1. C.6 Acid Contamination Acids and Bases

2. Acids Most acids are molecular compounds. All acids start with a hydrogen atom(s). Characteristics of acids: Sour taste (vinegar) React with bases to form salts and water. Conduct electricity Change color of acid-base indicators. Hydrosulfuric Acid H 2 S

3. Common Acids Sulfuric Acid: H 2 SO 4 Phosphoric Acid: H 3 PO 4 Nitric Acid: HNO 3 Hydrochloric Acid: HCl Acetic Acid: H 4 C 2 O 2

4. Sulfuric Acid: H 2 SO 4 Sulfuric acid is the most widely produced acid. 47 million tons a year is produced in the U.S. alone. Used in industry, as fertilizer, paint, dyes, detergents and automobile batteries.

5. Phosphoric Acid: H 3 PO 4 Phosphoric Acid contains phosphorus, which is an essential element for plants and animals. Used for fertilizers, animal feed and flavoring agent in beverages. Important for the manufacture of ceramics and detergents.

6. Nitric Acid: HNO 3 Nitric acid is a volatile, unstable liquid rarely used in industry. It denatures proteins, has a suffocating odor and stains skin. Used to make rubber, plastics, dyes and explosives.

7. Hydrochloric Acid: HCl Hydrochloric Acid is found in the stomach to digest food. Used to “pickle” (remove impurities) from iron and steel. Also used as a cleaning agent, food processing and in the activation of oil wells.

8. Acetic Acid: H 4 C 2 O 2 or CH 3 COOH Acetic acid is a clear, colorless, pungent smelling liquid. Used to make vinegar, synthesize chemicals and manufacture plastics. Also used to manufacture food supplements and as a fungicide.

9. Bases Characteristics of Bases: Taste bitter Change color of acid- base indicators. Feel slippery React with acids to produce salts and water. Conduct electricity

10. Calcium hydroxide: Ca(OH) 2 Magnesium hydroxide: Mg(OH) 2 Potassium hydroxide KOH Sodium hydroxide NaOH

11. Calcium hydroxide: Ca(OH) 2 Used in mortar, plaster and cement. Also used in paper pulping and de- hairing animal hides. Yuck. Calcium hydroxide plant

12. Magnesium hydroxide: Mg(OH) 2 The active ingredient in milk of magnesia. It reacts with the excess HCl in your stomach when you have a tummy ache and neutralizes it to form Magnesium chloride and water. Mg(OH) 2 + HCl  MgCl 2 + H 2 O Please balance this equation.

13. Potassium hydroxide KOH Used in the manufacture of some liquid soaps. Also used in dyes, chemicals and pesticides.

14. Sodium hydroxide NaOH A major industrial chemical. Used in drain and oven cleaners and converts animal fats to soap. Yuck. Sodium hydroxide pellets

15. pH Scale The pH scale indicates how many H + Ions are in a solution. A pH of 7 indicates a neutral solution. A pH of 7 -14 is a basic solution. A pH less than 7 is an acidic solution.

16. Ions with a 1 + charge Positive ions are called cations. Na + = sodium ion K + NH 4 + = ammonium ion Ca 2+ = calcium ion Ions released into the solar system

17. Ions with a 2 + charge Mg 2+ = magnesium ion Ca 2+ = calcium ion Ba 2+ = barium ion Zn 2+ = zinc ion Cd 2+ = cadmium ion Hg 2+ = mercury ion Cu 2+ = copper (II) ion Pb 2+ = lead (II) ion Fe 2+ = iron (II) ion

18. Ions with a 3+ and 4+ Charge Al 3+ = Aluminum ion Fe 3+ = Iron (III) ion Pb 4+ = Lead (IV) ion Sn 4+ = Tin (IV) ion

19. Ions with a negative 1 charge F - = Fluoride ion Cl - = Chloride ion Br - = Bromide ion I - = Iodide ion NO 3 - = Nitrate ion OH - = Hydroxide ion HCO 3 - = Hydrogen carbonate (bicarbonate) NOTE** Any ions with more than one element are called polyatomic ions.

20. Ions with a negative 2 charge O 2- = Oxide ion S 2- = Sulfide ion SO 4 2- = Sulfate ion SO 3 2- = Sulfite ion CO 3 2- = Carbonate ion

21. Ions with a negative 3 charge PO 4 3- = Phosphate ion PO 3 3- = Phosphite ion AsO 4 3- = Arsenate ion

22. Ionic compounds Finish the following equations and balance: K + O 2  ______ (potassium oxide) Mg + Cl 2  ____ (magnesium chloride) Na + Cl  ____ (sodium chloride) Your Turn on page 57.

23. C.8 Dissolving Ionic Compounds Ionic compounds dissolve because of the attractive forces between the ionic crystal and the polar ends of water molecules. It’s like a tug of war where the positive ions are attracted to the negative part of the water and the negative ions are attracted to the positive part of the water.

24. C.9 Heavy Metal Ion Contamination Heavy metals are generally heavier than many metals that are essential to human health such as Ca 2+ or K +. The most dangerous heavy metals are those of Pb 2+, Hg 2+ and Cd 2+ which are toxic even in small amounts. These ions can attach to proteins and cause damage to the nervous system, kidneys, liver, probable mental retardation, and even death. These metals are not removed as waste as they travel through the food chain—they remain in the body.

25. Lead Pb—Plumbum Lead can be present in many places. Once used for plumbing and a gasoline additive. Most of the lead ingested through water supplies is excreted in the urine. The limit for lead in a child’s blood is 10 micrograms per deciliter before medical intervention is recommended. It’s estimated that 1 out of 6 children under age six in the U.S. has a blood level over 10 micrograms per deciliter.

26. Mercury Hg—Hydragyrum Mercury is the only metal that is a liquid at room temperature. Mercury vapor is quite poisonous. Organic compounds containing methylmercury ions (CH 3 Hg) can get into the water supply and cause severe brain, nerve damage and death. It has also been linked to autism in children.

27. Cadmium Cd Used in photography and in paint manufacturing. It is very toxic producing headaches, coughing and vomiting. It can accumulate in the liver and kidneys causing irreparable damage. You Decide pg. 62/63

28. C.11 Molecular Substances in the River When the attractive forces between the nuclei of two or more atoms is not strong enough to transfer electrons, the electrons are shared. Polar molecules will dissolve in “polar” water. Nonpolar molecules will NOT dissolve in water. An example is oil. Therefore, “like” dissolves “like”. Part C: Summary Questions