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Formulae and equations for SQA National 5 Chemistry

Formulae and equations

This page covers the following topics:

1. Balancing equations

A balanced equation is a model of a chemical reaction that shows the formulae of the reactants and the products. In order for an equation to be balanced, the number of atoms must be equal on both sides of the equation.

Balancing equations

1

Ethane reacts with oxygen to produce carbon dioxide and water. Write the balanced equation for this reaction.

2Cโ‚‚Hโ‚† + 7Oโ‚‚ โ†’ 4COโ‚‚ + 6Hโ‚‚O

Ethane reacts with oxygen to produce carbon dioxide and water. Write the balanced equation for this reaction.

2

Sodium chloride, also known as table salt, is formed by a reaction of sodium and chlorine. Write a balanced equation for this reaction.

2Na + Clโ‚‚ โ†’ 2NaCl

Sodium chloride, also known as table salt, is formed by a reaction of sodium and chlorine. Write a balanced equation for this reaction.

3

The reaction of iron(III) oxide and hydrogen results in the formation of iron and water. What is the balanced equation for this reaction?

Feโ‚‚Oโ‚ƒ + 3Hโ‚‚ โ†’ 2Fe + 3Hโ‚‚O

The reaction of iron(III) oxide and hydrogen results in the formation of iron and water. What is the balanced equation for this reaction?

4

Balance the equation Zn + HCl โ†’ ZnClโ‚‚ + Hโ‚‚.

Zn + 2HCl โ†’ ZnClโ‚‚ + Hโ‚‚

Balance the equation Zn + HCl โ†’ ZnClโ‚‚ + Hโ‚‚.

5

Balance the equation Sโ‚ˆ + Fโ‚‚ โ†’ SFโ‚†.

Sโ‚ˆ + 24Fโ‚‚ โ†’ 8SFโ‚†

Balance the equation Sโ‚ˆ + Fโ‚‚ โ†’ SFโ‚†.

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