Final answer:
The question involves calculating the amount of water that must condense from the air as temperature drops and affects relative humidity, requiring knowledge of the saturation point of water at different temperatures.
Step-by-step explanation:
The question concerns the condensation of water from the air as the temperature drops and how this relates to the concept of relative humidity. The relative humidity is the amount of moisture in the air compared to what the air can hold at that temperature. When temperature drops, the capacity of the air to hold water vapor decreases and water may condense out.
Let's calculate the amount of water that would condense out given the change in temperature:
- Determine the mass of water vapor present at 25.0°C when the relative humidity is 90.0%.
- Calculate the maximum capacity of air to hold water vapor at the lower temperature of 15.0°C.
- The difference between these two values would be the mass of water that needs to condense to maintain equilibrium at the new temperature.
This calculation would use psychrometric equations or tables to establish the actual grams of water per cubic meter at both temperatures. Unfortunately, specific values for the saturation point of water at different temperatures are needed for these calculations, and those are not provided in the question, so we cannot calculate the exact amount of water that would need to condense.