Final answer:
The pressure of carbon dioxide is calculated by subtracting the vapor pressure of water from the total pressure. After converting torr to atm for the water vapor pressure, you subtract this from the total pressure to find the pressure of the carbon dioxide. Dalton's Law of Partial Pressures is the gas law used in this case.
Step-by-step explanation:
The question asks for the pressure of carbon dioxide collected over water at a specific temperature and total pressure. To find the pressure of just the carbon dioxide, we need to subtract the vapor pressure of water at the given temperature from the total pressure of the gas mixture.
The total pressure of the gas mixture is 0.789 atm, and the vapor pressure of water at 35 °C is 42.2 torr. To compare these values, they must be in the same units. since 1 atm = 760 torr, we can convert 42.2 torr to atmospheres: 42.2 torr × (1 atm / 760 torr) = 0.0555 atm. Now we can subtract this from the total pressure to find the pressure of the carbon dioxide alone: 0.789 atm - 0.0555 atm = 0.7335 atm. However, this is not one of the options provided, indicating there might be a typo in the question or the provided answer options. Assuming this is a typo, the closest provided answer is 0.747 atm.
The gas law being applied here is Dalton's Law of Partial Pressures, which states that the total pressure of a mixture of gases is equal to the sum of the pressures of each individual gas in the mixture, with each gas acting independently.