Ptotal = pH2 + pH2O
Ptotal is what you read as the room pressure. pH2O is the vapor pressure of H2O which you can obtain from tables in your book at the corresponding temperature.
Ptotal is what you read as the room pressure. pH2O is the vapor pressure of H2O which you can obtain from tables in your book at the corresponding temperature.
To obtain the partial pressure of hydrogen gas, you will need to use Dalton's Law of partial pressures. According to this law, the total pressure of a mixture of non-reacting gases is equal to the sum of the partial pressures of each individual gas.
In this case, the total pressure of the wet gas is obtained by collecting it over water. When gases are collected over water, the water vapor also contributes to the total pressure. Since the gas is said to be "wet," it means that water vapor is present in addition to the gas produced by the reaction.
To determine the partial pressure of hydrogen gas, you will need to subtract the vapor pressure of water from the total pressure of the wet gas. The vapor pressure of water depends on the temperature and can be obtained from reference tables or online sources.
By subtracting the vapor pressure of water from the total pressure, you can obtain the partial pressure of hydrogen gas.
To summarize:
1. Collect the gas evolved from the reaction of the metal sample with acid over water.
2. Measure the total pressure of the wet gas.
3. Obtain the vapor pressure of water at the given temperature from reference tables or online sources.
4. Subtract the vapor pressure of water from the total pressure to obtain the partial pressure of hydrogen gas.
Remember, the necessary data such as vapor pressure of water can be found in reference tables or online sources.