10D - Kinetic Molecular Theory

Question 1

Theory: What are the 6 postulates of the theory?

Answer 1

1. Gases can be modelled as as a collection of molecules
2. Gas molecules are in continuous, random motion
3. Volume of gas&raquo_space; volume of molecules
4. Average kinetic energy is proportional to temperature
5. Average kinetic energy does not depend on chemical identity
6. Collisions are elastic and Intermolecular forces are negligible

Question 2

Theory: How does Boyle’s Law affect gas behavior?

Answer 2

P1V1 is constant. If P goes up and V goes down, col freq increases.

Question 3

Theory: How does Avogadro’s Law affect gas behavior?

Answer 3

V1/n1 is constant.
n goes up, V goes up, constant number of collisions.

Question 4

Theory: How does Amonton’s Law affect gas behavior?

Answer 4

P1/T1 constant.
T goes up, P goes up, increased freq and force of col.

Question 5

Theory: Why does the molecular speed distribution and average speed remain constant in a gas sample?

Answer 5

Because there are an enormous amount of gas particles in the sample.

Question 6

Def: What is a Maxwell-Boltzmann distribution?

Answer 6

A molecular speed distribution versus the number/fraction of molecules.

Question 7

Theory: What is the relationship between temperature and KE of a gas sample? How does this affect the M-B distribution.

Answer 7

Proportional. If both increase, the graph is shifted right and flattens. If both decrease, the graph is shifted less steepens.

Question 8

Theory: At a given temperature, all gases have the ____ average KE. What happens if mass changes?

Answer 8

Same. Since in KE = mv^2/2, if m goes up, V goes down.

Question 9

Theory: What is true of M-B dist for gases composed of lighter particles? Why?

Answer 9

They will peak at higher velocities. Lighter particles move faster on average than heavier ones.