Question

An aqueous CaCl2 solution has a vapor pressure of 80.2 mmHg at 50 ∘C. The vapor pressure of pure water at this temperature is 92.6 mmHg. What is the concentration of CaCl2 in mass percent?

A hypothetical solution forms between a solid and a liquid. The values of the thermodynamic quantities involved in the process are shown in the following table.

Action	Enthalpy
separation of solute	11.5 kJ/mol
separation of solvent	21.8 kJ/mol
formation of solute-solvent interactions	-86.7 kJ/mol solute

Calculate the enthalpy of solution in kilojoules per mole of solute.

Enter your answer numerically in kilojoules per mole of solute.

Calculate the molarity of KCl in the solution if the total volume of the solution is 239 mL.

Calculate the molality of KCl in the solution.

How much dioxin is present in 2.6 L of this water? Assume a density of 1.00 g/mL.

At 25.0∘C, the molar solubility of barium chromate in water is 1.10×10⁻⁵ M . Calculate the solubility in grams per liter.

One brand of laundry bleach is an aqueous solution containing 4.00% sodium hypochlorite (NaOCl)by mass. What is the molarity of this solution? (Assume a density of 1.02 g/mL.)

If 0.280 mol  of a nonvolatile nonelectrolyte are dissolved in 3.30 mol of water, what is the vapor pressure PH2O of the resulting solution? The vapor pressure of pure water is 23.8 torr at 25 ∘C .

Cyclohexane has a freezing point of 6.50 ∘C and a Kf of 20.0 ∘C/m. What is the freezing point of a solution made by dissolving 0.617 g of biphenyl (C12H10) in 25.0 g of cyclohexane?

Answer 1

We know that here, ,soltin is vapor pressure of solution, יז,ert Is vapor pressure of pure water and ,het is the mole fraction of water Given tin 80.2 mmHg at92.6 mmHg Caluclate the value of ot as follows ohtim ”ret 80.2 mmHg "ret _ 92.6 mmHg e0.866 Let the total moles be 100 moles moles of solvent 0.866x100 moles 86. 6moles moles of solute= (1-0.866)×100 moles 13.4moles CaCl2 dissolves in water as Ca and Cl, total three ions and thus the vant Hoff factor is 3 So the moles of CaCl2 will - rd of the solute moles of Cacl(134moles) 4.47 moles 110.983-496g mass of CaCl2 - 4.47 molesx mass of H20 86.6 molesx1558.8 g Mass % of CaC12- mol 18 g mol mass of CaCl mass of CaC mass of H.O ×100 496 g x100 496 g +1558.8 g 24.190 Therefore, the required solution is 241%)