**q1 ****Answers**

**Questions**

5) Figure 6 shows a kettle a student used to determine the specific heat capacity of water. F

The student placed different masses of water into the kettle and timed how long it took for the water to reach boiling point.

The student carried out the experiment three times.

The student’s results are shown in

The student carried out the experiment three times.

The student’s results are shown in

**Table 2**.5.1) Suggest how the student was able to ensure that the change in temperature was the same for each mass of water. [2 marks]

5.2) Calculate the uncertainty in the student’s measurements of time to boil when the mass of water was 1.75 kg. [2 marks]

5.2) Calculate the uncertainty in the student’s measurements of time to boil when the mass of water was 1.75 kg. [2 marks]

Uncertainty = _____________ s

5.3) The power rating of the kettle is 2.20 kW. Calculate the average electrical energy used by the kettle, in kJ, for 1.75 kg of water to reach boiling point. [2 marks]

Average energy = ____________ kJ

5.4) Use information from Table 2 to calculate the change in temperature of the water during the investigation. [2 marks]

Change in temperature = ____________ °C

The student plotted a graph of energy supplied in kJ against mass × change in temperature in kg °C.

**Figure 7**shows the graph the student plotted.5.5) Use data from

5.6) Use the graph to determine the mean value of the specific heat capacity of water, for the student’s investigation. [4 marks]

**Table 2**to plot the four missing points. Draw a line of best fit on the graph. [3 marks]5.6) Use the graph to determine the mean value of the specific heat capacity of water, for the student’s investigation. [4 marks]

Specific heat capacity of water = __________ J/kg °C

5.7) The student’s value for the specific heat capacity of water was greater than the accepted value.

Suggest why. [1 mark]

5.8) The kettle used in the experiment had a label stating that the power rating of the kettle was 2.2 kW.

The student did not measure the power of the kettle.

Suggest why measuring the power of the kettle may improve the student’s investigation. [1 mark]

Suggest why. [1 mark]

5.8) The kettle used in the experiment had a label stating that the power rating of the kettle was 2.2 kW.

The student did not measure the power of the kettle.

Suggest why measuring the power of the kettle may improve the student’s investigation. [1 mark]

**(Total for Question 5 = 17 marks)**