*I know this worksheet has some answers but I don\'t know how did they reach thi

Question

*I know this worksheet has some answers but I don't know how did they reach this answer

can you please write the whole answer (on paper with clear handwriting or type it ) thank you

1. When a solute is added to a solvent, does the vapor increase, decrease or 2. What is the difference in Raoult's law if the solute is volatile compared to 3. Are the mole fractions in the vapor and the solution the same? stay the same? Why? being nonvolatile? water at 25 °C is 23.76 torr, what will the pressure of the solution be? ANS- 4. 3 moles of sugar was added to 15 moles of water. If the pressure of pure 19.6 torr 5. 36 g of calcium chloride (nonvolatile) was added to 107 g of water. If the pressure of pure water at 25 °C is 23.76 torr, what will the pressure of the solution be? ANS = 22.57 torr 6. 6.7 g of barium sulphate (nonvolatile) was added to 507 cm3 of water. If the pressure of pure water at 25 °C is 23.76 torr and its density is 0.9971 g/cm what will the pressure of the solution be? ANS 23.74 torr 7. 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 °C (assume nonvolatile solute). ANS 23.18 mmHg 8. The vapor pressure of an aqueous solution is found to be 24.90 mmHg at 25 °C. What is the mole fraction of solute in this solution? The vapor pressure of water is 25.756 mmHg at 25 °C (assume nonvolatile solute). ANS 0.03

Explanation / Answer

1. vapor pressure will decrease.

When a solute is added to the solvent, some of the solute molecules occupy the space near the surface of the liquid, the number of solvent molecules near the surface decreases, and the vapor pressure of the solvent decreases.

2. here total vapor pressure will be the sum of partial pressure of both volatile solvent and solute.

3. no, mole frcation will not same in the vapor and solution, more volatile componant has more mole in vapor phase.

4. pressure of the solution = mole fraction of solvent * pressure of pure solvant

here, sugar is the non-volatile solute.

so, mole fraction of water = 15 /(15+3) = 0.83 and pressure of pure water = 23.76 torr.

so, pressure of the solution = 0.83* 23.76 torr = 19.72 torr

5. mole of solute = 36/ 111 = 0.32 ( molecular weight of calcium chloride = 111 gm)

mole of water = 107 /18 = 5.94

mole fraction of water = 5.94 /(5.94+0.32) = 0.95

so, pressure of the solution = 0.95*23.76 torr = 22.57 torr

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