Answer :
Final answer:
The vapor pressure of an ideal solution formed by heptane and octane at 373 K is the sum of the partial pressures of each component. Based on Raoult's law, the total vapor pressure is calculated to be 64.32 kPa, which does not match the answer choices provided.
Explanation:
The vapor pressure of an ideal solution of heptane and octane can be calculated using Raoult's law, which states that the total vapor pressure of an ideal solution is equal to the sum of the products of the mole fractions of the components and their respective vapor pressures. In this case, the vapor pressures of heptane and octane at 373 K are 105.2 kPa and 46.8 kPa. The vapor pressure of heptane in the solution is the mole fraction of heptane times its vapor pressure, and the vapor pressure of octane in the solution is the mole fraction of octane times its vapor pressure. The total vapor pressure of the solution is the sum of these two partial pressures.
- Calculate the mole fraction of heptane: 0.300 mole / (0.300 mole + 0.700 mole) = 0.3.
- Calculate the partial vapor pressure of heptane: 0.3 x 105.2 kPa = 31.56 kPa.
- Calculate the mole fraction of octane: 0.700 mole / (0.300 mole + 0.700 mole) = 0.7.
- Calculate the partial vapor pressure of octane: 0.7 x 46.8 kPa = 32.76 kPa.
- Add the partial pressures to find total vapor pressure: 31.56 kPa + 32.76 kPa = 64.32 kPa.
Thus, the vapor pressure of the ideal solution formed by mixing heptane and octane is 64.32 kPa. However, since the options for the answer include values around 152 kPa, it seems there might be a discrepancy in the provided data or a misunderstanding in the question. The calculations based on the given vapor pressures at 373 K do not match the answer choices provided.
