DP Chemistry (last assessment 2024)
Question 18M.2.sl.TZ1.6
| Date | May 2018 | Marks available | [Maximum mark: 5] | Reference code | 18M.2.sl.TZ1.6 |
| Level | sl | Paper | 2 | Time zone | TZ1 |
| Command term | Annotate, Deduce, Identify | Question number | 6 | Adapted from | N/A |
6.
[Maximum mark: 5]
18M.2.sl.TZ1.6
The diagram shows an incomplete voltaic cell with a light bulb in the circuit.
(a)
Identify the missing component of the cell and its function.
[2]
Markscheme
salt bridge
movement of ions
OR
balance charge
Do not accept “to complete circuit” unless ion movement is mentioned for M2.
[2 marks]
(b)
Deduce the half-equations for the reaction at each electrode when current flows.
[2]
Markscheme
Positive electrode (cathode):
Ag+(aq) + e– → Ag(s)
Negative electrode (anode):
Mg(s) → Mg2+(aq) + 2e–
Award [1 max] if correct equations given at wrong electrodes.
[2 marks]
(c)
Annotate the diagram with the location and direction of electron movement when current flows.
[1]
Markscheme
in external wire from left to right
[1 mark]