60 g of ice at 0 ° C is added to 200 g of water initially at 70 ° C in a calorimeter of unknown water equivalent W . If the final temperature of the mixture is 40 ° C , then the value of W is [Take latent heat of fusion of ice L f = 80 cal g - 1 and specific heat capacity of water s = 1 cal g - 1 ° C - 1 ]

Step-by-step solution

The principle of calorimetry states that for an isolated system, The heat gained by the cold body (Here it is ice) = The heat lost by the hot body (Here it is water + calorimeter) m ice L f + m ice s ∆ T = m water + W s ∆ T ⇒ 60 × 80 + 60 × 1 × 40 = 200 + W × 1 × 30 ⇒ 480 + 240 = 600 + 3 W ⇒ W = 40   g