# chemistry - vapor pressure

the vapor pressure of pure water at 25C is 23.8 torr. determine the vapor pressure (torr) of water at 25 C above a solution prepared by dissolving 35g of urea (a nonvolatile, non-electrolyte, MW = 60.0G/MOL) IN 76G of water.

i just want to know the steps bc im confused... help?

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1. Step 1. Determine mole fraction water.
a. moles urea = grams/molar mass = 35/60 = 0.583
b. moles H2O = 76/18 = 4.222
c. total moles = 4.805
d. XH2O = 4.222/4.805 = ??

Step 2.
Psoln = Xsolvent*Posolvent
where Po = normal vapor pressure of the solvent.

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2. lwjbjsovkpkgphjighbbbbbfwigaglgqapökpegjkopsjhwogjhropprshkpslbpgs

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3. How many grams of sucrose Akerla (molar mass -342 g / mol) must be added to 450 grams of water (molar mass 18.0 g / mol) to change the vapor pressure to 745 mm Hg at 100

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4. a) What is the composition in mole fractions of a solution of benzene and toluene that has a vapor pressure of 35 torr at 20 °C? Assume the mixture forms an ideal solution. The vapor pressure of benzene (C6H6) is 75 torr and the vapor pressure of toluene (C7H8) is 22 torr at 20 °C.

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5. 21

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