1. Acids & Bases They are everywhere.. In your food In your house EVEN IN YOU!!!!!

2. What is an acid?  An acid is a solution that has an excess of H + ions. It comes from the Latin word acidus that means "sharp" or "sour".  The more H + ions, the more acidic the solution.

3. Properties of Acids  Taste sour  Conduct electricity  Corrosive, which means they break down certain substances. Many acids can corrode fabric, skin, and paper Picture from BBC Revision Bites http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_b ases_1.shtml http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_b ases_1.shtml

4. Properties of Acids  Some acids react strongly with metals and form hydrogen gas  React with bases to form salts and water  Turn blue litmus paper red Picture from BBC Revision Bites http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_b ases_1.shtml http://www.bbc.co.uk/schools/ks3bitesize/science/chemistry/acids_b ases_1.shtml

5. Uses of Acids  Acetic acid - vinegar  Citric acid - lemons, limes, & oranges.  Ascorbic acid - Vitamin C which your body needs to function.  Sulfuric acid is used in the production of fertilizers, steel, paints, plastics, and in car batteries.  Hydrochloric acid – stomach acid

6. What is a base?  A base is a solution that has an excess of OH - ions.  Another word for base is alkali.

7. Properties of a Base  Feel slippery  Taste bitter  Caustic, which means they break down certain substances.  Conduct electricity. (Think alkaline batteries.)

8. Properties of a Base  Do not react with metals.  React with acids to produce salts and water.  Turns red litmus paper blue.

9. Uses of Bases  Bases – found in soaps, ammonia, and many other cleaning products.  The OH- ions interact strongly with substances, such as dirt and grease.  Chalk and oven cleaner contain bases.  Blood is a basic solution.

10. Acids and Bases – electrical conductors  Acids and bases both can conduct electricity because both contain ions  Ionic solutions are electrolytes - any substance containing free ions that make the substance electrically conductive

11. pH Scale pH is a measure of how acidic or basic a solution is. The pH scale ranges from 0 to 14. Acidic solutions have pH values below 7 Solutions with a pH of 0 are very acidic.

12. pH Scale A solution with a pH of 7 is neutral. Pure water has a pH of 7. Basic solutions have pH values above 7. Solutions with a pH of 14 are very basic

13. pH Scale A change of 1 pH unit represents a tenfold change in the acidity of the solution.

14. pH Scale For example, if one solution has a pH of 1 and a second solution has a pH of 2, the first solution is not twice as acidic as the second—it is ten times more acidic.

15. The relationship between H +, OH - and pH

16. Weak vs. Strong Acids  Strong acids ionize completely when placed in water. HCl, HNO 3, H 2 SO 4, HClO 4, HI, HBr  HCl  H + + Cl -  Weak acids do not ionize completely, they remain mostly intact and release fewer H + ions  CH 3 COOH ↔ CH 3 COO - + H +

17. Weak vs. Strong Baces  Strong bases ionize completely when placed in water. NaOH, LiOH, Be(OH) 2, Mg(OH) 2  Mg(OH) 2  Mg 2+ + 2(OH) -  Strong bases remove more H + ions when they are mixed with water (the OH - ions react with the H + ions)  Weak bases do not ionize completely, they remain mostly intact and release fewer OH - ions and remove fewer H + ions when they are mixed with water  NH 3 + H 2 O ↔ NH 4 + + OH -

18. Acid – Base Reactions  A reaction between an acid and a base is called neutralization. An acid-base mixture is not as acidic or basic as the individual starting solutions.

19. Acids and Bases react to form salts  When an acid and a base react, H + ions and OH - ions react to produce water and decrease the concentration of H + ions  The anions and cations that were connected with the H + ions and OH - ions react to form salts.  NaOH + HCl  Na + + Cl - + H + + OH -  NaOH + HCl  NaCl + H 2 O

20. Acid – Base reactions  Each salt listed in this table can be formed by the reaction between an acid and a base.  Salts are very important chemicals

21. Serial Dilution  Serial dilution is the stepwise dilution of a substance in solution.