# Heat Of Vaporization Formula

What is Heat of Vaporization?

The Heat of Vaporization is the quantity of heat that needs to be absorbed to vaporize a particular quantity of liquid at a constant temperature. If the solutions of vapour and liquid states are compared, the kinetic energy of the steam is proved to be higher than the kinetic energy of the fluid.

In other words, the heat of vaporization is the total amount of heat required to turn a particular quantity of liquid into vapour without any rise in the temperature of the fluid.

Heat of Vaporization Formula
Based on entropy and enthalpy of vaporization and relationship among them, the Heat of vaporization formula can be written as

Hv = q / m

Wherein,

Hv = vaporization heat

m = mass of the substance

q = heat

Example1

If the heat of vaporization for H20 is 2357 J/g, calculate the total amount of heat energy that required to vaporize 145 grams of H20.

Solution:

The heat of vaporization formula

$H_{v}=\frac{q}{m}$

q = Hv x m

q= 2357 x 145

Therefore q = 341765 J