AQA · GCSE · Combined Science · Higher

Measuring specific heat capacity

Q02.1 6 marks

A student made measurements to determine the specific heat capacity of vegetable oil. Figure 2 shows the equipment used.

Diagram of apparatus for determining the specific heat capacity of vegetable oil. The equipment is labelled joulemeter, electric heater, beaker, top pan balance and thermometer. — Figure 2

Describe how the student could use the equipment shown in Figure 2 to determine the specific heat capacity of vegetable oil.

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Marking points

1 Measure the mass of the vegetable oil using the top pan balance.
2 Measure the starting temperature of the oil with the thermometer.
3 Put the beaker of oil on the electric heater and switch the heater on.
4 Use the joulemeter to measure the energy transferred to the oil.
5 Measure the final temperature of the oil with the thermometer.
6 Calculate the temperature rise, $\Delta\theta$ , from the final and starting temperatures.
7 Use $E=mc\Delta\theta$ and rearrange to calculate the specific heat capacity, $c$ .
8 Present the steps in a logical sequence that would produce a valid result.

Full-mark answer

Measure the mass of the vegetable oil using the top pan balance. Measure the starting temperature of the oil with the thermometer. Put the beaker of oil on the electric heater and switch on the heater. Use the joulemeter to measure the energy transferred to the oil. Measure the final temperature of the oil, then calculate the temperature rise, $\Delta\theta$ . Use $E=mc\Delta\theta$ and rearrange it to calculate $c$ .

Why this answer loses marks

Heat the oil and measure its temperature.

This includes only a very limited method. It omits mass, energy transferred, temperature rise and use of the specific heat capacity equation.

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