In 4 cubic meters of air at a temperature of 16 C there is 40 g of water vapor. Find the relative humidity.

Answer: 73.5%.
Explanation: to solve this problem, you must use the formula:
f = p / p (n.p.), where f is the relative humidity of the air, p is the density of water vapor actually in the air, p (n.p.) is the density of saturated vapor at a given temperature. According to the reference table, we determine that at 16 C p (n.p.) = 13.6 g / m ^ 3.
In addition: p = m / v, where m is the mass of the vapor, v is the volume of the vapor, and p is the density.
Now we substitute the known data into the formula and get:
f = m / v * p (n.p.) = 40 / (4 * 13.6) = 0.735