Page 97 - Science Coursebook

7.1 What is a salt?

Questions

1 Think about what you have already learnt about acids.
a What are the properties of acids?
b Name some everyday products that contain acid.
2 Look at the formulae of the compounds in the table on the opposite page.
a What is similar about the formula for hydrochloric acid and that for
sodium chloride?
b What is different about these two formulae?

A+I 3 The illustration below shows a label on a jar of orange preserve.

Allergy advice: No nuts.
Suitable for vegetarians.
Ingredients: Sugar, oranges,
water, concentrated lemon
juice, sodium citrate, citric
acid, bitter orange oil.
Prepared with 30 g of fruit
per 100 g.

a Which ingredient is a salt?

b Use the internet to find out why this ingredient is added to some
kinds of food.

Activity 7.1
Researching a salt

Choose a salt to research. Your teacher will give you some suggestions.

Use the library or the internet to find the answers to these questions:

• How is this salt obtained or made?
• What is the salt used for?
Present what you have found out in an interesting way. You could make a poster,
give a short talk or make a slide show.

Summary

• Salts are compounds that have hundreds of different uses in
everyday life.
• Salts are formed when the hydrogen in an acid is replaced by a
metal or ammonium.

7 Salts 95