Starter: in pairs brainstorm as many different TYPES of reaction as you know

Types of Chemical Reaction

Neutralisation

This is the type of reaction that occurs when an ACID is mixed with an ALKALI to produce a NEUTRAL solution.

ACID + ALKALI SALT + WATER

Can you think of 3 examples of neutralisation reactions?

Extension – when can knowing about neutralisation reactions be useful?

Neutralisation

A use of neutralisation is in the treatment of indigestion. The acid in the stomach is hydrochloric acid (HCl)

Hydrochloric + Magnesium Magnesium + Water Acid Carbonate Chloride HCl + MgCO3 MgCl2 + H2O

Word Equation

Symbol Equation

What do these large numbers stand for?

Measuring the strength of an acid or alkali

Not all acids/alkalis are the same strength, so we use the pH scale to explain it

A neutral pH means there is no acid or alkali present. Neutral pH is 7.

Adding an alkali to an acid brings its pH closer to 7.

A neutral pH means there is no acid or alkali present. Neutral pH is 7.

Adding an acid to an alkali brings its pH closer to 7.

You have 3 antacids, their pHs are:• Antacid A – pH 9• Antacid B – pH 13• Antacid C – pH 10.5

Which of these will be better at neutralising the Hydrochloric Acid if you have to use the same amount of each?

The extremes of the pH scale are very harmful to human beings. Which antacids do you think you should rule out using because of this?

You have 3 antacids, the mass required to fully neutralise stomach acid is:• Antacid A – 84g• Antacid B – 50g• Antacid C – 70g

The cost per 100g is:• Antacid A – 67p• Antacid B – 98p• Antacid C – 59p

Which of these is the most cost effective?What factors will affect the RRP of the antacid?

Oxidation

This is the type of reaction that occurs when a metal is combined with oxygen to form a metal oxide.

METAL + OXYGEN METAL OXIDE

What is the most common type of oxidation reaction?

Oxidation

Oxidation is the process behind the rusting of iron. It weakens nails, bikes and other metal objects as the metal oxide is not as strong

Iron + Oxygen Iron Oxide

2Fe + 3O2 2Fe2O3

What do these large numbers stand for?

Combustion

This is the type of reaction that occurs when a fuel is combined with oxygen to produce water and carbon dioxide releasing energy

FUEL + OXYGEN CARBON + WATER

DIOXIDEWhat do we use combustion reactions for?

Extension – what biological combustion reaction have we studied?

Combustion

Combustion is used to power cars, buses, aeroplanes etc. The fuel is petrol, whose chemical name is octane

Octane + Oxygen Carbon + Water

Dioxide C8H18 + O2 CO2 + H2OIs there the same amount of each element on either side of the arrow?

Combustion

When we write symbol equations we have to make sure that they are BALANCED i.e. That there is the same number of each element on either side of the arrow.

C8H18 + O2 CO2 + H2O 2C8H18 + 27O2 16CO2 + 18H2ODon’t panic!I will show you how to balance equations next week.

Decomposition

This is the type of reaction that occurs when an large compound is broken down into smaller compounds

Compound 1 Compound 2 + Compound 3

Can you think of any examples of decomposition reactions?

Decomposition

An example of decomposition is the fermentation of glucose to form ethanol and carbon dioxide

Glucose Ethanol + Carbon Dioxide

When is this reaction used?

C6H12O6 2C2H5OH + 2CO2

Word Equation

Symbol Equation

Thermal Decomposition

An example of thermal decomposition is the breakdown of calcium carbonate into calcium oxide and carbon dioxide

Calcium Carbonate Calcium + Carbon Oxide DioxideTry to write the symbol equation using the periodic table to help

CaCO3 CaO + CO2

Displacement

This is the type of reaction that occurs when a more reactive element takes the place of a less reactive one in a compound

Compound + Element Compound + Element 1 2 2 1Can you think of any examples of displacement reactions?

Copper + Zinc Zinc + Copper Sulphate Sulphate

Displacement

An example of displacement is the decolourisation of copper sulphate (blue) by zinc Word

Equation

Try to write the symbol equation using the periodic table to help. The symbol for sulphate is SO4

CuSO4 + Zn ZnSO4 + Cu

Metals and Acid

This is the type of reaction that occurs when a metal reacts with an acid to form a salt and hydrogen gas

METAL + ACID SALT + HYDROGEN

What is a test for hydrogen gas?

Metals and Acid

An example of this type of reaction occurs when magnesium is placed in sulphuric acid

Magnesium + Sulphuric Magnesium + Hydrogen Acid SulphateTry to write the symbol equation using the periodic table to help. The symbol for sulphate is SO4

Mg + H2SO4 MgSO4 + H2