Question 18M.2.hl.TZ1.6
| Date | May 2018 | Marks available | [Maximum mark: 8] | Reference code | 18M.2.hl.TZ1.6 |
| Level | hl | Paper | 2 | Time zone | TZ1 |
| Command term | Annotate, Calculate, Deduce, Determine, Identify | Question number | 6 | Adapted from | N/A |
The diagram shows an incomplete voltaic cell with a light bulb in the circuit.
Identify the missing component of the cell and its function.
[2]
salt bridge
movement of ions
OR
balance charge
Do not accept “to complete circuit” unless ion movement is mentioned for M2.
[2 marks]
Deduce the half-equations for the reaction at each electrode when current flows.
[2]
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]
Annotate the diagram with the location and direction of electron movement when current flows.
[1]
in external wire from left to right
[1 mark]
Calculate the cell potential, in V, using section 24 of the data booklet.
[1]
«E = +0.80 V – (–2.37 V) = +» 3.17 «V»
[1 mark]
Determine the loss in mass of one electrode if the mass of the other electrode increases by 0.10 g.
[2]
«moles of silver »
moles of magnesium
«loss in mass of magnesium » 0.011 «g»
Award [2] for correct final answer.
[2 marks]
