Question

Explain what vapor pressure is and does water have high or low vapor pressure for its size?

Answer 1

• When a solid or a liquid evaporates to a gas in a closed container, the molecules cannot escape.
• Some of the gas molecules will eventually strike the condensed phase and condense back into it.
• When the rate of condensation of the gas becomes equal to the rate of evaporation of the liquid or solid, the amount of gas, liquid and/or solid no longer changes.
• The gas in the container is in equilibrium with the liquid or solid.
• The pressure exerted by the gas in equilibrium with a solid or liquid in a closed container at a given temperature is called the vapor pressure.
• The vapor pressure of a liquid varies with its temperature.As the temperature of a liquid or solid increases its vapor pressure also increases. Conversely, vapor pressure decreases as the temperature decreases.

Hydrogen bonding exist within water molecules. This hydrogen bonding raises the vapor pressure of water. Hence, we can say that water has high vapor pressure.