Final answer:
To calculate the grams of water that condense out of each cubic meter of air when the temperature drops, you need to find the difference in saturation density of water vapor between the two temperatures.
Step-by-step explanation:
The question is asking how many grams of water must condense out of each cubic meter of air if the temperature falls from 25.0°C to 15.0°C, given a relative humidity of 90.0%. To solve this, we need to calculate the difference in saturation density of water vapor between the two temperatures. The saturation density at 25°C can be found using a table or formula, and then the saturation density at 15°C can be calculated. The difference between the two densities will give us the amount of water that condenses.
Let's say the saturation density at 25°C is 10 g/m³ and the saturation density at 15°C is 8 g/m³. The difference is 10 g/m³ - 8 g/m³ = 2 g/m³. Therefore, 2 grams of water must condense out of each cubic meter of air when the temperature drops from 25.0°C to 15.0°C.