If 20dm³ of hydrogen where collected over water at 17°C and 797knm² pressure
A. Calculate the pressure of a drying hydrogen gas at this temperature
Ptotal = pH2(dry) + pH2O
You know Ptotal
You can look up pH2O in vapor pressure tables @ 17 C
Substitute and solve for pdryH2.
To calculate the pressure of dry hydrogen gas at a given temperature, we need to apply Dalton's Law of Partial Pressures. This law states that the total pressure of a mixture of gases is equal to the sum of the partial pressures of each gas.
In this case, the total pressure is given as 797 kNm², and the gas is collected over water. To determine the partial pressure of the dry hydrogen gas, we need to account for the vapor pressure of water at the given temperature.
1. Look up the vapor pressure of water at 17°C, which is approximately 2.34 kPa.
2. Convert the pressure from kNm² to kPa. 1 kNm² is equal to 100 kPa. Therefore, the given pressure of 797 kNm² is equal to 79700 kPa.
3. Subtract the vapor pressure of water from the total pressure to get the partial pressure of the dry hydrogen gas.
Partial Pressure of Dry Hydrogen = Total Pressure - Vapor Pressure of Water
Partial Pressure of Dry Hydrogen = 79700 kPa - 2.34 kPa
Performing the subtraction:
Partial Pressure of Dry Hydrogen = 79700 - 2.34 = 79697.66 kPa
So, the pressure of the dry hydrogen gas at this temperature is approximately 79697.66 kPa.