HONOURS EXTRA 2: Acids and Bases Science 9H HONOURS EXTRA 2: Acids and Bases

Objectives By the end of the lesson you should be able to: Describe the similarities and differences between acids and bases Describe how to test for acids and bases

Types of Solutions There are 2 types of solutions: ACIDS (formula starts with H) BASES (formula ends with OH)

Acids Chemicals dissolved in water Cause indicators to change colour EX: vinegar, apples, coffee, milk, aspirin, stomach acid, lemon juice, HCl, H2SO4

Common acid formulas and names HCl HNO3 H2SO4 HNO2 HClO4 H2CO3 HBr H2CrO4 Hydrochloric acid Nitric acid Sulphuric acid Nitrous acid Perchloric Acid Carbonic acid Hydrobromic acid Chromic Acid

Bases Chemicals dissolved in water Causes indicators to change colour EX: soap, blood, eggs, baking soda, ammonia cleaner, Drano, Windex, TUMS, NaOH, LiOH

Indicators Dyes used to classify acids and bases They do this because they can change to different colours when they come into contact with acids and bases We use: - Litmus Paper (Red and Blue) - Bromothymol Blue - Phenolphthalein - Methyl Red and Methyl Orange - Indigo Carmine - Universal Indicator (U.I.)

pH Scale (Colours based on U.I.) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Very Slightly acidic acidic Slightly Very basic basic Neutral

Think about it? What happens if you mix a strong acid and a strong base? They will cancel each other out and end up as neutral BUT: what’s happened to all the chemicals??

Neutralizations Any time an acid and a base react a neutralization has occurred When mixed together they make a SALT and WATER acid + base  salt + water HX + YOH  YX + HOH or (H20)

Salts Always dissolve in water Have a crystal structure when not in water Have no effect on indicators Common example: Any ionic compound!!! NaCl, MgCl2, KBr,