how do i find how much water vapor is in the air when given relative humidity and an air sample that is 40 degrees C?
the relative humidity is 30%
To find the amount of water vapor in the air when given the relative humidity and air sample temperature, you need to use the concept of saturation vapor pressure. Saturation vapor pressure is the maximum amount of water vapor that can exist in the air at a given temperature.
Here's how you can calculate it:
1. Convert the air sample temperature from Celsius (°C) to Kelvin (K) by adding 273.15. In this case, the temperature is 40°C, so it becomes 40 + 273.15 = 313.15 K.
2. Use a reference table or look up online for the saturation vapor pressure at the given temperature. Let's assume that the saturation vapor pressure at 313.15 K is 2.3 kPa (kilopascals).
3. Calculate the actual vapor pressure, which represents the amount of water vapor in the air. To do this, multiply the saturation vapor pressure (2.3 kPa) by the relative humidity (expressed as a decimal). If the relative humidity is given as a percentage, divide it by 100 to convert it to decimal form. For example, if the relative humidity is 80%, divide it by 100 to get 0.8.
Actual vapor pressure = saturation vapor pressure × relative humidity
Actual vapor pressure = 2.3 kPa × 0.8 = 1.84 kPa
So, based on the given relative humidity and air sample temperature of 40°C, the amount of water vapor in the air is approximately 1.84 kilopascals (kPa).