Of the following (a through e), which increase and which decrease, as the strength of the attractive noncovalent interactions increases? Explain.

a) Deviations from the ideal ga law
b) Boiling Temperature
c) Sublimation temperature
d) Vapor Pressure
e) The energy it takes to vaporize 1 mol of the substance.

To determine how each of the given properties (a through e) changes with the increase in the strength of attractive noncovalent interactions, we need to understand the concept behind these properties and how they are influenced by intermolecular forces.

a) Deviations from the ideal gas law: The ideal gas law describes the behavior of ideal gases under standard conditions, in which the gas particles do not interact with each other. However, in real gases, intermolecular forces can cause deviations from the ideal gas behavior. As attractive noncovalent interactions increase, the gas particles are more likely to come closer together, leading to deviations from the ideal behavior.

b) Boiling temperature: Boiling temperature is the temperature at which a substance changes from a liquid to a gas phase. Stronger attractive noncovalent interactions result in stronger intermolecular forces, making it more difficult for the particles to overcome these forces and escape into the gas phase. Therefore, as the strength of attractive noncovalent interactions increases, the boiling temperature tends to be higher.

c) Sublimation temperature: Sublimation is the process in which a substance transitions directly from the solid phase to the gas phase without passing through the liquid phase. If the substance exhibits significant attractive noncovalent interactions, the particles are strongly held together in the solid phase, requiring more energy to break these forces during sublimation. Hence, as the strength of attractive noncovalent interactions increases, the sublimation temperature generally increases.

d) Vapor pressure: Vapor pressure is the pressure exerted by the gaseous phase of a substance in equilibrium with its liquid or solid phase at a given temperature. Stronger attractive noncovalent interactions hinder the escape of particles from the liquid or solid phase to the gas phase, resulting in a lower vapor pressure. Therefore, as the strength of attractive noncovalent interactions increases, the vapor pressure tends to decrease.

e) The energy it takes to vaporize 1 mol of the substance: The energy required to vaporize 1 mol of a substance is known as the molar heat of vaporization. This energy is needed to overcome the intermolecular forces holding the substance together in the liquid phase and convert it into the gas phase. As the strength of attractive noncovalent interactions increases, more energy is required to break these forces and vaporize the substance. Consequently, the molar heat of vaporization increases.

In summary, as the strength of attractive noncovalent interactions increases:
a) Deviations from the ideal gas law increase.
b) Boiling temperature tends to increase.
c) Sublimation temperature tends to increase.
d) Vapor pressure tends to decrease.
e) The energy required to vaporize 1 mol of the substance increases.