What mass of Na2SO4 must be dissolved in 100.0 grams of wate…

What mass of Na2SO4 must be dissolved in 100.0 grams of water to lower the freezing point by 2.50°C? The freezing point depression constant, Kfp, of water is –1.86 °C/m. Assume the van’t Hoff factor for Na2SO4 is 2.85. a. 3.77 g b. 6.36 g c. 6.70 g d. 11.3 g e. 19.1 g

What is the vapor pressure at 20°C of an ideal solution prep…

What is the vapor pressure at 20°C of an ideal solution prepared by the addition of 4.60 g of the nonvolatile solute urea, CO(NH2)2, to 50.2 g of methanol, CH3OH?  The vapor pressure of pure methanol at 20°C is 89.0 mmHg. Assume that Raoult’s law applies. a. 4.15 mmHg b. 76.0 mmHg c. 81.5 mmHg d. 84.9 mmHg e. 13.0 mmHg