Year 9 revision and recap 2 Chemistry

Revision and recap

• Acids and bases

• pH scale

• Metals and acids

• Metal carbonates and acids

• metal oxides and acid

• Reactivity of metals

• Endothermic and exothermic reactions

• Combustion reactions

Content covered

Acids and bases

Acids are substances that release Hydrogen ions (H⁺)
Bases are substances that release hydroxide ions (OH^-)

When an acid reacts with a base it neutralises the acid producing a salt and water.

Acid + base -> salt + water

Drag and Drop

Fill in the blanks in the following reaction:

Acid + ​

Placeholder

-> ​

Placeholder

+ water

Drag these tiles and drop them in the correct blank above

base

salt

metal oxide

sodium chloride

hydrogen

carbon dioxide

Drag and Drop

Fill in the blanks in the following reaction:

​

Placeholder

+ ​ Sodium hydroxide -> ​ ​

Placeholder

+ water

Drag these tiles and drop them in the correct blank above

hydrochloric acid

Sodium chloride

metal oxide

hydrogen

carbon dioxide

Match

Match the following acids and bases names with their formula

• Sodium hydroxide

• Hydrochloric acid

• Copper oxide

• Nitric acid

• Sulphuric acid

NaOH

HCl

CuO

HNO₃

H₂SO₄

• NaOH

• HCl

• CuO

• HNO₃

• H₂SO₄

Open Ended

A water sample from a pool was tested using universal indicator. It had a colour change of yellow (pH of 3). What does this tell you about the water sample?

Open Ended

A farmer planted hydrangeas in his garden to identify the pH of the soil. He knows that these flowers become blue if the soil is acidic, purple if the soil is neutral and pink if the soil is basic.

In the garden, the flowers are purple but gradually turn to pink as they continue along towards the house. What does this tell you about the hydrangeas?

Metals and Acids

When metals and acids react with each other, the products form include a salt and hydrogen gas (MASH).

Metal + Acid -> Salt + Hydrogen

Match

Match the following acids to their salts

• Nitric acid

• Hydrochloric acid

• Sulphuric acid

Nitrate

Chloride

Sulphate

• Nitrate

• Chloride

• Sulphate

Open Ended

Write the word equation for the following reaction:

Potassium reacts with nitric acid to produce potassium nitrate and hydrogen gas

Drag and Drop

Drag the correct answer to show the reaction between a metal and acid.

potassium + ​

Placeholder

-> Potassium sulphate + ​

Placeholder

Drag these tiles and drop them in the correct blank above

Sulphuric acid

hydrogen

Water

Carbon dioxide

nitric acid

hydrochloric acid

Drag and Drop

Drag the correct answer to show the reaction between a metal and acid.

Sodium + Hydrochloric acid -> ​

Placeholder

+ Hydrogen

Drag these tiles and drop them in the correct blank above

Sodium chloride

Water

Carbon dioxide

nitric acid

hydrochloric acid

Sodium nitrate

Sodium sulphate

Metal carbonates and acids

When metal carbonates and acids react with other the products form include a salt, carbon dioxide and water.


Metal carbonates + Acid -> Salt + Carbon dioxide + Water

Drag and Drop

Drag the correct answer to show the reaction between a metal carbonate and acid.

Lithium carbonate + Hydrochloric acid -> ​

Placeholder

+ ​ Carbon dioxide + Water

Drag these tiles and drop them in the correct blank above

Lithium chloride

Water

Carbon dioxide

nitric acid

hydrochloric acid

Drag and Drop

Drag the correct answer to show the reaction between a metal carbonate and acid.

​

Placeholder

+ ​

Placeholder

-> ​ Copper sulphate + ​ Carbon dioxide + Water

Drag these tiles and drop them in the correct blank above

Copper carbonate

Sulphuric acid

Water

Carbon dioxide

nitric acid

hydrochloric acid

potassium carbonate

Match

Match the following chemical names to their formulas

• Carbon dioxide

• Potassium carbonate

• Lithium nitrate

• Copper sulphate

• Sodium carbonate

CO₂

K₂CO₃

LiNO₃

CuSO₄

Na₂CO₃

• CO₂

• K₂CO₃

• LiNO₃

• CuSO₄

• Na₂CO₃

Metal oxides and acids

When metal oxides and acids react it produces a salt and water.

Metal oxide + acid -> salt + water

Multiple Choice

True OR False: Metal oxides are classified as bases

• True

• False

Match

Match the following chemical names to their formulas

• Copper oxide

• Sodium hydroxide

• Sodium sulphate

• Hydrogen

• Calcium carbonate

CuO

NaOH

Na₂SO₄

H₂

CaCO₃

• CuO

• NaOH

• Na₂SO₄

• H₂

• CaCO₃

Dropdown

Balance the following equation:

MgO + ​

Select answer

HCl -> MgCl₂ + H₂O

Dropdown

Balance the following equation:

CuO + ​

Select answer

HNO₃ -> Cu(NO₃)₂ + H₂O

Reactivity of metals

Reactivity of metals

Will there be a reaction?

• The MOST reactive metal (or carbon or hydrogen) will ALWAYS be bonded to the non-metal part.

• If the MOST reactive metal (or carbon or hydrogen) is already attached to the non-metal, there will be NO reaction because the less reactive metal is too "weak" to steal the non-metal.

• If the LEAST reactive metal (or carbon or hydrogen) starts attached to the non-metal, there will be a reaction because the more reactive metal is strong enough to steal the non-metal.

Reorder

Reorder the following in relation to most reactive to least reactive metals

• Potassium

• Sodium

• Iron

• Copper

• Gold

1

2

3

4

5

• 1
• 2
• 3
• 4
• 5

Open Ended

Why do you think potassium is the most reactive metal?

Open Ended

Using the reactivity of metals theory and rules, state whether the following reaction will take place and why/why not:

Iron + carbon nitrate -> Iron nitrate + Carbon

Exothermic and Endothermic reactions

Exothermic reactions

A chemical reaction that releases energy.
The reactants have more energy than the products . This energy is released into the surroundings, usually as heat and/or light.

For example: A gas stove uses combustion to release its heat (and light).

Exothermic and Endothermic reactions

Endothermic reactions

A chemical reaction that absorbs energy.
It takes the energy from its surroundings and makes them feel colder.

For example: Sherbet leaves your tongue cold because an endothermic reaction absorbs heat from your mouth.

Multiple Choice

Is the following reaction endothermic or exothermic?

Burning of a candle

• Endothermic

• Exothermic

Multiple Choice

Is the following reaction endothermic or exothermic?

Melting of ice

• Endothermic

• Exothermic

Multiple Choice

Is the following reaction endothermic or exothermic?

Freezing of water to make ice

• Endothermic

• Exothermic

Multiple Choice

Is the following reaction endothermic or exothermic?

Evaporating liquid water

• Endothermic

• Exothermic

Combustion reactions

Complete combustion

Combustion that occurs when there is plenty of oxygen; it produces carbon dioxide and water vapour.

Combustion reactions

Incomplete combustion

Combustion that occurs when oxygen is limited; produces carbon (soot, smoke) and carbon monoxide and does NOT release as much heat or light as complete combustion.

Drag and Drop

Balance the following equation:

C₄H₈ + ​

Placeholder

O₂ -> ​

Placeholder

CO₂ + ​

Placeholder

H₂O

Drag these tiles and drop them in the correct blank above

6

4

5

3

Dropdown

Fill in the blanks of the following word equation:

Magnesium + ​

Select answer

-> Magnesium oxide

Dropdown

Fill in the blanks of the following word equations for incomplete combustion:

Methane + ​

Select answer

-> ​

Select answer

+ Water

​

Select answer

+ Oxygen -> ​Carbon + ​

Select answer

Dropdown

Fill in the blanks of the following word equations for complete combustion:

Ethane + ​

Select answer

-> ​

Select answer

+ water