Question

A volume of 150 m3 of room air contains 1800 g at 22 ° C water vapor. What is the relative humidity of room air? Pressure 101.3 kPa.

Answer 1

Solution:

Relative humidity is the ratio of vapor density to saturation vapor density:

$$\phi=\frac{\rho} {\rho_0} 100\%$$

Vapor density is equal to mass of vapor divided by the volume of the room:

$$\rho=\frac{m} {V}$$

Therefore:

$$\phi=\frac{m} {V\rho_0} 100\%$$

Saturation vapor density at $22^\circ\:C:$

$$\rho_0=19.4\:g/m^3$$

Now we can calculate relative humidity:

$$\phi=\frac{1800} {150\times19.4} 100\%=62\%$$

Answer:

$$\phi=62\%$$