Module 6

Question 1

Kinetic Molecular Theory

Answer 1

1) The molecules in a gas are small and very far apart.
2) The molecules are in constant random motion.
3) Molecules collide with each other and with the walls of the container.
4) When collisions occur, kinetic energy is conserved (the collisions are perfectly elastic).
5) The molecules exert no attractive or repulsive forces on one another except during the process of collision. Between collisions, the molecules move in straight lines.
6) The average translational kinetic energy of the molecules is proportional to the Kelvin temperature. Avg Ek = (3/2)RT

Question 2

The Ideal Gas Law

Answer 2

PV=nRT

Question 3

Pressure (P)

Answer 3

Force per unit area.

Question 4

Volume (V)

Answer 4

Provides a measure of the space occupied. In litres.

Question 5

Kelvin Temperature (T)

Answer 5

Provides a measure of the average translational kinetic energy of the molecules in a sample. Avg Ek = (3/2)RT

Question 6

Intermolecular Forces

Answer 6

Attractions between molecules that hold them together.

Question 7

R

Answer 7

Universal gas constant.

Question 8

All Gas Systems at Constant T and P

Answer 8

The volume ratio is equal to the mole ratio.

Question 9

P Total

Answer 9

Ptot = PA + PB + PC

Question 10

Ratio for Partial Pressures

Answer 10

PA = (na/ntot) x Ptot

Question 11

The Ideal Gas Model Neglects

Answer 11

1) The size of the molecules.
2) Intermolecular forces.

Question 12

Real Gas Equation (Van der Waals)

Answer 12

(P + an^2/V^2) x (V - nb) = nRT

Question 13

a

Answer 13

Provides a measure of the strength of the intermolecular forces.

Question 14

b

Answer 14

Provides a measure of the sizes of the molecules.

Question 15

Compressibility Factor (Z)

Answer 15

Tells us how gas samples deviate from ideal behaviour. PV/nRT. Is 1 for an ideal gas.

Question 16

Condensation

Answer 16

Gas to liquid.

Question 17

Vaporization

Answer 17

Liquid to gas. Requires an input of energy.

Question 18

Deposition

Answer 18

Gas to solid.

Question 19

Sublimation

Answer 19

Solid to gas. Requires an input of energy.

Question 20

Fusion

Answer 20

Solid to liquid. Requires an input of energy.

Question 21

Freezing

Answer 21

Liquid to solid.

Question 22

STP

Answer 22

Standard temperature and pressure (0 °C and 100 kPa).

Question 23

SATP

Answer 23

Standard ambient temperature and pressure (25 °C and 100 kPa).

Question 24

Vapour Pressure

Answer 24

Pressure of vapour that forms above a liquid in a closed container.

Question 25

Normal Boiling Point (Tvap)

Answer 25

Temperature at which the vapour pressure of the liquid equals 1 atm (the boiling point at 1 atm).

Question 26

Surface Tension (γ)

Answer 26

Energy required to increase the surface area of a liquid.

Question 27

Viscosity (η)

Answer 27

Provides a measure of a fluid’s resistance to flow.

Question 28

Polarizability (α)

Answer 28

A measure of the extent to which its charge cloud can be distorted (polarized) by another molecule. How squishy is the electron cloud.

Question 29

Intermolecular Forces

Answer 29

Attractive forces between molecules.

Question 30

Dipole Moment (µ)

Answer 30

The permanent uneven distribution of electron density.

Question 31

Dipole-Dipole Forces

Answer 31

When molecules possess a permanent dipole moment.

Question 32

London Dispersion Forces (LDFs)

Answer 32

Present in every molecule. The electron density shifts and changes creating non-permanent dipole moments.

Question 33

Hydrogen Bond

Answer 33

When H is bonded to N, O, or F.