definitions p1

Question 1

relative isotopic mass

Answer 1

mass compared with 1/12th mass of carbon-12

Question 2

relative atomic mas

Answer 2

weighted mean mass compared with 1/12th mass of carbon-12)

Question 3

first ionisation energy

Answer 3

removal of 1 mol of electrons from 1 mol of gaseous atoms

Explanation to include the small decreases as a
result of s- and p-sub-shell energies (e.g. between
Be and B) and p-orbital repulsion (e.g. between N
and O).

Question 4

enthalpy change of formation

Answer 4

formation of 1 mol of a compound from its elements,
∆fH

Question 5

enthalpy change of combustion

Answer 5

complete combustion of 1 mol of a substance, ∆cH

Question 6

enthalpy change of neutralisation

Answer 6

formation of 1 mol of water from neutralisation, ∆neutH

Question 7

average bond enthalpy

Answer 7

as the breaking of 1 mol of bonds in gaseous molecules

Question 8

lattice enthalpy

Answer 8

formation of 1 mol of ionic lattice from gaseous
ions, ∆LEH

Question 9

enthalpy change of solution

Answer 9

dissolving of 1 mol of solute, ∆solH

Question 10

enthalpy change of hydration

Answer 10

dissolving of 1 mol of gaseous ions in water, ∆hydH)