1. Acids & Bases

2. two classes of chemicals that play an important role in everyday life classified based on their properties: PropertyAcidsBases molecular or ionic?molecularionic aqueous solution conducts electricity?yes feelslippery tastesourbitter

3. Acids produce hydrogen ions (H + ) when dissolved in water (aq) e.g. HCl splits into H + and Cl - ions in water react with substances in characteristic ways: Reaction with Metals acid + metal  hydrogen gas + ionic compound Example: hydrochloric acid with zinc HCl(aq) + Zn(s)  H 2 (g) + ZnCl 2 (aq)

4. Reaction with Carbonates acid + carbonate  carbon dioxide + water + ionic compound Example: vinegar with baking soda HC 2 H 3 O 2 (aq) + NaHCO 3 (aq)  CO 2 (g) + H 2 O(l) + NaC 2 H 3 O 2 (aq) acid chemical formulas typically begin with an H, and followed by (aq) acids show their properties only when dissolved in water

5. Naming Acids first group of acids are called binary – only 2 elements Acid nameChemical formulaUse Hydrofluoric acidHF(aq)Etching glass Hydrochloric acidHCl(aq)Cleaning concrete Hydrobromic acidHBr(aq)To make cleaning compounds Hydrosulfuric acidH 2 S(aq)Purifying metals

6. second group are oxyacids contain polyatomic ions more commonly encountered AcidChemical formulaRelated polyatomic ionPolyatomic ion name Acetic acidHC 2 H3O 2 (aq)C 2 H 3 O 2 − (aq)acetate nitric acidHNO 3 (aq)NO 3 − (aq)nitrate carbonic acidH 2 CO 3 (aq)CO 3 2– (aq)carbonate sulfuric acidH 2 SO 4 (aq)SO 4 2− (aq)sulfate phosphoric acidH 3 PO 4 (aq)PO 4 3− (aq)phosphate

7. Bases also known as alkaline many are ionic a substance that produces hydroxide (OH - ) ions when dissolved in water e.g. NaOH splits into Na + and OH - ions in water

8. Naming Bases BaseChemical formulaUses Sodium hydroxideNaOH(aq)Making paper calcium hydroxideCa(OH) 2 (aq)decreasing the acidity of lakes and soil ammonium hydroxideNH 4 OH(aq)window cleaners magnesium hydroxideMg(OH) 2 (aq)antacids aluminum hydroxideAl(OH) 3 (aq)heartburn medications sodium hydrogen carbonate (baking soda) NaHCO 3 (aq)making baked goods rise an abrasive cleaner

9. pH related to the number of hydrogen ions (H + ) in a solution power (or potential) of hydrogen pH scale indicates how acidic or basic a solution is ranges from 0 (very acidic) to 14 (very basic) pH of 7 is neutral

10. Acid-Base Indicators any substance that changes colour if an acid or a base is present IndicatorColour in AcidColour in Base bromothymol blueyellowblue phenolphthaleincolourlesspink phenol redyellowred/pink litmusredblue methyl orangeredorange/yellow