A student determined the specific latent heat of vaporisation of water - AQA - GCSE Physics - Question 5 - 2022 - Paper 1

The power output of the heater is classified as a control variable, as it remained constant throughout the experiment.

One way to safely move the beaker of boiling water is to use tongs or gloves to avoid direct contact with the hot beaker.

To calculate the specific latent heat of vaporisation (L), we can use the formula:

$L = \frac{Q}{m}$

Where:

• Q = total energy transferred = 25 200 J
• m = mass of water that turned into steam = 0.0090 kg

Now substituting the values:

$L = \frac{25\,200 \, \text{J}}{0.0090 \text{ kg}} = 2,800,000 \text{ J/kg}$

Thus, the specific latent heat of vaporisation is 2.8 x 10^6 J/kg.

A potential source of error in the student's experiment could be the transfer of thermal energy from the water to the surroundings, which may affect the accuracy of the measurements.