AQA A LEVEL Chemistry
Study online at https://quizlet.com/_3g99ba
1. Relative atomic mass The average mass of an atom of an element, relative to 1/12th of the
mass of an atom of Carbon-12
2. Relative molecular mass Average mass of a molecule compared to 1/12th of the mass of a
carbon-12 atom
3. The Avogradro constant the number of particles in a mole
4. ideal gas equation pV = nRT
5. empirical formula the simplest whole number ratio of atoms of each element in a
compound
6. percentage atom econo- (Mass of desired product/total mass of reactants) x 100
my
7. ionic bonding the electrostatic attraction between oppositely charged ions in a lat-
tice
8. covalent bond a shared pair of electrons between non-metal elements
9. co-ordinate bond a shared pair of electrons where both electrons are supplied by one
atom
10. repulsion in shapes of Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding
molecules pair
11. electronegativity the power of an atom to attract the pair of electrons in a covalent bond
12. hess' law Total enthalpy change for a reaction is independent of the route
chosen
13. mean bond enthalpy The energy required to break a covalent bond into gaseous atoms
averaged over different molecules
, AQA A LEVEL Chemistry
Study online at https://quizlet.com/_3g99ba
Bonds broken - bonds made
14. activation energy The minimum amount of energy needed to start a chemical reaction
15. catalyst A substance that increases the rate of a chemical reaction without be-
ing changed by providing an alternative reaction pathway by lowering
activation energy
16. Le Chatelier's principle When a system in dynamic equilibrium is subjected to change, the
position of equilibrium will shift to oppose the change.
17. oxidising agents electron acceptors
18. reducing agents electron donors
19. Enthalpy of formation Enthalpy change when one mole of a compound is formed from
its constituent elements under standard conditions in their standard
states
20. Enthalpy of atomization The energy required to produce one mole of gaseous atoms from an
element in its standard state
21. Electron affinity the enthaply change when one mole of gaseous atoms forms one
mole of -1 ions
22. Lattice enthalpy of for- Enthalpy change when one mole of a solid ionic compound is formed
mation from its constituent ions in the gas phase
23. Lattice enthalpy of disso- Energy change when 1 mol of an ionic lattice dissociates to its gaseous
ciation ions.
24. standard electrode po- 298K
tential 100kPa
1.00moldm-3
Study online at https://quizlet.com/_3g99ba
1. Relative atomic mass The average mass of an atom of an element, relative to 1/12th of the
mass of an atom of Carbon-12
2. Relative molecular mass Average mass of a molecule compared to 1/12th of the mass of a
carbon-12 atom
3. The Avogradro constant the number of particles in a mole
4. ideal gas equation pV = nRT
5. empirical formula the simplest whole number ratio of atoms of each element in a
compound
6. percentage atom econo- (Mass of desired product/total mass of reactants) x 100
my
7. ionic bonding the electrostatic attraction between oppositely charged ions in a lat-
tice
8. covalent bond a shared pair of electrons between non-metal elements
9. co-ordinate bond a shared pair of electrons where both electrons are supplied by one
atom
10. repulsion in shapes of Lone pair-lone pair > lone pair-bonding pair > bonding pair-bonding
molecules pair
11. electronegativity the power of an atom to attract the pair of electrons in a covalent bond
12. hess' law Total enthalpy change for a reaction is independent of the route
chosen
13. mean bond enthalpy The energy required to break a covalent bond into gaseous atoms
averaged over different molecules
, AQA A LEVEL Chemistry
Study online at https://quizlet.com/_3g99ba
Bonds broken - bonds made
14. activation energy The minimum amount of energy needed to start a chemical reaction
15. catalyst A substance that increases the rate of a chemical reaction without be-
ing changed by providing an alternative reaction pathway by lowering
activation energy
16. Le Chatelier's principle When a system in dynamic equilibrium is subjected to change, the
position of equilibrium will shift to oppose the change.
17. oxidising agents electron acceptors
18. reducing agents electron donors
19. Enthalpy of formation Enthalpy change when one mole of a compound is formed from
its constituent elements under standard conditions in their standard
states
20. Enthalpy of atomization The energy required to produce one mole of gaseous atoms from an
element in its standard state
21. Electron affinity the enthaply change when one mole of gaseous atoms forms one
mole of -1 ions
22. Lattice enthalpy of for- Enthalpy change when one mole of a solid ionic compound is formed
mation from its constituent ions in the gas phase
23. Lattice enthalpy of disso- Energy change when 1 mol of an ionic lattice dissociates to its gaseous
ciation ions.
24. standard electrode po- 298K
tential 100kPa
1.00moldm-3
