Chemistry 123 Quiz 7 Harwood/Fall 05
Name: Section #
1. Suppose that liquid A has stronger intermolecular forces than liquid B at room temperature.
(a) Which substance will have greater surface tension?
(b) Which substance will have the greater vapor pressure?
(c) Which substance will have the greater viscosity?
2. Calculate the boiling point of water at 24 mm Hg. (The ΔHvap of water is 40.7 kJ/mol.)
3. Solid lithium has a body-centered cubic unit cell with the length of the edge of 351 pm at
20°C. What is the density of lithium at this temperature?
4. The vapor pressure of ethanol, C2H5OH, at 50.0°C is 233 mm Hg and its normal boiling
point at 1 atm is 78.3°C. What is the ΔHvap of ethanol?
5. Halomethane, which had been used as an anesthetic, has the molecular formula
CHBrClCF3.
(a) Write the Lewis structure for halomethane,
(b) Is halomethane a polar molecule? Explain your answer.
(c) Does hydrogen bonding occur in halomethane? Explain.
6. In another universe, elements try to achieve a nonet (nine valence electrons) instead of an
octet when forming chemical bonds. As a result, covalent bonds form when a trio of
electrons is shared between two atoms. Two compounds in this other universe are H3O and
H2F. Draw their Lewis structure, then determine their electron-trio geometry and molecular
geometry.
