Question

Steam at 100∘C is passed into 1.1 kg of water contained in calorimeter of water equivalent 0.02 kg at 15∘C till the temperature of the calorimeter rises to 800C. What is the mass of steam condensed?

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

Answer 1

Answer: (A)

(A) 0.130

Answer 2

Explanation:
The amount of heat lost by the steam to condense into the water at 100°C and in raising the temperature of water and calorimeter to 80°C is H1=mL+mcΔTwherem: Mass of steamL=540cal/g Latent heat of vaporization of steamΔT=100∘C−80∘C=20∘C Decrease in temperaturec=1 cal /g∘C Specific heat of waterNow, the amount of heat gained by water to increase its temperature from 15∘C to 80∘C isH2=1.1kg×c×(80−15)∘C⇒H2=1.1×103g×1cal/g∘C×65∘C⇒H2=71500calAgain, the amount of heat gained by the calorimeter to increase its temperature from 15∘C to 80∘C isH3=0.02kg×c×(80−15)∘C⇒H3=0.02×103g×1cal/g∘C×65∘C⇒H3=1300calFrom the principle of calorimetry, we haveH1=H2+H3⇒mL+(mc×20∘C)=71500cal+1300cal⇒540cal/g×m+(m×1cal/g∘C×20∘C)=72800cal⇒560 cal /g×m=72800cal⇒m=72800560g=130g⇒m=0.130kgTherefore, the mass of steam condensed is 0.130kg.Hence, the correct option is (A).