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A student investigated how the temperature of a lump of ice varied as the ice was heated - AQA - GCSE Physics - Question 11 - 2021 - Paper 1
Question 11
A student investigated how the temperature of a lump of ice varied as the ice was heated. The student recorded the temperature until the ice melted and then the wat... show full transcript
Worked Solution & Example Answer:A student investigated how the temperature of a lump of ice varied as the ice was heated - AQA - GCSE Physics - Question 11 - 2021 - Paper 1
Step 1
The specific heat capacity of ice is less than the specific heat capacity of water.
Answer
Figure 17 shows that while the temperature of ice increases slowly to 0 °C, the gradient of the temperature change is steeper for water. This indicates that ice requires less energy to change its temperature compared to water, confirming that the specific heat capacity of ice is less than that of water.
Step 2
The specific latent heat of fusion of ice is less than the specific latent heat of vapourisation of water.
Answer
In Figure 17, we see that there is a flat section where the temperature remains constant while ice melts. This indicates that the energy input during this phase change (fusion) is low compared to the energy required for the water to boil later. This demonstrates that the latent heat of fusion is less than that of vapourisation.
Step 3
Describe two ways the results of the experiment in Figure 17 would have been different.
Answer
- The graph would show a steeper gradient for the heating of water, indicating a faster increase in temperature due to the additional thermal energy loss to the surroundings.
- The plateaus where phase change occurs (melting and boiling) would be longer, as the excessive thermal energy would cause these processes to take more time, affecting the overall time recorded.
Step 4
Calculate the specific latent heat of vapourisation of water.
Answer
To calculate the specific latent heat of vapourisation (L), we use the formula:
where:
- E is the energy transferred (69,000 Joules),
- m is the mass of the water (0.030 kg).
Substituting the values gives:
Thus, the specific latent heat of vapourisation is 2,300,000 J/kg.