1. Ch. 13.2 The Nature of Liquids
Chemistry

2. A Model for Liquids
Molecules of both gases and liquids have kinetic energy so they can flow past one another. Substances that can flow are fluids. This ability to flow allows gases and liquids to take the shape of the container they are in.
The key difference between gases and liquids are the attraction in liquids keep the particles closer together, whereas in a gas there is no attraction. This attraction give liquids a definite volume.

3. Liquids are much more dense than gases
Liquids are much more dense than gases. Also increasing pressure on a liquid hardly has any effect on its volume. This is also true for solids. Liquids and solids are called condensed states of matter.

5. Evaporation
Vaporization is the conversion of a liquid to a gas or vapor.
When vaporization occurs at the surface of a liquid that is not boiling then it is called evaporation.
During evaporation, only molecules with a certain minimum kinetic energy can escape from the surface of the liquid.

7. A liquid will evaporate faster when heated
A liquid will evaporate faster when heated. Heating a liquid increases the average kinetic energy. This allows the particles to move faster and overcome the force of attraction. As particles escape the temperature of the liquid decreases because the fastest moving particles leave. This makes evaporation a cooling process.

9. Boiling Point and Pressure Changes
A liquid will boil when its vapor pressure is equal to the external pressure. This means you can change the temperature a liquid boils at.
Altitude can change the boiling point of water. Atmospheric pressure is lower at high altitudes so the boiling point decreases at higher altitudes. When pressure increases, like in using a pressure cooker, the boiling point is increased. In a pressure cooker this allows things to cook at higher temperatures and therefore faster.

11. Boiling is also a cooling process because the particles with the highest kinetic energy leave first. When a liquid is boiling though the temperature will never go above boiling. If you add more heat it will cause the liquid to boil faster.
The normal boiling point is the boiling point of a liquid at a pressure of kPa. For example the normal boiling point of water is 100 degrees Celcius.