Kinetic Molecular Theory of Matter
Chapter 10: Physical Characteristics of Gases
Section 10-1
The Kinetic-Molecular Theory of Matter
Prerequisites
The kinetic-molecular theory is based on the idea that particles of matter are always in motion. The theory can be used to explain the properties of solids, liquids, and gases in terms of the energy of particles and the forces that act between them. ideal gas: an imaginary gas that perfectly fits all the assumption of the kinetic-molecular theory.
Kinetic-Molecular Theory of Gases
(based on the following 5 assumptions)
Most of the volume occupied by a gas is empty space accounts for the lower density of gases compared with that of liquids or solids and explains the fact that gases are easily compressed.
No kinetic energy is lost when particles collide with each other or the walls of the container (elastic collision).
KE is transferred between two particles during collisions; however, the total KE of the two particles remains the same as long as temperature is constant.
Gas particles are in constant or random motion and therefore possess KE, which is energy of motion.
KE of the particles overcomes the attractive forces between them, except near the temperature at which the gas condenses and becomes a liquid.
Gases do not attract or repel each other.
When gas particles collide, they do not stick together but immediately bounce apart.
All gas particles have the same kinetic energy at a given temperature.
All gases at the same temperature have the same average kinetic energy.
Therefore, at the same temperature, lighter gas particles, such as hydrogen molecules, have higher average speeds than do heavier gas particles, such as oxygen molecules.
Properties of Gases
Expansion
Since gases do not have a definite shape or volume, they completely fill any container in which they are enclosed, and they take its shape.
The kinetic-molecular theory explains this because gas particles move rapidly in all directions (Assumption 3)
Section 10-1
The Kinetic-Molecular Theory of Matter
Prerequisites
The kinetic-molecular theory is based on the idea that particles of matter are always in motion. The theory can be used to explain the properties of solids, liquids, and gases in terms of the energy of particles and the forces that act between them. ideal gas: an imaginary gas that perfectly fits all the assumption of the kinetic-molecular theory.
Kinetic-Molecular Theory of Gases
(based on the following 5 assumptions)
Most of the volume occupied by a gas is empty space accounts for the lower density of gases compared with that of liquids or solids and explains the fact that gases are easily compressed.
No kinetic energy is lost when particles collide with each other or the walls of the container (elastic collision).
KE is transferred between two particles during collisions; however, the total KE of the two particles remains the same as long as temperature is constant.
Gas particles are in constant or random motion and therefore possess KE, which is energy of motion.
KE of the particles overcomes the attractive forces between them, except near the temperature at which the gas condenses and becomes a liquid.
Gases do not attract or repel each other.
When gas particles collide, they do not stick together but immediately bounce apart.
All gas particles have the same kinetic energy at a given temperature.
All gases at the same temperature have the same average kinetic energy.
Therefore, at the same temperature, lighter gas particles, such as hydrogen molecules, have higher average speeds than do heavier gas particles, such as oxygen molecules.
Properties of Gases
Expansion
Since gases do not have a definite shape or volume, they completely fill any container in which they are enclosed, and they take its shape.
The kinetic-molecular theory explains this because gas particles move rapidly in all directions (Assumption 3)