Lecture 27

Question 1

What occurs in real gases that violate the assumptions made in kinetic molecular theory?

Answer 1

1. Particles in a real gas experience weak interparticle attractions
   - important over short distances
   - occurs between separate atoms or molecules
   - caused by imbalances by e- distribution
2. Particles in a real gas occupy a finite volume
   - at moderately high Pext the Z values are lower than ideal values because of interparticle attractions
   - at very high Pext values are greater than ideal because of particle volume

Question 2

What is the compressibility factor

Answer 2

Z=PV/nRT = PVm/RT

m= molar volume

Question 3

What does the a parameter imply? *

Answer 3

The a parameter describes the interparticle attractions. The larger the a value, the stronger the attraction. Each gas will have a different a parameter based on its attractive forces.

Question 4

What is the b parameter related to ?

Answer 4

Larger b value implies larger molecular size

Question 5

Why are the constants a and b effectively zero according to KMT for ideal gas behaviour

Answer 5

Because the particles do not attract each other and have no volume

Question 6

What does the van der Waal equation become under ordinary conditions (P and T)

Answer 6

The ideal gas law

Question 7

When does the behaviour of an ideal gas deviate from ideality

Answer 7

When attractive forces between gas particles become significant. When these forces are strong enough the gas may condense to a liquid. The LDF that hold particles together are relatively weak compared to covalent bonds.

Question 8

What happens when water undergoes a change in state

Answer 8

The intramolecular forces are intact, but intermolecular forces are distrusted or formed

Question 9

What are intramolecular forces

Answer 9

Forces that exist within a molecule

Question 10

What are intermolecular forces

Answer 10

Forces that exist between the molecule