3.1 Introduction

Question 1

What happens when a physical change occurs?

Answer 1

• Creates no new substances
• Are usually easy to reverse
• Absorb/ release small amounts of energy

Question 2

What happens when chemical change occurs?

Answer 2

• Creates a new substance
• Are usually difficult to reverse
• Absorb/ release large amounts of energy

Question 3

Example of a physical change?

Answer 3

Ice melting

Question 4

Why is ice melting a physical change?

Answer 4

• Particles are still water particles
• Reversed by putting in freezer
• Surroundings does not get much hotter or colder

Question 5

Example of a chemical change?

Answer 5

Burning wood

Question 6

Why is burning wood a chemical change?

Answer 6

• Wood particles and oxygen particles turn into soot
• Impossible to collect soot and turn back to wood (irreversible)
• Surroundings get very hot

Question 7

What is the chemical test for water?

Answer 7

Anhydrous Copper (II) Sulphate: Turns from white —–> Blue

Question 8

What is the physical test for water?

Answer 8

Melting point: 0°C
Boiling point: 100°C

Question 9

What are metal properties?

Answer 9

• High MP/BP
• Electrical conductors
• Malleable
• Shiny

Question 10

What are non-metal properties?

Answer 10

• Low MP/BP
• Electrical insulators
• Brittle
• Dull

Question 11

What are the diatomic molecules?

Answer 11

H2, N2, O2, F2, Cl2, Br2, I2, At2
(Remembered as Hydrogen 7)

Question 12

Define a compound?

Answer 12

A substance containing one type of atom, chemically bonded together

Question 13

What type of bonding is metallic?

Answer 13

Metal + Metal

Question 14

What type of bonding is ionic?

Answer 14

Metal + Non-metal

Question 15

What type of bonding is covalent?

Answer 15

Non-metal + Non-metal

Question 16

Define solute?

Answer 16

The substance which is going to be dissolved

Question 17

Define solvent?

Answer 17

The liquid doing the dissolving

Question 18

Define solution?

Answer 18

The resulting mixture of solute dissolved in solvent

Question 19

Define saturated?

Answer 19

A solution in which no more solute can be dissolved

Question 20

Define suspension?

Answer 20

A solid floating in a liquid because it cannot be dissolved

Question 21

Define soluble?

Answer 21

A substance which can be dissolved

Question 22

Define insoluble?

Answer 22

A substance which cannot be dissolved

Question 23

How is solubility measured?

Answer 23

g per 100cm3 of solvent

Question 24

Define an element?

Answer 24

A substance containing only one type of atom

Question 25

How are compounds formed?

Answer 25

Often by heating elements together

Question 26

What does metal + metal =?

Answer 26

Metallic bonding

Question 27

What does metal + non-metal =?

Answer 27

Ionic bonding

Question 28

What does non-metal +non-metal =?

Answer 28

Covalent bonding

Question 29

What does making ammonium chloride in a tube illustrate?

Answer 29

Diffusion of gases