How much water vapor does 1 m3 of air contain at a temperature of + 10C if its relative humidity is: a) 100% B) 50% c) 10%?

To begin with, let’s define the concept of relative humidity. Relative humidity is the ratio of the partial pressure of water vapor to the pressure of saturated water vapor at the same temperature.
The pressure of saturated water vapor at 10 degrees is 9.21 mm Hg. Art., for calculations we translate into Pascals: 9.21 x 133.3 = 1227.7 Pa.
Atmospheric pressure is 101 kPa – 101,000 Pa.
Now let’s calculate the partial pressure of water vapor in air at
a) 100% – 1227.7 Pa, and atmospheric – 101000 Pa.
The sum of the partial pressures of air and water is equal to atmospheric pressure. The pressure is proportional to the concentration, which means that the concentration of water molecules is: (1227.7 / 101000) x 100% = 1.215%
b) 50% is (1227.7 x 0.5) = 614 Pa
concentration (614/101000) x 100% = 0.608%
d) 10% is (1227.7 x 0.1) = 122.77 Pa
concentration (122.77 / 101000) x 100% = 0.121%