Y7 Chemical Reactions and Limestone

Topic 3

What is a fuel?

A material that burns to transfer useful energy.

What is combustion?

A chemical reaction in which a substance reacts quickly with oxygen and gives out heat and light.

What is oxidation?

A chemical reaction in which substances react with oxygen to form oxides.

What are the products of combustion?

Carbon dioxide and water.

What is a decomposition reaction?

A chemical reaction in which a compound breaks down to form simpler compounds and/or elements.

What is thermal decomposition?

A chemical reaction where a compound breaks down when heated.

What is the clue to look for to tell if a decomposition reaction is taking place?

There will be one reactant and many products.

What is the chemical formula for limestone?

CaCO3.

What is the chemical formula for calcium oxide?

CaO.

What is the chemical formula for calcium hydroxide?

Ca(OH)2.

How do you turn calcium carbonate into calcium oxide?

Heat it strongly.

How do you turn calcium oxide into calcium hydroxide?

Add water.

How do you turn calcium hydroxide into calcium carbonate?

Bubble carbon dioxide through it.

What is the word equation for the thermal decomposition of calcium carbonate?

Calcium carbonate → Calcium oxide + carbon dioxide.

what is an endothermic reaction?

A reaction that takes in heat (it gets colder/the temperature goes down)

what is an exothermic reaction?

A reaction that gives out heat (it gets warmer/the temperature goes up)

 What is the law of conservation of mass?

In a chemical reaction the mass of the reactants is always equal to the mass of the products