Problem: A solution contains 5.00 g of urea, CO(NH2)2, a nonvolatile compound, dissolved in 0.100 kg of water. If the vapor pressure of pure water at 25 °C is 23.7 torr, what is the vapor pressure of the solution?

FREE Expert Solution

Vapor Pressure Lowering is a colligative property which describes the decrease in vapor pressure of a solution when a solute is added to a solution.

The formula for vapor pressure lowering is:

Psolution=χsolvent·P°solvent

 Where:

Psolution is the vapor pressure of the solution

solvent is the vapor pressure of pure solvent

Xsolvent is the mole fraction of the solvent


Solve for the mole fraction of the solvent:

χsolvent=molsolventι·molsolute+molsolvent

 

Moles of solute (urea):

5.00 g urea(1 mol urea60.06 g urea)=0.083 moles

Moles solvent (water):

Recall: 1 kg = 103 g

0.100 kg(103 g1kg)(1 mol H2O18.016 g H2O)=5.55 moles

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Problem Details

A solution contains 5.00 g of urea, CO(NH2)2, a nonvolatile compound, dissolved in 0.100 kg of water. If the vapor pressure of pure water at 25 °C is 23.7 torr, what is the vapor pressure of the solution?

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What scientific concept do you need to know in order to solve this problem?

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

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

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Our data indicates that this problem or a close variation was asked in Chemistry - OpenStax 2015th Edition. You can also practice Chemistry - OpenStax 2015th Edition practice problems.