Question

The latent heat of vaporisation of water is (a) 2.25 Ã 106 J/kg
(b) 3.34 Ã 106 J/kg
(c) 22.5 Ã 104 J/kg
(d) 33.4 Ã 105 J/kg

Answer 1

2,260 kJ/kg

Explanation:

We are asked to find the latent heat of vapourization of water.

• The latent of vapourization is a property of a substance by which it tells us the amount of heat required for the substance to change its state from liquid to gas.

• For water the latent heat of vapourization is required at 100°C.

• The the change of state happens from liquid to gas.In the case of water ,boiling water get converted into steam.

• The value of latent heat of vapourization is dependent on the properties of water.The experimental value found out for water is 2,260 kJ/kg.

Answer 2

Answer is Option (a)

Explanation:

• The Quantity that is required to convert 1 kg (Kilogram) of the water ($H_2O$) from Liquid to vapour or gaseous state, but there should not be change in temperature, is called Latent Heat of Vaporization.

In case of Water the Latent heat of vaporization comes out to be $22.5 \times 10^5$ joules per kilogram or $22.5 \times 10^5 Jkg^-^1$

So, we can judge that $22.5 \times 10^5$ J is needed as Heat for changing 1 Kg of water (keeping Boiling water at 100°C) into steam at 100°C, the same temperature.