SOLVED

21) Which compound is most likely to be soluble in hexane? A) water B) acetone (CH3COCH3) C) benzene (C6H12) D) ethyl alcohol (CH3CH2OH) E) chloroform (CHCl3) 22) Which of the following pairs of liquids would form a nonideal solution? A) CHCl3 and (CH3)2CO B) C6H5-CH3 (toluene) and C6H6 (benzene) C) CH3CH2CH2OH and CH3CH(OH)CH3 D) H5C6-C6H5 (diphenyl) and C6H6 (benzene) 23) A solution is called “ideal” when: A) all intermolecular forces of attraction are the same, resulting in no net enthalpy change when the solution is formed from its components. B) the forces of attraction between solute molecules exceed those between solute and solvent molecules. C) the forces of attraction between solute and solvent molecules are somewhat smaller than between solute-solute molecules or solvent-solvent molecules. D) the forces of attraction between solvent molecules exceed those between solute and solvent molecules. E) the forces of attraction between solute molecules and solvent molecules are much smaller than between solute-solute molecules or solvent-solvent molecules. 24) Which of the following compounds has the highest solubility? A) CaCl2 B) SrI2 C) CaI2 D) MgI2 E) CaBr2 25) Which of the following organic substances is most readily soluble in water? A) benzene B) pyridine C) octane D) carbon tetrachloride E) toluene 26) Which of the following statements about ideal solutions is(are) true? I) Entropy effects are important for the formation of ideal solutions. II) The heat of solution is zero. III) The vapor pressure varies linearly with the composition. IV) The forces between like kinds of molecules are (almost) equal to the forces between unlike kinds of molecules. A) I), II), IV) B) I), III), IV) C) II), III), IV) D) I), II), III) E) I), II), III), IV) 27) A solution that can dissolve no more solute is called: A) unsaturated B) saturated C) concentrated D) supersaturated E) oversaturated 28) A crystal is placed into a solution and the solution seems to solidify while getting much warmer at the same time. The solution must have been: A) supersaturated B) dilute C) saturated D) unsaturated E) concentrated 29) The solubilities of ammonium bromide, NH4Br, in water at 0°C, 20°C, and 80°C are as follows: T (°C) Sol. g NH4Br/100 g H2O              0              60.5              20              76.4              80              125 Which of the following fractional crystallization schemes would produce the highest percent yield for the recrystallization of ammonium bromide? A) A solution containing 50.5 g NH4Br in 100.0 g H2O at 20°C is cooled to 0°C. B) A solution containing 115 g NH4Br in 200 g H2O at 80°C is cooled to 0°C. C) A solution containing 120 g NH4Br in 100 g H2O at 80°C is cooled to 20°C. D) A solution containing 100 g NH4Br in 100.0 g H2O at 80°C is cooled to 20°C. E) A solution containing 95 g NH4Br in 175 g H2O at 80°C is cooled to 0°C. 30) Henry’s Law states that: A) a supersaturated solution is unstable B) the solubility of a gas increases as the gas pressure is increased C) the solubility of a gas decreases as the gas pressure is increased D) a concentrated solution lowers the freezing point of a solution E) a concentrated solution increases the boiling point of a solution