pH

What is the pH scale, and why do we need an understanding of pH in everyday life?

1. Learning Goals: To understand what pH is To understand what the colours and numbers on the pH scale mean To understand the pH of some household examples pH SCALE

2. Name an acid What element is common to all acids Name a base What makes a base different from an acid? 4 QUESTIONS

3. WHY DO WE NEED pH?

4. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Neutral pH SCALE Equal H+ and OH-

5. H+ Cl Cl H+ H+ Cl Hydrochloric Acid All acids contain ( H + ) in solution. WHAT IS pH? pH is a fancy measure of the number of H+ ions in solution (but backward) What will sort of number will an acid with lots of H+ give us?

6. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Strong acid Weak acid pH SCALE Lots of H+ Less of H+ The more H+ the solution has, the smaller the pH number

7. OH- Na Na Na OH- OH+ Bases don’t contain H+. Sodium Hydroxide BASES The more OH- is in the base, the less space there is for H+ in solution A weak base contains few OH-… what will that mean about the pH?

8. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Weak base Strong base pH SCALE Very Little H+ Less of H+ The more OH+ the solution has, the less H-, The bigger the pH number is

9. pH SCALE

10. pH Quiz rules: 2 teams (either girls Vs boys or sides of the room First side with a hand up If first hand up doesn’t get it, the question goes to the other team pH QUIZ

11. Banana pH 5

12. pH 0 Battery Acid

13. Beer pH 4

14. Bicarbonate of Soda pH 8

15. Bleach pH 13

16. Blood pH 7.5

17. Coke pH 3

18. Drain Cleaner pH 14

19. pH 10 Hand Soap

20. Lemon Juice pH 2

21. Milk pH 6

22. Orange Juice pH 3

23. pH 7 Pure Water

24. Saliva pH 6

25. Sea Water pH 8

26. Stomach Acid pH 2

27. Toothpaste pH 9

28. Urine pH 6