Question

Suppose the latent heat of vaporization of water is 540 cal/g. how much heat (in calories) must be added to 50 grams of water at an initial temperature of 20 C ( C represent degree Celsius) to a. heat it to the boiling point?

b. then completely convert the water to steam?

Answer 1

First we will Heat given to 50g of water to reach to 100 ^oC.

Here,

m= 50g

S for water = 1 cal/gram ^oC

Second We have to find required to convert water into steam

L_v is latent heat of vapourization =540 cal/g

So, 31000 cal of energy is required to finally convert 50g of water into steam.