each C of the C-C double bond |
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Z (cis) isomer |
Has the same groups on the same side |
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E (trans) isomer |
Has the same groups diagonally opposite |
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Chemical test for the alkene functional group |
Add bromine. bromine water and shake.
If bromine is decolourised(from orange to colourless) the compound is an alkene. If the bromine is not decolourised, the compound is not alkene. |
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Electrophile |
An electron pair receptor |
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Curly arrow model |
A curly arrow shows the movement of an electron pair, to either make or break a covalent bond |
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Enthalpy change |
The amount of heat released (or absorbed) by a chemical reaction, carried out at constant pressure. Units: kJ mol-1 |
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Exothermic reaction |
A reaction where heat energy is released to the surroundings. ∆H is negative. |
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Endothermic reaction |
A reaction where heat energy is absorbed from the surroundings. ∆H is positive. |
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Average bond enthalpy ∆HθE |
The average enthalpy change when 1 mole of gaseous bonds are broken by homolytic fission |
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Standard conditions |
Temperature-25 degrees c (298K) Pressure- 1atm (100kPa) Solutions must have a concentration = 1.0 mol dm-3 |
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Standard enthalpy change of a reaction ∆HθR |
The enthalpy change that accompanies a reaction in the molar quantities expressed in a chemical equation under standard conditions, all reactants and products being in their standard states. |
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Standard enthalpy of neutralisation ∆Hnθ |
The enthalpy change that accompanies the neutralisation of an aqueous acid by an aqueous base to form 1 mole of H2O (l) under standard conditions.
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Standard enthalpy change of formation ∆HθF |
The enthalpy change when 1 mole of a compound is formed form its constituent elements in their standard states, under standard conditions.
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Standard enthalpy change of combustion ∆HθC |
The enthalpy change when one mole of a substance reacts completely with oxygen under standard conditions, all reactants and products being in their standard states. |
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Hess's law |
The enthalpy change of a reaction depends only on the initial and final states and is independent of the route taken. |
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Rate of reaction |
The rate of a chemical reaction is the change in concentration of a reactant or a product per unit time. |
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Activation energy |
The minimum energy required to start a reaction by the breaking of bonds in the reactants |
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What does a catalyst do? |
It increases the rate of reaction and is not consumed(used up) by the overall reaction. |
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Heterogeneous catalysis |
Catalysis of a reaction in which the catalyst has a different physical state from the reactants( frequently, reactants are gases while the catalyst is a solid) |
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Homogeneous catalysis |
Catalysis of a reaction in which the catalyst and the reactants are in the same physical state( frequently the aqueous or gas state) |
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How does a catalyst work? |
A catalyst the increases rate of reaction by providing a different pathway (mechanism) for the reaction which has a lower activation energy |
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Reaction taking place on a catalytic converter |
2NO(g)+2CO(g)-->N2(g)+2CO2(g) |
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Adsorption |
The CO and NO molecules adsorb to the catalyst surface, The bonds within the molecules weaken. The activation energy is lowered |
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Chemical reaction |
Bonds broken in the CO and NO reactant molecules. New bonds formed to make CO2 and N2 products |
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Desorption |
The CO2 and N2 products desorb from the catalyst surface. |
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Oxidising power of a halogen |
A measure of the strength with which a halogen atom is able to attract and capture an electron to form a halide ion |
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Displacement reaction |
A reaction in which a more reactive element displaces a less reactive element from an aqueous solution of its halide ions |
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Nucleophile |
An electron pair donor |
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Disproportionation reaction |
A reaction in which the same element is both oxidised and reduced |
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Dehydration |
A reaction where a H2O molecule is removed from a saturated to an unsaturated molecule. |
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Reversible reaction |
A reaction mad up of a forward reaction and a reverse reaction. |
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Dynamic equilibrium |
This exists in a closed system when the rate of the forward reaction is equal to the rate of the reverse reaction. |
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Characteristics of dynamic equilbrium |
Rate of forwards=rate of reverse Closed system Concentrations remain constant Macroscopic properties do not change |
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Le Chatelier's principle |
When a system in dynamic equilibrium is subjected to a change, the position of equilibrium will shift to minimise the change |
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Curly arrow |
The movement of an electron pair, showing either heterolytic fission of, or formation of, a covalent bond |
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Hydrolysis |
A chemical reaction involving water, or an aqueous solution, which causes the breaking of a bond, splitting a reactant molecule into two products
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Volatility |
The ease with which a liquid turns into a gas |
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Precipitate |
An insoluble solid formed when two solutions are mixed together |
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Solution |
A homogeneous mixture composed of two or more substances. A solution consists of a solute and solvent. |
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Solute |
The substance that is dissolved in the solvent |
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Distillation |
The technique of heating a liquid to create vapour which is collected when cooled and condensed, separate from the original liquid. |
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Heat under reflux |
The continuous boiling and condensing of a liquid, in a condenser, preventing loss of volatile liquids from a heated reaction vessel |