1. Acids and Bases

2. Examples of Acids Acids can be found in your foods.
Citric acid – oranges, lemons, limes
Ethanoic acid – vinegar, tomato juice
Tartaric acid – grapes
Tannic acid – tea
Lactic acid – sour milk, yoghurt

3. Acids and Bases in Our Daily Lives
YUM, acid!
They are all around us and are involved in many chemical processes.

4. Examples of Acids Other examples of acids:
Methanoic acid – insect bites, e.g. bee stings, ant bites
Hydrochloric acid – produced in your stomach
Lactic acid – produced in body during power exercises

5. Examples of Acids Lead-acid battery Toilet bowl cleaner
Do-it-yourself cleaners
Make a cleaner out of vinegar, baking soda and lemon juice!

6. Laboratory Acids Hydrochloric acid, HCl Sulphuric acid, H2SO4
Nitric acid, HNO3

7. Types of Acids
Many naturally-occuring acids, e.g. citric acid in oranges, are sometimes known as organic acids.
The other group of acids is called the mineral acids. Most of these are man-made, e.g. sulphuric acid.

8. What is an acid?
A substance which produces hydrogen ions, H+, when it is dissolved in water
All acids produce hydrogen ions, H+, in aqueous solution.
All acids contain hydrogen ions.
BUT, not all compounds containing hydrogen are acids.

9. Properties of Acids Acids have a sour taste. Acids are hazardous.
The word ‘acid’ comes from a latin word ‘acidus’, which means sour.
Acids are hazardous.
Irritants
Acids change the colour of indicators.
Acids turn blue litmus red – a simple test for acid.
Acids dissolve in water to form solutions that conduct electricity.

10. Chemical Reactions of Acids (1)
Acids react with reactive metals to form hydrogen and a salt.
Test for the presence of hydrogen
A burning splint is brought near the mouth of the test tube.
If hydrogen is present, it burns with a ‘pop’ sound.

11. Chemical Reactions of Acids (2)
Acids react with carbonates and hydrogencarbonates to produce carbon dioxide gas
Test for the presence of carbon dioxide
The gas is bubbled through limewater.
If carbon dioxide is present, a white precipitate is formed.

12. Chemical Reactions of Acids (3)
React with metal oxides and hydroxides to from a salt and water.
Neutralisation reaction

13. Storage of Acidic Foods
Acids are stored in glass, plastic jars or clay pots.
Acidic foods are not usually stored in metal containers because metals can react with acids.

14. Do you know? Acid Bath Murder

15. So, what have you learnt today?
Examples of acids
Definition of an acid
Properties of acids
Acids have a sour taste.
Acids are hazardous.
Acids change the colour of indicators.
Acids dissolve in water to form solutions that conduct electricity.
Chemical reactions of acids
Test for gases: Hydrogen and carbon dioxide