Answer Happy

Thermal physics 2 a) In normal atmospheric conditions (a pressure of 101 kPa), 1 kg of ice at a temperature of -20°C is heated until it becomes steam at a temperature of 120°C. Note: the heat capacity of ice = 2.05 kJ kg-¹ K-¹, heat capacity of water = 4.18 kJ kg-¹ K-¹, heat capacity of steam = 2.08 kJ kg-¹ K-¹. Latent heat of fusion for water = 333.55 kJ kg-¹, latent heat of vaporisation for water = 2257 kJ kg-¹. i. (2 marks) Sketch a graph of 'heat added' against temperature, clearly labelling the phase changes of the process. (4 marks) ii. How much heat is required to achieve this change in temperature? b) A student is carrying out and experiment to measure the specific heat capacity of water. The experiment involves heating water in a kettle of known power, and measuring the time taken for the water to boil and the temperature of the water over time. What source of uncertainty should the student consider, and what could the student do to minimise uncertainty in this experiment? (2 marks)