1. Acids and Bases

2. Think back to a time when you have eaten something very sour… Think back to a time when you have eaten something very bitter… What were your reactions to each?

3. SOUR!!

7. Bitter taste…

9. What causes some things to taste sour, and others to taste bitter?

10. It’s all about ACIDS and BASES  Its all about H + and (OH – ) ions

11. The pH Scale  Things you need to know about the pH scale The pH scale measures how acidic or basic a substance is The pH scale ranges from 0 -14 0 - 6.99 = acids 7.0 = neutral 7.01-14 =bases 0 = most acidic 14= least acidic / MOST BASIC

12. The pH Scale  Things you need to know about the pH scale The pH scale measures the concentration of H + ions in a solution A solution with a pH of 0 is very acidic, with a high H + concentration (lots of H + ions and not a lot of OH - ions) Acid- a compound that release H+ ions in a solution

13. The pH Scale  Things you need to know about the pH scale A solution with a pH of 14 is very basic, with a low H + concentration (lots of OH - ions and not a lot of H + ions) Base- compounds that remove H + ions from a solution A solution with a pH of 0 is neutral - neither acidic nor basic, with equal number of H + and OH - ions

14. Why do acids have more H + ions and bases have less H + and more OH - ions? Acid – donates H+ when added to aqueous solutions Base – breaks up into hydroxide (OH-) ions when added to a aqueous solution **An aqueous solution is a solution in which the solvent (what is doing the dissolving) is water

15. Where have you heard the word “buffer” in your everyday life?

16. For example, “Family and friends can provide a buffer against stress.” Definition Buffer - a person or thing that prevents incompatible or antagonistic people or things from coming into contact with or harming each other.

17. A Buffer in Science works the same way! Buffers- regulate the pH in an organisms – A compound that can bind to an H+ ion when the concentration increases, and can release H+ ions when the concentration decreases – Buffers “lock up” ions and helps the organism maintain homeostasis

18. BasicACIDIC If the pH in a stomach increases from a pH of 4 to a pH of 6, how does the hydrogen ion concentration change?

19. -If the pH in a stomach increases from a pH of 4 to a pH of 6, how does the hydrogen ion concentration change? -In other words, how many MORE H + ions do you have at a pH of 4 compared to a at pH of 6? pH Value H + Concentration Relative to Pure Water Example 010,000,000 battery acid 11,000,000 concentrated sulfuric acid 2100,000 lemon juice, vinegar 310,000 orange juice, soda 41,000 tomato juice, acid rain 5100 black coffee, bananas 610 urine, milk 71 pure water 80.1 sea water, eggs 90.01 baking soda 100.001 Great Salt Lake, milk of magnesia 110.000 1 ammonia solution 120.000 01 soapy water 130.000 001 bleach, oven cleaner 140.000 000 1 liquid drain cleaner

20. -If the pH in a substance increases from a pH of 4 to a pH of 6, how does the hydrogen ion concentration change? pH of 4 = 1,000 pH of 6 = 10 How does the hydrogen ion concentration change?

21. -If the pH in a substance increases from a pH of 4 to a pH of 6, how does the hydrogen ion concentration change? pH of 4 = 1,000 pH of 6 = 10 How does the hydrogen ion concentration change?  ANSWER - the hydrogen concentration decreased by a factor of 100

22. -If the pH in a substance increases from a pH of 2 to a pH of 5, how does the hydrogen ion concentration change? pH of 2 = 100,000 pH of 5 = 100 How does the hydrogen ion concentration change?

23. -If the pH in a substance increases from a pH of 2 to a pH of 5, how does the hydrogen ion concentration change? pH of 1 = 100,000 pH of 5 = 100  ANSWER - the hydrogen concentration decreased by a factor of 1,000

24. -If the pH in a substance decreases from a pH of 7 to a pH of 5, how does the hydrogen ion concentration change? pH of 7 = 1 pH of 5 = 100 How does the hydrogen ion concentration change?

25. -If the pH in a substance decreases from a pH of 7 to a pH of 5, how does the hydrogen ion concentration change? pH of 7 = 1 pH of 5 = 100  ANSWER - the hydrogen concentration increases by a factor of 100

26. Practice pH Lab!!