A cooling unit is used to condense a substance. The sample is initially entirely gas at its boiling point and has a mass of 0.30 kg. The specific latent heat of vaporisation of the substance is 1.5 × 106 J/kg. During the first two intervals, the sample remains at its boiling point while some of the gas condenses.
| Interval | Energy removed |
|---|---|
| 1 | 2.4 × 105 J |
| 2 | 1.2 × 105 J |
The cooling unit then transfers a further 7.5 × 104 J from the sample.
Calculate the mass of gas remaining after the first two intervals.
Explain, using a calculation, whether all of the sample will be liquid after the further energy transfer.
110 exam-style questions on Edexcel GCSE Physics 14.2 Specific heat capacity and latent heat, covering 14.2.1 Heating, temperature and changes of state, 14.2.2 Specific heat capacity and specific latent heat, 14.2.3 Specific heat capacity calculation, 14.2.4 Specific latent heat calculation, and 14.2.5 Reducing energy transfer through thermal insulation. Each one has a worked solution and a mark scheme showing where the marks go.