In what situation would vapor pressure increase?

Vapor pressure is the pressure exerted by a vapor in thermodynamic equilibrium with its condensed phases at a given temperature. When the temperature of the liquid phase increases, the molecules gain kinetic energy, which allows a higher number of them to overcome intermolecular forces and escape into the vapor phase. This results in an increase in vapor pressure.

Additionally, when atmospheric pressure decreases, it means there’s less external pressure acting on the liquid. In this situation, the equilibrium shifts to favor more molecules converting into vapor to counterbalance the reduced external pressure, thus also leading to an increase in vapor pressure.

The combination of these two factors—rising temperature and decreasing atmospheric pressure—contributes to an overall increase in vapor pressure. Therefore, the correct answer encompasses both scenarios, making it accurate that both the rise in temperature and the decrease in atmospheric pressure lead to an increase in vapor pressure.