The Nature of Liquids

1
The Nature of Liquids
2
Overview

• Liquids vs. Gases
• Kinetic Energy
• Intermolecular Forces

• Vaporization
• Evaporation
• Vapor Pressure
• Boiling Point

3
Liquids vs. Gases

• Kinetic Energy
• Density
• Volume
• Compressibility

4
Kinetic Energy

• Kinetic energy is the energy of motion
• In a liquid, the particles are free to slide past
  each other
• Kinetic energy keeps the molecules apart an
  moving around

5
Kinetic Energy

• Particles in a liquid do not have enough kinetic
  energy to escape into the gaseous state

6
Intermolecular Forces

• In a liquid, the intermolecular forces are strong
  enough to hold the molecules close together
• The intermolecular forces reduce the amount of
  space between particles

7
Intermolecular Forces
8
Manometer

• Manometers are used to measure pressure
• The most common design is to bend a glass tube
  into a U shape
• The curved end is always placed at the bottom

9
Manometer Setup

• A vacuum is created in the sealed end of the tube
• The open end of the tube is then connected to the
  subject whose pressure is being measured

10
Manometer Use

• In the sealed end of the tube, there is no gas to
  exert force
• In the open end, the pressure of the subject
  exerts force on the mercury, causing it to rise
• The difference in the height of the mercury in
  the left tube and the right tube equals the
  pressure of the subject

11
Manometer
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12
Evaporation

• Evaporation is the process whereby atoms or
  molecules in a liquid state gain sufficient
  energy to enter the gaseous state. Most notably,
  for a liquid to boil, its vapor pressure must
  equal the ambient pressure, whereas for
  evaporation to occur, this is not the case.

13
Evaporization
14
Vaporization

• The process that occurs when a substance converts
  from a liquid or a solid to a gaseous state. If
  conditions allow the formation of vapor bubbles
  within a liquid, the vaporization process is
  called boiling.

15
Vaporization
16
Acknowledgments

• Megan Brown
• Brian Matty
• Danielle Conn
• Steve Ward
• Chemistry Addison-Wesley Textbook