1 Can you name some common acids and bases that we use everyday?

2 Properties of Acids and BasesProduces H+ ions in a solution (soon combines w/ H2O to form hydronium ions H3O+). Produces OH- ions in a solution (hydroxide ions) Examples: HCl, HF Examples: NaOH, KOH Bonds with non-metals Bonds with metals Caustic – another word for acid Alkali – another word for base Both can be electrolytes producing electricity

3 Taste of Acids and BasesHave you ever taken a bite out of a lemon? Lemon juice is an acid, and acids can taste sour. Base Baking soda has a bitter taste that most people do not like. Baking soda is a base, and bases can taste bitter. Neutral Water is not an acid or a base, it is neutral and has no particular taste. Please do not ever taste strong acids or strong bases or any other chemicals that are not food!

4 How Do Acids and Bases Feel?If you are slicing lemons and some of the juice gets into a cut on your finger, it stings. Acids sting! Acid If you have ever spilled bleach or soap on the floor, you may have noticed that it is slippery. Bases are slippery. Base A neutral substance such as water is a good choice for cleaning up acids and bases because it does not sting and it is not slippery. Neutral Please do not ever touch strong acids or strong bases because they can be harmful to your skin and may damage sensitive tissues such as your eyes.

5 Common Acids and Bases Acids Bases gastric juice in stomach soapsbatteries cleaners vinegar citrus carbonated drinks Aspirin fertilizers Bases soaps ammonia deodorants laxatives fertilizers lime-sweetens soil lye-oven cleaner

6 Strength of Acids Strong Acids – Weak Acids – pH low - between 0-3pH between 3-6 Diluted – release a FEW H+ ions in water Concentrated – release a lot of H+ ions in water Examples: HNO3 – nitric acid HCl-hydrochloric acid Examples: Citric Acid in Fruits Carbonic Acid – Soda Vinegar Corrosive Acids – react with metals Examples: H2SO4 HCl

7 Strength of Bases Strong Bases – Weak Bases – pH high - between 10-14pH between 8-10 Concentrated – release a lot of OH- ions in water Diluted – release a FEW of OH- ions in water Examples: Mg(OH)2 – Milk of Mg NH4OH – household ammonia Examples: NaOH – Drano Bleach Corrosive bases-react with metals Bases react with fats, grease and oils – that’s why they make good cleaners.

8 Is there a difference? Strength-depends on how completely a compound is pulled apart to form ions when dissolved in water. (weak or strong) Concentration-refers to the amount of acid or base dissolved in solution. (dilute or concentrated) It is possible to have diluted strong acids & bases as well as solutions of concentrated weak acids and bases.

9 Indicators …are scientific aids that tell whether something is an acid, a base or neutral substance. …can sometimes tell the concentration of H+ or OH- ion in the solution.

10 The pH Scale pH is based on the concentration of H+ ions in solutionTo determine if a substance is an acid or a base we use the tool called the … The pH Scale pH is based on the concentration of H+ ions in solution H+ pH scale is based on powers of 10 H+

11 The pH Scale Neutral More Acidic H+ More Basic OH- 1 2More Acidic H+ More Basic OH- Neutral 1 1,000,000X 100,000X 10,000X 1,000X 100X 10X 2 The stronger the acid – the lower the number. 3 4 5 6 The pH Scale 7 X O,1X 0.01X 0.001X 0.0001X X X X 8 9 10 The stronger the base – the higher the number. 11 12 13 14

12 O OH- Acid > O OH- Base > O OH- = NeutralIf there are more H+ than OH-, then the chemical is an acid. H+ O H OH- Acid > If there are Less H+ than OH-, then the chemical is a base. H+ O H OH- Base > If there are equal amounts of H+ and OH-, then the chemical is neutral. H+ O H OH- = Neutral

13 Types of Indicators pH meter-used to determine pH by immersing electrodes into solution and read a dial indicating strength of acid or base. Litmus paper is used as an natural paper indicator made from moss for acids and bases. Acidic turns blue litmus  to red Basic turns red litmus  to blue pH indicator - a chemical that changes color at different pH values, ex. Phenolphthalein Acid  turns Clear / Colorless Base  turns Pink/Purple

14 Neutralization of Acids and Bases+  Acid Base Neutral + = Bases and acids neutralize each other. Mixing equal amounts of similar strength acids and bases produces a neutral substance.

15 The neutral substance that it produces is SALT and WATER.Example: HCl + NaOH → H2O + NaCl Strong Acid Strong Base Water Salt

16 HCl breaks into H+ and Cl-Ionization breaking apart of certain polar substances (such as an acid) to form ions HCl breaks into H+ and Cl-

17 Breaking apart of an ionic compound (such as a base) to form ionsDissociation Breaking apart of an ionic compound (such as a base) to form ions Strong Base Weak Base H2O Na+ OH- Na+ NH4+ NH4+ Solution Solution H2O NH3 Na+ Na+ OH- OH- NH3 OH- OH- OH- NaOH Na+ + OH- NH3 + H2O NH4+ + OH-

18 Producing ElectricityElectrolytes-a substance that separates into ions or forms ions in a solution, and conducts electricity (both acids and bases do this) Nonelectrolytes-substances that do not form ions when dissolved in a solution, does not conduct electricity

19 Acid Rain Unpolluted rain is slightly acidic about pH 5.6Each point you drop on the pH scale is 10 times stronger. Any rain below 5.6 is called acid rain. Rain in urban areas is usually 4.5 and can even get as low as 4.2.

20 Acid Rain Rain or any other precipitation is naturally acidic because it mixes with carbon dioxide and forms carbonic acid. However, gases released into the atmosphere from burning fuels such as coal and oil increase the acidity in rain. Sulfur oxides from factories Nitrogen oxides from autos These combine with oxygen and H20 to form sulfuric acid and nitric acid.

21 What effects does acid rain have?Food Chain can kill animals that live in water. can kill plants which rely on rain as their water source. dissolve away nutrients for plant growth Effects Buildings and Statues Marble, limestone will react to acid by dissolving it away

22 How A Dead Lake Is CreatedFossil fuels are burned (coal, oil, natural gas) Sulfur oxide and nitrogen oxide are released into the air Sulfur oxide and nitrogen oxide mix with water vapor in clouds Rain, snow fall to Earth with sulfuric acid and nitric acid pH in lakes decreases below 5.6 Plankton die (animals and plants) Fish that feed on plankton have no food and die Food chain impacted.