» Unit 2 – Pressure explore. more.

LEARNING OBJECTIVES

Recognize that the model of matter that we use during this unit is essentially that proposed by Democritus.
Relate observations of diffusion to particle motion and collision in both liquid and gas phases.
Relate observations regarding the addition of energy by warming to increased particle motion.
Explain, at the particle level, how a thermometer measures the temperature of the system.
Explain the basis for the Celsius temperature scale.
State the basic tenets of Kinetic Molecular Theory (KMT) as they relate to gases. Particles of a gas:
- are in constant motion, moving in straight lines until they collide with another particle or a wall of the container in which they are enclosed.
- experience elastic collisions; i.e., they do not eventually “run down”
- do not stick to other particles.
The speed of the particles is related to their temperature.
The pressure of a gas is related to the frequency and impact of the collisions of the gas particles with the sides of the container in which they are enclosed.
The 3 variables P, V and T are interrelated. Any factor that affects the number of collisions has an effect on the pressure. You should be able to:
- Predict the effect of changing P, V or T on any of the other variables.
- Explain (in terms of the collisions of particles) why the change has the effect you predicted.
- Explain the basis for the Kelvin scale. Keep in mind that one must use the absolute temperature scale to solve gas problems.
- Use factors to calculate the new P, V or T. Make a decision as to how the change affects the variable you are looking for.