Question

based on the information in the table above, which liquid, cs₂(l) or ccl₄(l), has the higher equilibrium vapor pressure at 25°c, and why?
(a) cs₂(l), because it has stronger london dispersion forces
(b) cs₂(l), because it has weaker london dispersion forces
(c) ccl₄(l), because it has stronger london dispersion forces
(d) ccl₄(l), because it has weaker london dispersion forces
of the following, the best explanation for the fact that most gases are easily compressed is that the molecules in a gas are in constant motion

Explanation:

London dispersion forces are stronger in molecules with larger molar masses. \(CCl_4(l)\) has a higher molar mass (\(154\ g/mol\)) compared to \(CS_2(l)\) (\(76\ g/mol\)). Stronger London dispersion forces mean higher boiling points (since more energy is needed to overcome these forces) and lower equilibrium vapor pressures (as fewer molecules can escape the liquid phase). Since \(CS_2(l)\) has a lower boiling point (\(46.5^{\circ}C\) vs \(76.7^{\circ}C\) for \(CCl_4(l)\)), it has weaker London dispersion forces.

Answer:

B. \(CS_2(l)\), because it has weaker London dispersion forces