Problem: Pentane (C5H12) and hexane (C6H14) form an ideal solution. At 25°C the vapor pressures of pentane and hexane are 511 and 150. torr, respectively. A solution is prepared by mixing 25 mL pentane (density, 0.63 g/mL) with 45 mL hexane(density, 0.66 g/mL).b. What is the composition by mole fraction of pentane in the vapor that is in equilibrium with this solution?

🤓 Based on our data, we think this question is relevant for Professor Ochoa's class at UCD.

FREE Expert Solution
FREE Expert Solution

We’re being asked to calculate the mole fraction of pentane in the solution. 

The solution was prepared by mixing 25 mL pentane (density, 0.63 g/mL) with 45 mL hexane (density, 0.66 g/mL).

Pentane → lesser in amount → solute
Hexane → greater in amount → solvent

Mole Fraction (X) relates the moles of solute and solvent within a solution:

mole fraction (X)=mole of solutemole of solution


We’ll calculate the mole fraction of pentane using the following steps:

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Problem Details

Pentane (C5H12) and hexane (C6H14) form an ideal solution. At 25°C the vapor pressures of pentane and hexane are 511 and 150. torr, respectively. A solution is prepared by mixing 25 mL pentane (density, 0.63 g/mL) with 45 mL hexane
(density, 0.66 g/mL).

b. What is the composition by mole fraction of pentane in the vapor that is in equilibrium with this solution?

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Our tutors have indicated that to solve this problem you will need to apply the Mole Fraction concept. You can view video lessons to learn Mole Fraction. Or if you need more Mole Fraction practice, you can also practice Mole Fraction practice problems.

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Our tutors rated the difficulty ofPentane (C5H12) and hexane (C6H14) form an ideal solution. A...as medium difficulty.

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Our expert Chemistry tutor, Sabrina took 5 minutes and 20 seconds to solve this problem. You can follow their steps in the video explanation above.

What professor is this problem relevant for?

Based on our data, we think this problem is relevant for Professor Ochoa's class at UCD.

What textbook is this problem found in?

Our data indicates that this problem or a close variation was asked in Chemistry: An Atoms First Approach - Zumdahl 2nd Edition. You can also practice Chemistry: An Atoms First Approach - Zumdahl 2nd Edition practice problems.