1. Acids & Bases

2. Indicators Indicators contain certain dyes which change color at various pH values. Indicators contain certain dyes which change color at various pH values. Red & Blue Litmus paper Red & Blue Litmus paper pH paper pH paper Phenolphthalein indicator solution Phenolphthalein indicator solution Universal indicator solution Universal indicator solution

4. pH scale Ranges from 1-14 Ranges from 1-14 If concentration of H + ions is higher than OH - ions it has a pH value lower than 7 (an acid) If concentration of H + ions is higher than OH - ions it has a pH value lower than 7 (an acid) If concentration of OH - ions is higher than H + ions it has a pH value higher than 7 (a base) If concentration of OH - ions is higher than H + ions it has a pH value higher than 7 (a base) If the concentration of H + ions and OH - ions are equal it has a pH value of 7 (neutral) If the concentration of H + ions and OH - ions are equal it has a pH value of 7 (neutral)

6. Acids Have a higher concentration of H + ions Have a higher concentration of H + ions Taste sour Taste sour Feel like water, but “sting” the skin Feel like water, but “sting” the skin Lemon juice, stomach acid, vinegar Lemon juice, stomach acid, vinegar Litmus paper: blue  red Litmus paper: blue  red pH of 1-6 pH of 1-6 Phenolphthalein indicator remains colorless Phenolphthalein indicator remains colorless Reacts with metals and carbonates Reacts with metals and carbonates

8. Bases Have a higher concentration of OH - ions Have a higher concentration of OH - ions Taste bitter Taste bitter Feel slippery Feel slippery Cleaners, soap, baking soda Cleaners, soap, baking soda Litmus paper red  blue Litmus paper red  blue pH of 8-14 pH of 8-14 Phenolphthalein indicator turns pink Phenolphthalein indicator turns pink Do NOT react with metals and carbonates Do NOT react with metals and carbonates

10. Neutral solutions Have an equal concentration of H + and OH - ions Have an equal concentration of H + and OH - ions Milk, pure water, blood Milk, pure water, blood Litmus paper: no change Litmus paper: no change pH of 7 pH of 7 Non reactive Non reactive

12. Strong Acids & Bases Dissociate fully into their ions Dissociate fully into their ions Conduct electrical current well Conduct electrical current well (strong electrolyte) (strong electrolyte) Strong acid: hydrochloric acid Strong acid: hydrochloric acid Weak acid: acetic acid Weak acid: acetic acid Strong base: sodium hydroxide Strong base: sodium hydroxide Weak base: ammonium hydroxide Weak base: ammonium hydroxide

13. Buffer a solution that resists changes in pH a solution that resists changes in pH Made with weak acids and weak bases Made with weak acids and weak bases The weak acid can react with added base The weak base can reacts with added acid The weak acid can react with added base The weak base can reacts with added acid Keeps pH at neutral range Keeps pH at neutral range

14. Warning All of the acids and bases used in this lab are corrosive to the eyes & skin. They are TOXIC by ingestion & direct inhalation. Avoid breathing the vapors & wear safety goggles at all times. All of the acids and bases used in this lab are corrosive to the eyes & skin. They are TOXIC by ingestion & direct inhalation. Avoid breathing the vapors & wear safety goggles at all times.