Properties Of Solids And Liquids Question 70
Question: 1 g of a steam at 100°C melt how much ice at 0°C? (Latent heat of ice = 80 cal/gm and latent heat of steam = 540 cal/gm) [Pb. PET 2000]
Options:
A) 1 gm
B) 2 gm
C) 4 gm
D) 8 gm
Show Answer
Answer:
Correct Answer: D
Solution:
Suppose m gm ice melted, then heat required for its melting $ =mL=m\times 80cal $
Heat available with steam for being condensed and then brought to 0°C $ =1\times 540+1\times 1\times (100-0)=640cal $
therefore Heat lost = Heat taken therefore $ 640=m\times 80 $
therefore $ m=8gm $
Short trick: You can remember that amount of steam (m’) at 100°C required to melt m gm ice at 0°C is $ m’=\frac{m}{8} $ . Here, $ m=8\times m’=8\times 1=8gm $
