What is the vapor pressure of an aqueous solution that has a solute mole fractio

Question

What is the vapor pressure of an aqueous solution that has a solute mole fraction of 0.1? The vapor pressure of water is 25.756 mmHg at 25 oC (assume nonvolatile solute).

the vapor pressure of an aqueous solution 24.90mmHgat25 oC. What is the mole fraction of solute in this solution? The vapor pressure of water is 25.756 mmHg at 25 oC (assume nonvolatile solute).

How many grams of nonvolatile compound B(M.M.=97.80g/mol)would need to be added to 250.0 g of water to produce a solution with a vapor pressure of 23.756 torr? The vapor pressure of pure water at this temperature is 42.362 torr (assume nonvolatile).

*please write in clear handwriting or type it (thank you)

Explanation / Answer

vapor pressure of the solution (p) = mole fraction of the solvent (x solv)* vapor pressure of pure solvent (P*)

or, p = 0.9* 25.756 mmHg (as x solv + x solute = 1; and x solute = 0.1)

or, 23.1804 mmHg

similarly, p = x solvent * P*

or,  = 24.90 / 25.756 = 0.97

so, mole fraction of solute will be = 1 - 0.97 = 0.03

again, x solvent = 23.756 torr / 42.362 torr = 0.56

so, x solute = 1- 0.56 = 0.44

x solute = mole of solute / total mole

mole of solute = weight taken (gm) / 97.80g/mol = b gm/ 97.80g/mol

mole of water = 250 gm / 18 gm = 13.89 mole

total mole = ( b gm/ 97.80g/mol) + 13.89

hence, x solute = 0.44 = (b gm/ 97.80g/mol) / ( b gm/ 97.80g/mol) + 13.89)

or, b = 1067.3 gm (answer)

Related Questions

Navigate

• Browse (All)
• Browse W
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.