A student carries out an experiment using a polystyrene cup that contains 0.35 kg0.35\text{ kg}0.35 kg of water at 22∘C22^\circ\text{C}22∘C. The thermal capacity (heat capacity) of the cup is negligible.
Define thermal capacity.
Several ice cubes are at a temperature of 0∘C0^\circ\text{C}0∘C. The ice cubes are dropped into the water and the internal energy of the water decreases.
Give a simple molecular account of this decrease in internal energy.
The specific heat capacity of water is 4200 J/(kg⋅∘C)4200\text{ J}/(\text{kg}\cdot^\circ\text{C})4200 J/(kg⋅∘C).
Calculate the decrease in the internal energy of the water as its temperature decreases from 22∘C22^\circ\text{C}22∘C to 0∘C0^\circ\text{C}0∘C.
decrease in internal energy=........................... \text{decrease in internal energy} = \text{...........................} decrease in internal energy=...........................As the temperature of the water decreases, some of the ice melts.
Explain why this ice melts.
Describe how to determine the specific latent heat of fusion of ice using this experiment. State any other measurements that the student needs to make.
528 exam-style questions on CIE IGCSE Physics 2.2 Thermal properties and temperature, covering 2.2.1 Thermal expansion of solids, liquids and gases, 2.2.2a Internal energy and temperature, 2.2.2b Specific heat capacity, 2.2.3a Melting, boiling, condensation and solidification, 2.2.3b Evaporation, and 2.2.3c Cooling by evaporation. Each one has a worked solution and a mark scheme showing where the marks go.