Ideal Gas Laws

1
Ideal Gas Laws

1. What causes gas pressure in a closed container?
2. What factors effect the pressure of an enclosed
   gas?

2
Day 1 What is an Ideal Gas?

• No gas behaves exactly like an ideal gas but it
  is a good model for making predictions.
• The Kinetic Theory of Matter (all matter is made
  of tiny, moving particles) explains the behavior
  of gasses.
• An ideal gas
• Particles in a gas are in constant and random
  motion.
• The motion of one particle is unaffected by
  another unless they collide.
• Forces of attraction among particles can be
  ignored under ordinary conditions.

3
Day 1 Gas and Pressure

• Pressure is the result of force distributed over
  an area.
• Collisions between particles of a gas and the
  walls of the container cause the pressure in a
  closed container.
• The more frequent the collisions, the greater the
  pressure of the gas.

4
Day 2 Factors That Effect Pressure

• Temperature of a gas will ____________ its
  pressure.
• __________ the volume of a gas will increase its
  pressure
• _________ the number of particles in a gas will
  increase the pressure of the gas.

increase
Reducing
Increasing
5
Day 2 Problem

• 1. Use the diagram below to determine how much
  does pressure goes up when the volume is
  decreased by one-half? One-Third?

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Day 2 Answer

1. When volume decrease by one-half pressure
   increase by two times.
2. When volume decrease by one-third pressure
   increases by 3/2 times. (Inverse relationship)

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Day 3 Gas Laws

• Charles Law states that the volume of a gas is
  directly proportional to its temperature, when
  pressure and the number of particles in a gas is
  held constant.
• Boyles Law states that the volume of a gas is
  inversely proportional to its pressure when
  temperature and the number of particles is held
  constant
• P1V 1 P2V2

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Day 3 Combined Gas Law

• Combined Gas Law (where n the number of gas
  particles.)

9
Day 3 ProblemsUse the Gas Laws to graph the
following relationships.
Pressure
Volume
Temperature
Volume
10
Day 4 Review

• 1. Use the kinetic theory of matter to explain
  why the pressure of a gas increases when its
  temperature increases?
• 2. If temperature doubles what happens to volume
  if everything else stays constant? Which of the
  gas laws applies in this case?
• 3. If volume doubles what happens to pressure if
  everything else stays constant? Which of the gas
  laws do you use in this case?
• 4. If the number of particles doubles in a gas
  what happens to the pressure? Which law did you
  use?

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Day 4 Answers

• 1. As the molecules or atoms in the gas are
  heated they move faster, spread out and collide
  more often with the sides of the container
  increasing the pressure on the container.
• 2. According to Charles's Law temperature volume
  will double if temperature doubles.
• 3. According to Boyles Law pressure will
  decrease by half if volume doubles.
• 4. The pressure will double according to the
  Combined Gas Law.

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Day 5 Quiz (Pressure!)