Question

2 kg of ice melts when water at 100℃ is poured in a hole drilled in a block of ice. What mass of water was used? Given: specific heat capacity of water = 4200 J kg^-1 K^-1, specific latent heat of ice = 336 × 10³ J kg^-1.

Answer 1

Since the whole block does not melt and only 2 kg of it melts, so the final temperature would be 0 °C.

Amount of heat energy gained by 2 kg of ice at 0°C to convert into water at 0°C = 2 × 336000 = 672000 J

Let amount of water poured = m kg.

Initial temperature of water = 100°C.

Final temperature of water = 0°C.

Amount of heat energy lost by m kg of water at 100°C to reach temperature 0°C = m × 4200 × 100

= 420000 m J

We know that heat energy gained = heat energy lost.

672000J = m × 420000 J

m = `672000/420000`

m = 1.6 kg