1. Identification of Acids and Bases and pH Scale Science 10 Ms. McGrath

2. Examples of acids  Lactic acid in muscles  Digestive acids in the stomach  Acids in certain fruits (pineapples, oranges)

3. Examples of bases  Soaps and cleaning products  Lidocaine (local anesthetic used by dentists)

4. How Can We Identify Acids & Bases? Many acids and bases look the same – transparent liquids How to tell them apart? Using indicators Indicator: a chemical that changes colour as the concentration of H + and OH - changes Example: phenolphthalein and litmus

5. Indicators Phenolphthalein: In the presence of an acid: colourless In the presence of a base: pink Litmus (from lichens) Blue litmus turns red in the presence of an acid Red litmus turns blue in the presence of a base

6. The pH Scale (the power of H) pH: a scale that indicates the concentration of hydrogen A measure of the acidity of a solution 0 to 14: pH < 7 = acid pH > 7 = base pH 7 = neutral pH is found using pH paper or a pH meter

7. Highest concentration of H+ (Lowest concentration of OH-) Highest concentration of OH- (Lowest concentration of H+)

8. Characteristics of Acids & Bases ACIDSBASES -Taste sour-Taste Bitter -pH less than 7-pH greater than 7 -Feel slippery

9. Neutralization Reactions Acid + Base = a specific double displacement reaction called neutralization Acid + Base → Salt + Water (always) Example: HCl (aq) + NaOH (aq) → NaCl (aq) + H 2 O (l)