Combustion & Corrosion

Question 1

Endothermic reactions

Answer 1

• a chemical reaction that absorbs energy: eg when a cold pack is applied on an injury, absorbing the energy
• in an endothermic reaction the products have more energy than the reactants.

Question 2

Exothermic reaction

Answer 2

• a chemical reaction the releases energy: eg a gas stove which has a blue flame releasing the energy in heat or, a series of bush fires as it releases huge amounts of heat and light.
• in an exothermic reaction the reactants have more energy than the products.

Question 3

Reactants.

Answer 3

Substances/chemicals that take part in a chemical reaction

Question 4

Products

Answer 4

Are substances/chemicals that are formed by the chemical reaction

Question 5

Photosynthesis

Answer 5

• a reaction the green plants use to form glucose (sugar)

- this reaction absorbs energy from sunlight, endothermic reaction

Question 6

Combustion reactions

Answer 6

• are examples of exothermic reactions

- oxygen gas is required for combustion to occur. Meaning combustion occurs when something reacts with oxygen

Question 7

Incomplete combustion

Answer 7

• occurs when oxygen is restricted and other reactions occur
• these are known as dirty as they produce carbon which is left behind as soot, charcoal or smoke. They also produce the poisonous gas carbon monoxide (fire produces these substances)

Question 8

Complete combustion

Answer 8

• complete combustion is when oxygen is not restricted and produces carbon dioxide and carbon dioxide which are know as clean reactions

Question 9

Corrosion

Answer 9

The breakdown of metals due to their reaction with other chemicals to form other compounds. An example would be rust

Question 10

Rust

Answer 10

When iron or steel slowly reacts with water and oxygen and corrodes into rust aka hydrated iron oxide

Question 11

Verdigris

Answer 11

A green coating of cooper hydroxide that is produced when copper reacts with moisture, carbon dioxide and oxygen in the atmosphere

Question 12

Tarnish

Answer 12

A black coating of silver sulfate that is produced when silver reacts Sulfur in the atmosphere

Question 13

How is verdigris formed

Answer 13

When copper corrodes by reacting with gases in the air

Question 14

How is tarnished formed

Answer 14

When pure silver reacts with Sulfur creates black coating

Question 15

What is flaky and easy to dislodge

Answer 15

Rust

Question 16

What is aluminium oxide

Answer 16

Is a fine layer of dull grey which appears on the surface of metals when aluminium reacts with the air

Question 17

Anodising

Answer 17

A way of protecting aluminium from corrosion, by deliberately creating a layer of aluminium oxide over it

Question 18

Hydrocarbons

Answer 18

Highly combustible chemicals for example petrol

Question 19

Law of conservation of mass

Answer 19

When atoms are not created or destroyed in a chemical reaction as they can only be rearranged

Question 20

Safety flame

Answer 20

Incomplete combustion as it received no oxygen gas

Question 21

Blue flame

Answer 21

Complete combustion as it receives oxygen gas

Question 22

Examples on endothermic reactions

Answer 22

• photosynthesis
• sherbet tingles in your mouth
• a chemical cold pack as it cools sore muscles

Question 23

Examples of exothermic reactions

Answer 23

• a series of bushfires
• aerobic respiration releases energy for use in cells
• magnesium burns in oxygen releasing light

Question 24

Similarities of exothermic and endothermic reactions?

Answer 24

• they both the form of heat as their energy
• they are both a type of chemical reaction
• they both need two substances to combine to make the certain reaction

Question 25

Differences of exothermic and endothermic reactions

Answer 25

• exothermic reaction lets of energy whereas endothermic absorbs energy

Question 26

Combustion of fossil fuels examples

What the produce and products

Answer 26

• buses burners
• gas stoves
• water heaters
  Produce a hot blue flame by burning methane or ethane gas in oxygen which produce hydrocarbons

Question 27

Indications of incomplete combustion

Answer 27

Carbon in the atmosphere as soot charcoal and smoke

Carbon monoxide poisonous gas

Question 28

Explain respiration

Answer 28

It gives you energy. The reaction needs glucose from food and oxygen from your body. You breathe out its product carbon dioxide

Exothermic reaction

Question 29

Combustion reaction that do not produce carbon dioxide and water

Answer 29

When magnesium and oxygen react they form magnesium oxide

Question 30

Examples of oxidation

Answer 30

Corrosion

Question 31

Similarities of corrosion and rust ion

Answer 31

• both involve the elements of metal in the reactions

Question 32

Difference of corrosion and rusting

Answer 32

• rusting is a type of corrosion

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