Enthalpy Change & Cycles

Question 1

Define enthalpy change of lattice formation (∆HLF)

Answer 1

Heat energy change when 1 mol solid ionic compound formed from it’s (g) ions

Question 2

Outline the meaning of exothermic and endothermic reactions

Answer 2

Exothermic = heat energy released/bonds made
Endothermic = heat energy taken in/bonds broken

Question 3

Define ∆H formation (∆HF)

Answer 3

Heat energy change of compound formed from it’s elements

Question 4

Define ∆H of atomisation (∆Hat)

Answer 4

Heat energy change when 1 mol (g) atoms formed from it’s elements in the standard state

Question 5

Define the ∆H of 1st ionisation energy (∆HIE)

Answer 5

Heat energy change when 1 mol of e- lost from 1 mol of (g) atoms

Question 6

Define the ∆H of 2nd ionisation energy (∆HIE2)

Answer 6

Heat energy change when 1 mol of e- taken from 1 mol of (g)

Question 7

Define the ∆H of 1st e- affinity (∆HEA)

Answer 7

Heat energy change when 1 mol of e- is added to 1 mol (g) atoms

Question 8

Define the ∆H of the 2nd e- affinity (∆HEA2)

Answer 8

Heat energy change when 1 mol of e- added to 1 mol (g) ions

Question 9

Outline the standard enthalpy change of formation equation (ΔH°f)

Answer 9

1. Write out equation at top with constituent elements below
2. Input the arrows into diagram (ensure the head is the right way round)
3. Input values and calculate ΔH°f

Question 10

Outline the difference between the arrow directions for the equations of (ΔH°f) and (ΔH°c)

Answer 10

(ΔH°f) = bottom to top
(ΔH°c) = top to bottom