A liquid at 30°C is poured very slowly into a Calorimeter that is at temperature of 110°C. The boiling temperature of the liquid is 80°C. It is found that the first 5 gm of the liquid completely evaporates. After pouring another 80 gm of the liquid the equilibrium temperature is found to be 50°C. The ratio of the Latent heat of the liquid to its specific heat will be ____ C.
[Neglect the heat exchange with surrounding]
[Neglect the heat exchange with surrounding]
Answer: 270
Solution
Let:
First 5 g evaporates:
Heat lost by calorimeter = Heat gained by liquid (to reach 80°C) + Heat for evaporation
... (i)
After adding 80 g more:
Calorimeter is now at 80°C, equilibrium at 50°C.
... (ii)
From (i) and (ii):
- m = mass of calorimeter
- x = specific heat of calorimeter
- s = specific heat of liquid
- L = latent heat of liquid
First 5 g evaporates:
Heat lost by calorimeter = Heat gained by liquid (to reach 80°C) + Heat for evaporation
... (i)
After adding 80 g more:
Calorimeter is now at 80°C, equilibrium at 50°C.
... (ii)
From (i) and (ii):
JEE Advanced · 2019 · 27 May 2019 · Paper 1 · Numerical answer