C1 2017

Question 1

1a Define enthalpy of lattice formation

Answer 1

Enthalpy change at constant pressure when 1 mole of solid ionic compounds formed from its gaseous ions

Question 2

1d How to indicate iodide ions in aq solution and describe observation made

Answer 2

AgNO3
Yellow Ppt

Question 3

7b State why chloride ions in this compound are not considered to be ligands

Answer 3

Cl- not donating lone pair
Cl- does not form coordinate bond

Question 4

8b How a student could distinguish between aq sol of MgCl2 and AlCl3

Answer 4

NaOH
MgCl2 - White ppt
AlCl3 - White ppl dissolves in excess

Question 5

9c Deduce the optimum conditions for the industrial conversion of methane and steam into gaseous products (6 MARKER)

Answer 5

Yield increases as temp increases
After certain temp yield no longer increases
Yield decreases as pressure increases

High temp is expensive
Yield no longer increases so no point in going higher
Optimum is (800)

Low pressure is too slow
So compromise pressure required
Optimum pressure is (1000)

Question 6

11b Suggest why value of the enthalpy change for this reaction is close to zero

Answer 6

Same type and number bonds broken

Question 7

11c State type of isomerism shown by iron complex

Answer 7

Optical

Question 8

11d Suggest one reason why people who eat these foods do not suffer from poisoning

Answer 8

Low concentrations