Thermal Energy Transfer (Edexcel International A Level Physics)

A kettle was used to heat 855 g of water to boiling point. The initial temperature of the water was 21.5 °C and it took 115 s to heat the water to 100 °C.

The kettle is left switched on for 175 s after the water has reached 100 °C.

Calculate the mass of water that was boiled away.

specific heat capacity of water = 4190 J kg⁻¹ K⁻¹
specific latent heat of vaporisation of water = 2.26 × 10⁶ J kg⁻¹

Mass of water that was boiled away = .........................................

In the book Charlie and the Chocolate Factory, a palace is made entirely from chocolate.

Soon after it was made the palace melted, due to energy transfer from the Sun.

The total volume of chocolate used for the palace was 1250 m³. The initial temperature of the chocolate palace was 28.5°C. Chocolate melts at a temperature of 36.0°C.

The book states that the palace melted completely in less than a day.

Deduce whether this statement could be correct.

rate of energy transfer to the palace = 7.5 × 10⁵ W
density of chocolate = 1325 kg m⁻³
specific latent heat of chocolate = 4.5 × 10⁴ J kg⁻¹
specific heat capacity of chocolate is 1.30 × 10³ J kg⁻¹ K⁻¹