Question

A copper calorimeter contains 50 g of water at 16°C. When 40 g of water at 36°C is added, the resulting temperature of the mixture is 24°C. Calculate the heat capacity of the calorimeter.

Answer 1

Let the heat capacity of the copper calorimeter be C' J °C⁻¹.

Heat lost by hot water:

Q_lost = 40 × 4.2 × (36 − 24)

= 2016 J

Heat gained by cold water:

$$Q_{\text{gained by water}} = 50 \times 4.2 \times (24 - 16)$$

= 1680 J

Heat gained by the calorimeter:

$$Q_{\text{gained by calorimeter}} = C' \times (24 - 16)$$

= 8C'

From the principle of calorimetry:

1680 + 8C' = 2016

8C' = 336

C' = 42 J °C⁻¹

Therefore, the calorimeter's heat capacity is 42 J °C⁻¹.