What is the partial pressure of water on a day when the temperature is 25C and the relative humidity is 33%
P=___Pa
To calculate the partial pressure of water, we first need to determine the vapor pressure of water at 25°C. The vapor pressure of water varies with temperature. One commonly used formula to estimate the vapor pressure of water is the Antoine equation:
log10(P) = A - (B / (T + C))
Where:
P is the vapor pressure of water in mmHg (millimeters of mercury),
T is the temperature in Celsius,
A, B, and C are constants.
For water, the constants are typically:
A = 8.07131
B = 1730.63
C = 233.426
Let's calculate the vapor pressure of water at 25°C:
T = 25°C
log10(P) = 8.07131 - (1730.63 / (25 + 233.426))
Now, we need to convert the result from millimeters of mercury (mmHg) to Pascals (Pa). The conversion factor is:
1 mmHg = 133.322 Pa
Let's proceed with the calculations:
P (mmHg) = 8.07131 - (1730.63 / (25 + 233.426))
P (Pa) = P (mmHg) * 133.322
Now that we have the vapor pressure of water, we can calculate the partial pressure of water using the relative humidity (RH) as follows:
partial pressure of water = relative humidity * vapor pressure of water
RH = 33% (convert to decimal: 0.33)
partial pressure of water = 0.33 * vapor pressure of water
Let's calculate the partial pressure of water:
partial pressure of water = 0.33 * vapor pressure of water
Now you can substitute the values and solve for the partial pressure of water.