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# 4 Dissolution/Solubility Questions

1. How much N2 can dissolve in water at 25'C if the N2 partial pressure is 585. Mm Hg?

2. Hexachlorophene is used in germicidal soalp. What is its molar mass if 0.640g of the compound, dissolved in 25.0 g of chloroform, produces a solution whose boiling point is 61.93 'C?

3. The enthalpy of solution of KClo3 in water is +41 kj/mol. Does the solubility of KClo3 increase or decrease as the temp increases?

4. Cigars are best stored in a "humidor' at 18'C and 55% relative humidity. This means the pressure of water vapor should be 55% of the vapor pressure of pure water at the same temp. The proper humidity can be maintained by placing a solution of glycerol [C3H5 (OH)3] and water in the humidor. Calculate the percentage by mass of glycerol that lowers the vapor pressure of water to the desired volume.

#### Solution Preview

Solve all 4 problems and SHOW all work to a final answer Please DO NO do if you do not show a final answer
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1. How much N2 can dissolve in water at 25'C if the N2 partial pressure is 585. Mm Hg?

This question is based on Henry's law
P = KHC
Henry's law constant value for N2 = 2865 atm/(mol/L)
585 mm Hg = ( 585 mmHg/760 mmHg )* 1 atm = 0.77 atm
=> 0.77 atm = 2865 atm/(mol/l)* C
=> C = 0.77 atm * (1/2865) atm-1 mol/l = 2.69 * 10-4 mol/l

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#### Solution Summary

Solution answers 4 questions on dissolving nitrogen, finding the molar mass from a boiling point, judging solubility as temperature increases and calculating percentage by mass. Attached as Word.

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