Steam at 100oc is passed into 1.1 g of water contained in a calorimeter of water equivalent 0.02 g at 15oC till the temperature of the calorimeter and its contents rises to 80oC. The mass of the steam condensed in g is

Heat is lost by steam in two stages: (i) for change of state from steam at 100oC to water at 100oC is m x 540(ii) to change water at 100oC to water at 80oC is m × 1 × (100 - 80), where m is the mass of steam condensed.Total heat lost by steam is m × 540 + m × 20 = 560m (cals) Heatgained by calorimeter and its contents is=(1.1+0.02)×(80−15)=1.12×65 cals using Principle of calorimetery, Heat gained = heat lost∴560m=1.12×65 ⇒m=0.130gm