Module 3: Reactive Chemistry

Question 1

What is a chemical change?

Answer 1

When a new substance is formed and bonds are broken and formed

Question 2

What is a physical change?

Answer 2

When there is a change in property but no new products are formed

Question 3

What are four signs of chemical change?

Answer 3

• Colour change
• Significant temperature change
• Formation of precipitate in a solution
• Production of gas/bubbles

Question 4

What does conservation of atoms mean?

Answer 4

No atoms are created or destroyed, therefore mass of products must equal mass of reactants

Question 5

What is a synthesis reaction?

Answer 5

Involves forming a compound from elements or from other, usually smaller compounds

Question 6

What is a decomposition reaction?

Answer 6

Is a reaction in which one reactant is broken down into two or more products

Question 7

What is thermal decomposition?

Answer 7

When heat is used for decomposition reactions

Question 8

What is electrolysis?

Answer 8

When electricity is used for decomposition reactions

Question 9

What is photolysis?

Answer 9

When light energy is used for decomposition reactions

Question 10

What is a combustion reaction?

Answer 10

It is the combustion of a hydrocarbon and is an oxidation and exothermic reaction

Question 11

What are the three key elements of combustion?

Answer 11

1. Fuel
2. Oxygene
3. Energy

Question 12

What is complete combustion?

Answer 12

Combustion which occurs when there is plenty of oxygen

Question 13

What is produced in complete combustion?

Answer 13

carbon dioxide and water

Question 14

What is incomplete combustion?

Answer 14

Combustion which occurs when there is limited oxygen

Question 15

What is produced in incomplete combustion?

Answer 15

carbon monoxide + water
carbon (solid) + water
carbon monoxide + carbon (solid) + water

Question 16

What is a precipitation reaction?

Answer 16

When an insoluble compound is formed when two clear solutions are mixed

Question 17

What is a precipitate?

Answer 17

The solid formed in a precipitation reaction

Question 18

What are spectator ions?

Answer 18

Ions which are not used to form the precipitate and will start aqueous and remain aqueous

Question 19

What is an ionic equation?

Answer 19

A chemical equation which does not include spectator ions

Question 20

What does SNAAP stand for?

Answer 20

Sodium
Nitrate
Ammoniam
Acetate
Potassium

Question 21

What is the equation for acid and base reactions?

Answer 21

Acid + Base –> Salt + Water

Question 22

What is the equation for acid and carbonate reactions?

Answer 22

Acid + Metal Carbonate –> Salt + Carbon Dioxide + Water

Question 23

What is the equation for acid and metal reastions?

Answer 23

Acid + Metal –> Salt + Hydrogen Gas

Question 24

What food did indigenous people detoxifying using chemical reactions?

Answer 24

Cycad fruit

Question 25

What were the two ways cycads were detoxified?

Answer 25

Leaching - soaking poisons out Fermentation - leaving the fruit in a moist environment for months

Question 26

What happens when metal reacts with oxygen?

Answer 26

An electron is transferred from metal atoms to oxygen atoms

Question 27

What is the formula for the reaction between oxygen and metal?

Answer 27

metal + oxygen --> metal oxide

Question 28

What happens when metal reacts with water?

Answer 28

Some metals displace hydrogen and hydroxide or metal oxide

Question 29

When is metal oxide formed when water reacts with metal?

Answer 29

When the metal has a low reactivity such as aluminium zinc or iron and only reacts with steam

Question 30

When will a reaction between metals and other metallic ions occur?

Answer 30

When the solid metal is more reactive than the metal ions in the solution

Question 31

Methane

Answer 31

CH4

Question 32

Ethanol

Answer 32

C2H5OH