1
Q
what is conservation of energy
A
energy is neither created nor destroyed but changed from one form to another
2
Q
what are standard conditions?
A
298k
1atm
3
Q
enthalpy of formation(^hf):
A
- exothermic
- enthalpy change when one one mole of a substance is formed from its elements in their standard states
4
Q
enthalpy of combustion(^Hc):
A
enthalpy change when one mole of a substance undergoes complete combustion in oxygen.
5
Q
Ionisation enthalpy (^Hie) first:
A
- endothermic
- enthalpy change when one mole of gaseous atoms loses one electron per atom to produce gaseous 1+ ions.
e.g: Na(g) ———-> Na+(g) + e-
6
Q
Ionisation enthalpy second:
A
when one mole of gaseous 2+ ions is produced from one mole of 1+ ions.
7
Q
electron affinity first:
A
- exothermic
- produces 1 mole of gaseous ions with a -1 charge
cl(g) + e- -> cl-(g)
8
Q
electron affinity second:
A
- endothermic
- when one mole of gaseous 1- ions gains one electron to produce gaseous 2- ions.
9
Q
enthalpy of atomisation(^Hat):
(solids and gases)
A
- endothermic
- when one mole of gaseous atoms is produced from an element in its normal state.
10
Q
Hydration enthalpy:
A
- exothermic
- producing 1 mole of aq ions from one mole of gaseous ions
11
Q
enthalpy of solution:
A
when an ionic solid dissolves producing an aqueous solution.
Nacl(s) + aq ——> Na+(aq) + cl- (aq)
12
Q
Lattice enthalpy of formation:
A
- exothermic
- when 1 mole of an ionic compound is formed from its gaseous ions
13
Q
Lattice breaking:
A
- endothermic
- breaking 1 mole of an ionic compound into its gaseous ions
