Calculating Vapor Pressure Lowering for Glucose-Water Solution at 25oC

The actual value is 0.996.In summary, the conversation discusses the calculation of vapor pressure lowering in a solution containing 82.0 g of glucose in 322 g of water at 25oC. The molar fraction of solvent in the solution is found to be 0.985 and the final result for vapor pressure lowering is 0.348 mmHg. The process is deemed correct with the exception of a math error in the calculation of the mole fraction.
  • #1
amcavoy
665
0
A solution contains 82.0 g of glucose (C6H12O6) in 322 g water. Calculate the vapor pressure lowering at 25oC. The vapor pressure of pure water at 25o is 23.76 mmHg.

I calculated that there is 41/90 mol glucose and 92/3 mol water. Then I calculated the molar fraction of solvent in the solution, which I found to be .985. Next I multiplied the .985 by 23.76 mmHg and came up with 23.4 mmHg. To find the "lowering," I subtracted this from 23.76 coming up with a final answer of .348 mmHg.

Assuming I didn't make any arithmetic errors, is my process correct?

Thank you.
 
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  • #2
amcavoy said:
Assuming I didn't make any arithmetic errors, is my process correct?
Yes. There is a math error in the calculation of the mole fraction.
 

1. What is vapor pressure lowering?

Vapor pressure lowering is a phenomenon in which the vapor pressure of a liquid is reduced when a non-volatile solute is added to it.

2. How does vapor pressure lowering occur?

Vapor pressure lowering occurs due to the decrease in the number of solvent molecules at the surface of the solution, as the solute molecules take up space and prevent the solvent molecules from escaping as easily.

3. What factors affect vapor pressure lowering?

The amount of solute added, the nature of the solute and solvent, and temperature are the main factors that affect vapor pressure lowering.

4. What is the significance of vapor pressure lowering?

Vapor pressure lowering is important in many industrial and environmental processes, such as boiling point elevation, osmosis, and atmospheric pollution.

5. How is vapor pressure lowering calculated?

Vapor pressure lowering can be calculated using Raoult's Law, which states that the vapor pressure of a solution is equal to the vapor pressure of the pure solvent multiplied by the mole fraction of the solvent in the solution.

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