Page 19 - 1202 Question Bank Chemistry Form 4 KSSM

PAPER 3

You are required to compare the electrical conductivity of molten X and molten Y.
Prepare the apparatus set-up as in Diagram 1 and carry out the experiment according to the given procedure.

Procedure:
1. Fill a crucible with solid X until it is half full.
2. Place carbon electrodes into the solid X.
3. Complete the circuit by connecting carbon electrodes to Batteries
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switch, bulb and batteries.
4. Turn on the switch and observe whether the bulb is lighted up. Bulb Switch
Turn off the switch. Carbon
5. Then, heat the solid X until it is melted. Turn on the switch Crucible electrodes
again and observe whether the bulb is lighted up. Solid X
6. Steps 1 to 5 are repeated using solid Y.
Based on the experiments carried out, answer the following. Heat
(a) Complete the Table 1. [6 marks]
Diagram 1
Table 1
Compound Physical state Observation Inference
Solid
X
Molten
Solid
Y
Molten

(b) For this experiment, state the [3 marks]
(i) manipulated variable
(ii) responding variable
(iii) constant variable
(c) State one hypothesis for this experiment. [2 marks]
(d) State the operational definition of electrical conductivity this experiment. [2 marks]
(e) Explain why molten sulphur cannot conduct electricity. [2 marks]

Note:
If you are not able to carry out the experiment as described above, you can answer this question using the following
samples of data:

Compound Physical state Observation Inference
Solid Bulb does not light up Compound X conducts electricity in molten
X
Molten Bulb is lighted up state but not in solid state.
Solid Bulb does not light up Compound Y cannot conduct electricity in solid
Y and molten states.
Molten Bulb does not light up

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