Figure 5 shows the apparatus used to investigate the melting of some crushed ice - Edexcel - GCSE Physics - Question 3 - 2023 - Paper 2

One effective method for heating the crushed ice is to use a Bunsen burner to provide heat.

Initially, from P to Q, the temperature of the crushed ice increases, reaching 0°C.

From Q to R, the temperature remains constant at 0°C as the ice and water mixture begins to melt.

Finally, from R to S, the temperature of the water increases as the melted ice transitions to liquid, indicating that the melting process is complete and the contents are now all liquid.

We will use the equation:

$V₂ = \frac{P₁ \times V₁}{P₂}$

Plugging in the values:

$V₂ = \frac{3.30 \text{ atm} \times 0.50 \text{ L}}{1.07 \text{ atm}}$

Calculating gives:

$V₂ ≈ \frac{1.65}{1.07} ≈ 1.54 \text{ L}$

Thus, the volume of the bubble near the surface is approximately 1.54 litres.