12.8 When 1.00 g of urea [CO(NH2)2] is dissolved in 200 g of solvent A, the A freezing point is lowered by 0.250°C. When 1.50 g of the nonelectrolyte Y is dissolved in 125 g of the same solvent A, the A freezing point is lowered by 0.200°C. (a) Find the molecular weight of Y. (b) The freezing point of A is 12°C, and its molecular weight is 200. Find Afus of A.

6-68 If we add 175 g of ethylene glycol, C2H6O2, per 1000. g of water to a car radiator, what will be the freezing point of the solution?

6-53 Dioxin is considered to be poisonous in concentrations above 2 ppb. If a lake containing L has been contaminated by 0.1 g of dioxin, did the concentration reach a dangerous level?

The freezing point of a 0.11 m solution of HNO2 is -0.20C. (a) What is i for the solution? (b) Is the solution made (i) of HNO2 molecules only? (ii) of H+ and NO2- only? (iii) of more HNO2 molecules than H+ ions? (iv) primarily of H+ and NO2- ions with some HNO2 molecules?

6-74 An osmotic semipermeable membrane that allows only water to pass separates two compartments, A and B. Compartment A contains 0.9% NaCI, and compartment B contains 3% glycerol C3H8O3. (a) In which compartment will the level of solution rise? (b) Which compartment (if either) has the higher osmotic pressure?

(a) If you dissolve 10.0 g (about one heaping teaspoonful) of sugar (sucrose, C12H22O11) in a cup of water (250. g), what are the mole fraction, molality, and weight percent of sugar? (b) Seawater has a sodium ion concentration of 1.08 104 ppm. If the sodium is present in the form of dissolved sodium chloride, what mass of NaCl is in each liter of seawater? Seawater is denser than pure water because of dissolved salts. Its density is 1.05 g/mL

Analysis of a compound gave 39.50% C, 2.21% H, and 58.30% Cl. When 0.855 g of this solid was dissolved in 7.50 g of naphthalene, the solution had a freezing point of 78.0C. The pure solvent freezes at 80.0C; its molal freezing point constant is 6.8C/m. a What is the molecular formula of the compound? b What is its molecular weight to the nearest 0.1 g?

Lauryl alcohol, C12H25OH, is prepared from coconut oil; it is used to make sodium lauryl sulfate, a synthetic detergent. What is the molality of lauryl alcohol in u solution of 17.1 g lauryl alcohol dissolved in 185 g ethanol, C2H3OH?

6-113 List the following aqueous solutions in order of decreasing freezing point: 0.040 M glycerin (C3H8O3) 0.025 M NaBr, and 0.015 M AI(NO3)3 Assume complete dissociation of any salts.

Some ethylene glycol, HOCH2CH2OH, is added to your cars cooling system along with 5.0 kg of water. If the freezing point of the water-glycol solution is 15.0 C, what mass of HOCH2CH2OH must have been added?