Question

massa volum volum mo olu 5. In which of the following solvents would you expect KBr to be most soluble? a) CH4 (hexane) d) CCM (carbon tetrachloride) b) CH CH OH (ethanol) e) C.Hz (cyclohexane) c) CH. (benzene) ___6. A 9.50 % by mass solution of acetone (C,H,O) in water has a density of 0.9849 g/mL at 20°C. What is the molarity of this solution? a) 0.621 M b) 1.61 Me) 1.66 Md ) 1.71 M e ) 16.9 M 7. The solubility of Co, gas in water a) increases with increasing temperature. b) decreases with decreasing temperature. c) decreases with increasing temperature. d) is not dependent on temperature. 8. Consider a 0.90 M AI(NO), solution. This solution has a nitrate ion concentration of a) 0.30M b) 0.90 M €) 0.0 M d) 8.1 M e) 2.7 M 9. What is the mass percent CH OH of a 0.256 m CH,OH(aq) solution. a) 0.814 % b) 0.992 % c) 1.23% d) 1.29% e) 1.51% 10. According to Raoult's law, which statement is false? a) The vapor pressure of a solvent over a solution decreases as its mole fraction increases. b) The solubility of a gas increases as the temperature decreases. c) The vapor pressure of a solvent over a solution is less than that of pure solvent. d) The greater the pressure of a gas over a solution the greater its solubility. e) Ionic solutes dissociate in solution causing an enhancement of all colligative properties 11. Consider a solution made from a nonvolatile solute and a volatile solvent. Which statement is true? a) The vapor pressure of the solution is always greater than the vapor pressure of the pure solvent. b) The boiling point of the solution is always greater than the boiling point of the pure solvent. c) The freezing point of the solution is always greater than the freezing point of the pure solvent. 12. Dissolving a solute such as KOH in a solvent such as water results in a) an increase in the melting point of the liquid. b) a decrease in the boiling point of the liquid. c) a decrease in the vapor pressure of the liquid. d) no change in the boiling point of the liquid. Page 2

Answer 1

5 we know that KBr is an ionic Compound (kt Br). So it (KBR) is also Knon as polar sonic compound. we know that like dissolve like. It means that Polar Solute always dissolve in polar solvent Since KBr is Polar solute So KBX wis dissolve in polar solvents and - KBr will most souble in most polar solvent Among given solvents such as Chin (hexane), corn (carbon tetrachloride CGHz (Cyclohexane) and benzenet (C6H6) are non- Polar solvents. CH3CH2OH (ethanol) is Polar solvent due to presence of Polar oH) group. Hence, KBr is expected to be most Soluble in ethanol (CH3CH2OH) bcoz dike dissone like. Answer - 6

density.or Solution of acetone - -o.984991m. assume volume s solution of acet = 1L=1000ML we know that density - mass 9 - Volume mass of density of acetone acetone solution solution Volume of solution o.9849 g ent mas mass of acetone soluti looo nt lution mass of acetone solution = mass of acetone soluzion 0,9849x1000 g 1984.gg since mass of acetone is mass of of 9.50% solution. the so, mass of acetone = 9.50% of 984.gg mass of acetone = 9.50x984.gg mass of acetone = 93.579 we know thout Molecular weight of acetone - 58.08 g/mole Mole of acetone = Mole of acetone = given mass of acetone Molecular mass of acetone 93.57 8. 8 — 1. 4) Хе 58.08 8l mode moles of acetone = [1.6ignole

Since, molarity (m 2 = moles of solute volucre of solution in L Molarity of acetone = moles of acetone Volume of acetone solution (Ly holarity of acetone = 1.61 mole. -= 1.61M Hence Molarity of acetone = 1.61 ML Answer -