3.1.8 Thermodynamics

Question 1

(ΔHf)

Answer 1

Enthalpy of formation
The enthalpy change when 1 mole of a compound is formed from its elements
in their standard states.

Question 2

(ΔHdiss)

Answer 2

Enthalpy of dissosciation
The enthalpy change when all the
bonds of the same type in 1 mole of
gaseous molecules are broken.

Question 3

(ΔHat)

Answer 3

Enthalpy of atomisation
The enthalpy change when 1 mole of
gaseous atoms is formed from an
element in its standard state.

Question 4

(ΔHie1)

Answer 4

First ionisation energy
The enthalpy change when 1 mole of
gaseous 1+ ions is formed from 1 mole of gaseous atoms.

Question 5

(ΔHie2)

Answer 5

2nd ionisation energy
The enthalpy change when 1 mole of
gaseous 2+ ions is formed from 1 mole
of gaseous 1+ ions.

Question 6

(ΔHea1)

Answer 6

1st electron affinity
The enthalpy change when 1 mole of
gaseous 1- ions is made from 1 mole of
gaseous atoms.

Question 7

(ΔHea2)

Answer 7

2nd electron affinity
The enthalpy change when 1 mole of
gaseous 2- ions is made from 1 mole of
gaseous 1- ions.

Question 8

(ΔHhyd)

Answer 8

Enthalpy change of hydration
The enthalpy change when 1 mole of
aqueous ions is formed from gaseous
ions.

Question 9

(ΔHsolution)

Answer 9

Enthalpy change of solution
The enthalpy change of solution refers to the amount of heat that is released or absorbed during the dissolving process (at constant pressure).

Question 10

(ΔHlattice) dissosciation

Answer 10

Lattice dissociation enthalpy
The enthalpy change when 1 mole of a
solid ionic compound is completely
dissociated into its gaseous ions.

Question 11

(ΔHlattice) formation

Answer 11

Lattice formation enthalpy
The enthalpy change when 1 mole of a
solid ionic compound is formed from its
gaseous ions

Question 12

Is enthalpy of formation ENDO OR EXO

Answer 12

EXO

Question 13

BOND DISSOSCIATION ENERGY - endo or exo

Answer 13

Endo

Question 14

Atomization ENDO OR EXO

Answer 14

ENDO

Question 15

Ionisation energy 1 and 2 endo or exo

Answer 15

ENDO

Question 16

1st electron affinity ENDO OR EXO (EXPLAIN)

Answer 16

EXOTHERMIC- energy is released when adding an electron to an atom

Question 17

2nd electron affinity ENDO OR EXO (EXPLAIN)

Answer 17

ENDO it requires energy to add an electron to a negative ion because the negative charges repel

Question 18

Enthalpy of hydration ENDO OR EXO

Answer 18

EXO

Question 19

Enthalpy of solution ENDO OR EXO

Answer 19

EITHER

Question 20

ΔH latt disc endo or exo

Answer 20

endo

Question 21

ΔH latt form endo or exo

Answer 21

exo

Question 22

Define entropy

Answer 22

A measurement of disorder in a system

Question 23

How do you calculate entropy change

Answer 23

ΔS° = ΣS°(products) - ΣS°(reactants)

Question 24

What are the units of entropy

Answer 24

J K mol-1

Question 25

What are the units of enthalpy

Answer 25

kJ K mol-1

Question 26

How do you calculate Gibbs free energy

Answer 26

ΔG° = ΔH° - TΔS°

Question 27

What does it mean if a reaction is feasible

Answer 27

It will happen

Question 28

What does it mean if a reaction is spontaneous

Answer 28

A reaction will happen without ‘prompt’ (excluding Ea barrier)

Question 29

What does the value of G have to be for a reaction to be feasible

Answer 29

0 or below

Question 30

What are the units of Gibbs free energy

Answer 30

kJ mol-1