In an air-water vapor mixture at 30°C, the partial pressure of the water vapor is 1.7 kPa, and the partial pressure of the dry air is 100.5 kPa. The saturation pressure for water vapor at 30°C is 4.00 kPa.

What is the relative humidity of the air-water vapor mixture in percent?

a) 32.5%
b) 42.5%
c) 52.5%
d) 62.5%

Correct option is B) The relative humidity of the air-water vapor mixture at 30°C, with a partial pressure of water vapor at 1.7 kPa against a saturation pressure of 4.00 kPa, is calculated to be 42.5%.

Explanation:

The student has asked how to calculate the relative humidity of an air-water vapor mixture at a certain temperature. Relative humidity is defined as the ratio of the partial pressure of water vapor in the air to the saturation pressure of water vapor at that temperature, expressed as a percentage. With a partial pressure of water vapor at 1.7 kPa and a saturation pressure at 30°C being 4.00 kPa, the relative humidity can be found by dividing the former by the latter and then multiplying by 100 to get a percentage.

The relative humidity (RH) can be calculated using the formula: RH = (Partial pressure of water vapor / Saturation pressure of water vapor) x 100%

So, the relative humidity is: RH = (1.7 kPa / 4.00 kPa) x 100% = 42.5%

Therefore, the answer is b) 42.5%, which is the relative humidity of the air-water vapor mixture at 30°C.