Acids and Bases

Acids and bases are two different substances commonly involved in chemical reactions. Complete the following activities using p262-265 of your text book. Ensure you read the appropriate section before beginning the question.

1.State whether the following pictures describe acids, bases or both.

2.List common acids & bases that you may find in these areas of your home or at school and what they are used for. One example has been done for you.

Name of Acid Use in this area Name of base Use in this areaKitchen

Outdoors (e.g. garden, garage)

Bathroom

Science Laboratory

Hydrochloric acid ExperimentsManufacture of other chemicals

3. Explain the relationship between a base and an alkali.______________________________________________________________________________________________________________________________________________________________________________________

4. What is an indicator?____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

5. Name two commonly used indicators & their effects on acids & bases.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

The pH Scale

6. Explain what the pH scale is and what it tells us.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

7. Explain how the pH of a substance can be determined.____________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

8. Create your own pH scale by following the instructions below. Make it attractive so it can be displayed - Collect an A3 piece of paper and strips of coloured paper from your teacher.- Stick the coloured paper in the correct order on the A3 sheet- Label your pH scale with numbers- Label your pH scale to show the colours that indicate an acid, a base or a neutral solution. (Remember to

state whether the acid/base is strong or weak).- Draw pictures to indicate where different substances fit on the pH scale- WRITE YOUR NAME!

Everyday Examples of Acids & Bases

9. Explain how the following pictures related to acids & bases. One example has been completed for you.

Picture Explanation

Bee, car battery & lemons

Toilettries – soap, shampoo, toothpaste

Growth of plants

Some plants grow better in acidic soils & some better in basic soils.

If too acidic – add lime.

If too acidic – add ammonium sulfate.

The stomach

Vinegar

Baking Soda

Swimming Pool

Tooth Decay

Neutralisation Neutralisation is a specific type of chemical reaction.

10. What does the word neutralise mean?______________________________________________________________________________________________________________________________________________________________________________________

11. How can we neutralise an acid?___________________________________________________________________________________________

12. How can we neutralise a base?___________________________________________________________________________________________

13. Explain the importance of neutralisation in the following situations and how the acid or base would be neutralised:

a. Wasp sting_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

b. Indigestion_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

c. Growth of plants_______________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________________

14. The reactants of a neutralisation reaction are always:_________________________

15. The products of a neutralisation are always: _________________________________

16. Sometimes the products of a neutralisation reaction may include:_________________

Acids and Metals

17. When an acid reacts with a metal the products are always:______________________

18. Give an example of an acid reacting with a metal (in the form of a word equation)

____________________________________________________________________