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Chemical Changes

Physical Change

Chemical Change

No new substances formed

New substances formed

Atoms not rearranged

Atoms rearranged

Reversible using separation techniques

Irreversible

Heat energy taken in or given out

Heat energy taken in or given out

Different Types of Chemical Changes interactions

Mixing

Neutralisation

Heat

Thermal Decomposition

Oxygen

Oxidation

Combustion

Cellular Respiration

Rusting

Browning of Apples

Light

Photosynthesis

X-Ray

Electricity

Electrolysis

Electroplating

Neutralisation

  • Process when an acid reacts with and alkali

  • Salt and Water is formed

  • Eg. Hydrochloric acid(acid) reacts with sodium hydroxide(alkali) to form sodium chloride and water

Thermal Decomposition

  • Process where a substance is broken down into two or more simpler substances when heated

  • Eg. Copper(II) carbonate is heated to form copper(II) oxide and carbon dioxide

Oxidation

  • Process where a substance reacts with oxygen

Browning

  • Exposed surface of apples turn brown due to reaction with oxygen in the air

Combustion

  • Process where a substance reacts with oxygen in the presence of heat, releasing a lot of it in the process

  • One or more new substances produced

  • Eg. Charcoal(carbon) in a barbecue pit burns in oxygen to form carbon dioxide

  • Eg. Combustion of methane gas(natural) to generate electricity in power plants which forms carbon dioxide and water- If combustion is incomplete, produces carbon monoxide, carbon dioxide and water

Cellular Respiration

  • Process where living cells of plants and animals take in oxygen to release the energy stored in glucose

  • To provide cells with energy to grow and reproduce

  • Carbon dioxide and Water are produced

Rusting

  • Process where iron reacts with oxygen in the presence of water vapour

Photosynthesis

  • Process where green plants make food in the presence of light

Electrolysis

  • Chemical decomposition of substances with the passage of an electric current

Electroplating

  • Process where a substance is coated with a metal with the passage of an electric current

Acids and Alkalis

  • Acids- substance that dissolves in water and dissociates (break up) to give hydrogen ions (h+) which is responsible for the properties of an acid

  • Alkali- substance that dissolves in water and dissociates (break up) to give hydroxide ions (OH-) which is responsible for the properties of an alkali

Acid

Alkali

pH value less than 7

pH value of more than 7

tastes sour

tastes bitter and feels slippery

turns blue litmus paper red

turns red litmus paper blue

no effect on red litmus paper

no effect on blue litmus paper

turns universal indicator solution to (orange) or red (red)

turns universal indicator solution to blue (weak) or purple (strong)

corrosive if concentrated

corrosive if concentrated

conducts electricity when dissolved in water due to free moving hydrogen ions

conducts electricity when dissolved in water due to free moving hydroxide ions

pH scale

0-3

Strong acid

4-6

weak acid

7

neutral

8-10

weak alkali

11-14

strong alkali

C H O M

Acids react with…

Carbonates

Hydroxides and Oxides

Metals

Forms?

Salt, Carbon dioxide gas and water

Salt and Water

Salt and Hydrogen Gas

Example

Calcium Carbonate reacts with hydrochloric acid to form calcium chloride, water and carbon dioxide

Sodium Hydroxide and nitric acid reacts to form sodium nitrate and water

Example

Potassium Carbonate reacts with sulfuric acid to form potassium sulfate, water and carbon dioxide

Sodium Oxide and nitric acid reacts to form sodium nitrate and water

How to test for it

Bubble the gas through limewater (calcium hydroxide) in which a white precipitate will form

Insert a lighted splint into the test tube of hydrogen gas in which the lighted splint will extinguish with a ‘pop’ sound

2E

Chemical Changes

Physical Change

Chemical Change

No new substances formed

New substances formed

Atoms not rearranged

Atoms rearranged

Reversible using separation techniques

Irreversible

Heat energy taken in or given out

Heat energy taken in or given out

Different Types of Chemical Changes interactions

Mixing

Neutralisation

Heat

Thermal Decomposition

Oxygen

Oxidation

Combustion

Cellular Respiration

Rusting

Browning of Apples

Light

Photosynthesis

X-Ray

Electricity

Electrolysis

Electroplating

Neutralisation

  • Process when an acid reacts with and alkali

  • Salt and Water is formed

  • Eg. Hydrochloric acid(acid) reacts with sodium hydroxide(alkali) to form sodium chloride and water

Thermal Decomposition

  • Process where a substance is broken down into two or more simpler substances when heated

  • Eg. Copper(II) carbonate is heated to form copper(II) oxide and carbon dioxide

Oxidation

  • Process where a substance reacts with oxygen

Browning

  • Exposed surface of apples turn brown due to reaction with oxygen in the air

Combustion

  • Process where a substance reacts with oxygen in the presence of heat, releasing a lot of it in the process

  • One or more new substances produced

  • Eg. Charcoal(carbon) in a barbecue pit burns in oxygen to form carbon dioxide

  • Eg. Combustion of methane gas(natural) to generate electricity in power plants which forms carbon dioxide and water- If combustion is incomplete, produces carbon monoxide, carbon dioxide and water

Cellular Respiration

  • Process where living cells of plants and animals take in oxygen to release the energy stored in glucose

  • To provide cells with energy to grow and reproduce

  • Carbon dioxide and Water are produced

Rusting

  • Process where iron reacts with oxygen in the presence of water vapour

Photosynthesis

  • Process where green plants make food in the presence of light

Electrolysis

  • Chemical decomposition of substances with the passage of an electric current

Electroplating

  • Process where a substance is coated with a metal with the passage of an electric current

Acids and Alkalis

  • Acids- substance that dissolves in water and dissociates (break up) to give hydrogen ions (h+) which is responsible for the properties of an acid

  • Alkali- substance that dissolves in water and dissociates (break up) to give hydroxide ions (OH-) which is responsible for the properties of an alkali

Acid

Alkali

pH value less than 7

pH value of more than 7

tastes sour

tastes bitter and feels slippery

turns blue litmus paper red

turns red litmus paper blue

no effect on red litmus paper

no effect on blue litmus paper

turns universal indicator solution to (orange) or red (red)

turns universal indicator solution to blue (weak) or purple (strong)

corrosive if concentrated

corrosive if concentrated

conducts electricity when dissolved in water due to free moving hydrogen ions

conducts electricity when dissolved in water due to free moving hydroxide ions

pH scale

0-3

Strong acid

4-6

weak acid

7

neutral

8-10

weak alkali

11-14

strong alkali

C H O M

Acids react with…

Carbonates

Hydroxides and Oxides

Metals

Forms?

Salt, Carbon dioxide gas and water

Salt and Water

Salt and Hydrogen Gas

Example

Calcium Carbonate reacts with hydrochloric acid to form calcium chloride, water and carbon dioxide

Sodium Hydroxide and nitric acid reacts to form sodium nitrate and water

Example

Potassium Carbonate reacts with sulfuric acid to form potassium sulfate, water and carbon dioxide

Sodium Oxide and nitric acid reacts to form sodium nitrate and water

How to test for it

Bubble the gas through limewater (calcium hydroxide) in which a white precipitate will form

Insert a lighted splint into the test tube of hydrogen gas in which the lighted splint will extinguish with a ‘pop’ sound