Question

Steam at ${100}^{o}C$ is passed into 1.1 kg of water contained in a calorimeter of water equivalent 0.02 kg at ${15}^{o}C$ till the temperature of the calorimeter and its contents rises to ${80}^{o}C.$ The mass of the steam condensed in kg is

• A. 0.130
• B. 0.065
• C. 0.260
• D. 0.135

Answer 1

Answer: (D)

. 0.135

Heat required $Q=ms△T$

where m = mass of the water, s = heat capacity of water and $△T$ = change in temperature.

$Q=(1.1+0.02)\times {10}^3\times 1\times (80-15)=72800cal.$

Therefore, mass of steam condensed (in kg)
$m=\frac{Q}{L}$ where 'L' is the latent heat of steam.

$m=\frac{72800}{540}\times {10}^{-3}=0.135kg.$