Q: A piece of ice (heat capacity = 2100 J/Kg °C and latent heat = 3.36 × 105 J/Kg) of mass m grams is at -5°C at atmospheric pressure. It is given 420 J of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that 1 gm of ice has melted. Assuming there is no other heat exchange in the process. Find the value of m.
Sol: Here, heat given is used to increase the temperature of the ice to 0°C and to melt 1 gm of ice.
Given m is mass of ice in gm.
420 = (m × 2100 × 5 + 1 × 3.36 × 105) × 10-3
⇒ m = 8 gm.