The device shows the relative humidity at 22°
c. what’s the water vapor density if the maximum water vapor in air at this temperature is 20 grams/cubic meter? a device showing that at 22 degrees celsius the relative humidity is 58%.
a. 11.6%
b. 11.6 g/m3
c. 12.76%
d. 12.76 g/m3

The relative humidity shows us saturation of water in air. Since it is 58% and not 100% we have to scale density that we were given when humidity is 100%.

At 100% humidity, density is 20grams/cubic meter

at 58% it will be:
0.58 * 20 = 11.6 g/m^3

Since the question is to find density, the answer cannot be in %.

Answer is 11.6 g/m^3