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1. 24/02/11 TELLING THEM APART ACIDS & ALKALIS Chapter One

2. What are Acids? 24/02/11 YOUR TASK Write down all you know about Acids.

5. Strong And Weak Acids 24/02/11 An Acid is classified as strong or weak depending on its ability to dissociate in water. Acids dissociates when the turn from molecule into ions when dissolved in water.

6. Strong Or Weak Acid 24/02/11 A strong Acid dissociates completely in water. E.g Sulphuric Acid or Nitric Acid A weak Acid dissociates partially in water e.g Ethanoic Acid

7. YOUR TASK 24/02/11 Acids have many properties that distinguish them from other substances . Can you write down some of these properties?

10. 24/02/11 How do scientists test for acids and basic solutions? Scientist can test a substance to see whether it is acidic or basic (alkalis) by using an indicator.

11. INDICATORS 24/02/11 What are indicators? Indicators are substances that will change colors when they come in contact with an acid or a base.

12. 24/02/11 Why do we need indicators? Indicators are a safe way to help scientist determine whether a substance is an acid or an alkali.

13. 24/02/11 Remember what we said about acids and alkalis. Often you do not want to come in direct contact with them as they can be harmful.

14. WARNING 24/02/11 Never pour water into a concentrated acid as it heats up and can spit hot acid at you.

15. 24/02/11 ACIDS AND BASES Starter Activity What are Acids and Bases? Name a few examples.

16. FACT 24/02/11 Acids and bases are two important classes of compounds that have different properties from one another.

17. 24/02/11 ACIDS-often give food a sour, sharp flavor (lemon juice) and can be helpful, such as the acids in your stomach. Strong acids can burn your skin. BASES- on the other hand feel bitter and slippery.

18. 24/02/11 The following table shows colour changes and changes range for 4 indicators

22. FACT YOU SHOULD KNOW 24/02/11 The most striking property of both acids and bases is their ability to change the colour of certain vegetable materials.