A certain volume of air holds 20 grams of water vapor. At that temperature, the maximum amount the air can contain is 100 grams. What is the relative humidity?

Relative humidity is the ratio of mass of water vapor to the maximum mass of water vapor required to saturate the air at a given temperature. It is expressed in percentage and depends on temperature and the pressure of the system of interest.

The relative humidity  from the given question is 20%

Explanation:

Relative humidity is the ratio of mass of water vapor to the maximum mass of water vapor required to saturate the air at a given temperature. Relative humidity depends on temperature and the pressure of the system of interest.

Relative humidity is given as;

(Mass of water vapor present / maximum mass of water vapor required to saturate the air) * 100%

Given;

mass of water vapor = 20 grams

maximum mass of water vapor required to saturate the air = 100 grams

Relative humidity = (20/100) * 100

Relative humidity = 20%

the correct answer would be b) volume versus temperature, because they are also directly proportional.