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Unformatted text preview: HW-12Answers to Chapter 12 questions4/30/02 Dr SJ Brois 12.32 Vinegar is a 5% solution of acetic acid in water. The density of vinegar is 1.0055 g/ml. Express the conc of acetic acid as a. molality, b. molarity, and c. mole fractiona. A 5% soln corresponds to 5 g of acetic acid in 100 g solutionMols of acetic acid = 5/60 = .083 a. Molality = moles/kg solvent = .083/0.095 kg = 0.87 mb. Molarity = mol/L 0.083/0.1 = 0.83 Mc. Mole fraction = mol acetic acid/mol acetic acid + mol water = 0.083/ 0.083 + 5.28 = 0.083/5.363 = 0.01512.42 Predict the relative solubility of each compound in the two solvents on the basis of intermolecular attractions.a.Is NaCl more soluble in water or CCl4NaCl is ionic and is water soluble. It wouldn’t be soluble in nonpolar solventsb.Is I2 more soluble in water or benzeneIodine is nonpolar and owing to London forces, is soluble in benzenec. Is EtOH more soluble in water or in hexaneEthanol is polar and can H bond with water. Hexane is nonpolar.d. Is ethylene glycol more soluble in in ethanol or benzene?Ethylene glycol is polar and can H bond with water. Benzene is nonpolar.112.54 At 25 C and 2 atm the enthalpy of solution of neon in water is –2.46 kJ /mol and its solubility is 9.07 x 10-4 m. State whether the solubility of neon is greater or less than is 9.07 x 10-4 m under each of the following conditions.a. 0◦C and 3 atm. b. 25◦C and 1 atm……c. 10◦C and 2 atm d. 50◦C and 2 atm e. 50◦C and 1.5 atma. lower T and higher P enhances solubilityb. same T and lower P lowers solubilityc. lower T and same P enhances solubilityd. higher T and sameP lowers solubilitye.higher T and lower P lowers solubility12.60 The enthalpy of solution of nitrous oxide in water is –12 kJ/mol and its solubility at 20◦C and 1 atm is 0.121 g per 100 g of water.a.What is the Henry’s Law constant in molal/torr at 20◦C?b.At 10◦C and 1 atm, would the Henry’s law constant be larger, smaller or the same as it is at 20◦C and the same pressure....
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- Spring '09
- mol, Nitrous oxide, mols, PWA, Dr SJ Brois