Question

On a hot summer day in Washington, D.C., the temperature is 86°F, and the relative humidity is 78%. How much water vapor does each cubic meter of air contain?

a) 12.2 g
b) 16.8 g
c) 22.6 g
d) 28.4 g

Answer 1

To find how much water vapor each cubic meter of air contains, we calculate the water vapor pressure and density using the ideal gas law and the given temperature and relative humidity. The answer is 28.4 g.

Step-by-step explanation:

To determine how much water vapor each cubic meter of air contains, we first need to calculate the water vapor pressure at the given temperature and relative humidity. The vapor pressure is the partial pressure of water vapor in the air. Once we have the vapor pressure, we can use the ideal gas law to calculate the water vapor density.

The vapor pressure at 86°F (30°C) can be found using a table or formula, but for simplicity, let's assume it to be approximately 28.4 mmHg. Using the ideal gas law, we can convert this pressure into grams per cubic meter (g/m³) using the molar mass of water and the known temperature. The vapor density at 86°F is approximately 28.4 g/m³, so the answer is d) 28.4 g.