Molecular Reactions And Intermolecular Forces

Question 1

How can observable properties be explained?

Answer 1

By considering the nature and strength of intermolecular forces within a covalent molecular substance.

Question 3

Define melting point.

Answer 3

Temperature at which a solid turns into a liquid.

Also the same as the freezing point.

Question 4

Examples of melting points.

Answer 4

Water: 0°C
Oxygen gas: -218°C
Iron: 1538°C

Question 5

Define boiling point.

Answer 5

Temperature at which the vapour pressure of a liquid equals the external pressure causing the liquid to boil and form a gas.

Question 6

Define solubility.

Answer 6

The ability of any substance (called a solute) to dissolve in another substance (called the solvent) to form a solution.

Question 7

Define vapour pressure.

Answer 7

The equilibrium pressure of a vapour above a liquid in a closed container.

Question 8

What is the cause of the pressure of the vapour?

Answer 8

The amount that evaporates.

Question 9

Examples of vapour pressure.

Answer 9

Water: 3kPa (at 25°C)
Ethanol: 8kPa (at 25°C)

Question 10

Define bonding.

Answer 10

Forces of attraction between atoms to form chemical substances.
Also known as Intramolecular forces.

Question 11

What are the three types of bonding?

Answer 11

Ionic
Covalent
Metallic

Question 12

Define intermolecular forces.

Answer 12

Forces of attraction operating between molecules of covalently bonded substances.
Weak compared to the intramolecular forces, the forces which keep a molecule together

Question 13

What is the relative volume of a gas?

Answer 13

Large

Question 14

What is the relative volume of a liquid?

Answer 14

Small

Question 15

What is the relative volume of a solid?

Answer 15

Small

Question 16

What is the dependence of the volume of a gas on volume of container?

Answer 16

Volume of container