CHM 1046 Exam 1 Questions With Guaranteed Correct Answers

T/F: CH2F2 has a higher melting point than CH3Cl - correct answers True T/F: Molecules with polar bonds are polar - correct answers False T/F: If a scuba diver ascends too quickly to the surface, immediately putting them in a fridge would help hinder the cause of "the bends" (AKA decompression sickness) - correct answers True T/F: K+ is more soluble in water than Be2+ - correct answers False T/F: Boiling point is a more universal metric to describe intermolecular forces than the molar heat of vaporization - correct answers False T/F: For a polar molecule, adhesive forces are always greater than cohesive forces - correct answers False T/F: There is linear relationship between the temperature and the solubility of a gas. - correct answers False T/F: There are no examples of the solubility of a solid decreasing with increasing temperature - correct answers False T/F: Solutions will boil when their vapor pressure surpasses the external pressure. - correct answers True T/F: A solution composed of pentane and hexane has a mole fraction, X= .250 of pentane. Pentane is the solvent. - correct answers False T/F: You could force a solution to boil at lower temperature by either decreasing the external pressure, adding more heat, or somehow decreasing the delta Hvap. - correct answers False Assuming they were all liquid, in terms of initial impact, which one would hurt the least to dive into? A. HCl B. F2 C. COH2 D. HF E. CS2 - correct answers B. F2 Methane has a heat fusion of .84 kJ/mol and a heat vaporization of 9.2 kJ/mol. Approximately how much energy would it take to sublime 2 moles of methane? A. 20 Kj B. 15 Kj C. 10 kJ D. 8 kJ - correct answers A. 20 kJ The vapor pressure of a liquid in a closed container depends upon A. the amount of liquid B. the surface area of the liquid C. the volume of the container D. the temperature E. b and d - correct answers D. the temperature Which of the following phase changes release energy? A. sublimation B. condensation C. melting D. vaporization E. none of the above - correct answers B. condensation Which of the following can form hydrogen bonds with water molecules? 1. Na+ 2. CH3COOH 3. C2H6 4. CH3NH2 A. 1 and 2 B. 1 and 3 C. 2 and 3 D. 2 and 4 E. 3 and 4 - correct answers D. 2 and 4 Which of the following concentration units is temperature dependent? A. percent mass B. mole fraction C. molality D. molarity E. none of the above - correct answers D. molarity Which of the following substances has the highest polarizability? A. CH4 B. H2 C. SF6 D. H2S - correct answers C. SF6 There is a trigonal planar molecule with one atom missing. (B atom in middle, 2 F atoms on bottom, one missing on top) Which atom(s) would you add to make a neutral compound that is miscible in CCl4? A. H B. F C. B D. a and b E. a and c - correct answers B. F There is a trigonal planar molecule with one atom missing. (B atom in middle, 2 F atoms on bottom, one missing on top) Which atom(s) would you add to make a neutral compound that is soluble in H2S?