Topic 4

• Strong acids dissociates in water to produce H+ ions
• acid is below pH 7
• 1 pH unit has a 10x difference in acidity
• HCl = hydrochloric acid
• H2SO4 = sulphuric acid
• HNO3 = Nitric acid
• Bases are chemicals that react with acids to form salts
• Alkalis are soluble bases that dissolve in water to produce OH- ions
• Sodium, Potassium and Ammonium are always soluble
• Nitrates are soluble
• Acids and bases neutralise each other
• silver and lead chloride are insoluble
• lead, barium and calcium sulphate are insoluble
• common Carbonates and hydroxides are insoluble
• Making insoluble salts = Precipitation reaction
• For precipitation reaction you need TWO soluble salts
• To make soluble salt use an acid and insoluble base
• Hydrogen test is when lit splint gives a squeaky pop
• Test for Oxygen is if a glowing splint Relights
• CO2 test = limewater turns cloudy
• For testing chlorine blue litmus paper turns red than white
• ADD excess to neutralise
• Acid + Carbonate —> Salt + water + Carbon dioxide
• Acid + Metal —> Salt + Hydrogen
• Acid + Base ——> Salt + Water
• Titration is the process to work out the volume of acid/base to neutralise a given volume solution
• Pipette used to measure volume
• Conical flask used to contain liquid from pipette
• Burette allows to add small measured volumes
• Red and orange are acid in Universal indicator
• Blue and purple for alkali using universal indicator
• Phenolphthalein turns pink in alkali but is colourless in rest
• Methyl orange is red for acid
• methyl orange is yellow for alkali
• litmus paper is blue/red in neutral pH
• acid has a pH below 7