Answer :
To find the partial pressure of hydrogen gas when it is collected over water, we need to use the concept of partial pressures.
When a gas is collected over water, the total pressure inside the collecting bottle is a combination of the pressure of the gas itself and the vapor pressure of the water. This is expressed by Dalton's Law of Partial Pressures, which states that the total pressure is the sum of the partial pressures of each gas present.
Here's how we can solve this problem step-by-step:
1. Identify the Total Pressure:
- The total pressure in the collecting bottle is given as 97.1 kilopascals (kPa).
2. Identify the Vapor Pressure of Water:
- The vapor pressure of the water is given as 3.2 kilopascals (kPa).
3. Apply Dalton's Law:
- According to Dalton's Law, the total pressure is the sum of the partial pressures of the gases present.
- Therefore, Total Pressure = Partial Pressure of Hydrogen + Vapor Pressure of Water.
4. Calculate the Partial Pressure of Hydrogen:
- You can rearrange the formula to solve for the Partial Pressure of Hydrogen:
[tex]\[
\text{Partial Pressure of Hydrogen} = \text{Total Pressure} - \text{Vapor Pressure of Water}
\][/tex]
- Substitute the known values:
[tex]\[
\text{Partial Pressure of Hydrogen} = 97.1 \, \text{kPa} - 3.2 \, \text{kPa} = 93.9 \, \text{kPa}
\][/tex]
Therefore, the partial pressure of the hydrogen gas is 93.9 kPa.
This corresponds to option A: 93.9 kPa.
When a gas is collected over water, the total pressure inside the collecting bottle is a combination of the pressure of the gas itself and the vapor pressure of the water. This is expressed by Dalton's Law of Partial Pressures, which states that the total pressure is the sum of the partial pressures of each gas present.
Here's how we can solve this problem step-by-step:
1. Identify the Total Pressure:
- The total pressure in the collecting bottle is given as 97.1 kilopascals (kPa).
2. Identify the Vapor Pressure of Water:
- The vapor pressure of the water is given as 3.2 kilopascals (kPa).
3. Apply Dalton's Law:
- According to Dalton's Law, the total pressure is the sum of the partial pressures of the gases present.
- Therefore, Total Pressure = Partial Pressure of Hydrogen + Vapor Pressure of Water.
4. Calculate the Partial Pressure of Hydrogen:
- You can rearrange the formula to solve for the Partial Pressure of Hydrogen:
[tex]\[
\text{Partial Pressure of Hydrogen} = \text{Total Pressure} - \text{Vapor Pressure of Water}
\][/tex]
- Substitute the known values:
[tex]\[
\text{Partial Pressure of Hydrogen} = 97.1 \, \text{kPa} - 3.2 \, \text{kPa} = 93.9 \, \text{kPa}
\][/tex]
Therefore, the partial pressure of the hydrogen gas is 93.9 kPa.
This corresponds to option A: 93.9 kPa.
