4.6 CHEMICAL TESTS

• Collect a sample of gas in a test tube • Attempt to ignite the gas with a lit splint • You will hear a squeaky pop

• Collect a sample of gas in a test tube • Attempt to ignite the gas with a lit splint • You will hear a squeaky pop

Combustion - hydrogen forming water

• Collect a sample of gas in a test tube • Place a glowing splint in the test tube • The splint will relight

Combustion of the wood - Pure O2 is more concentrated that the O2 in normal air (splint combusts faster)

• Add anhydrous copper (II) sulfate to water • Will turn from white to blue

• Measure the boiling point • Closer to 100c = more pure

• Bubble a sample of gas through limewater • A white precipitate forms (goes cloudy)

• Bubble a sample of gas through limewater • A white precipitate forms (goes cloudy)

• Limewater is saturated calcium hydroxide solution • Calcium Carbonate is the white precipitate formed with water when reacting

• Place damp blue litmus paper in a sample of the gas • It wil be bleached white

• Chlorine dissolves into the dampness (water) and removes colour from blue litmus • It is a good bleaching agent

• Chlorine dissolves into the dampness (water) and removes colour from blue litmus • It is a good bleaching agent

• Place damp red litmus paper in sample of gas • It will turn blue

• Ammonia acts as a base accepiting H+ ions from water • OH- ions remain • Alkaline so turns litmus blue • Ammonia + water -> Ammonium + hydroxide

• Dip a piece of nichrome / platinum wire into hydrochloric acid to clean the wire • Dip the wire into the sample of solid or solution • Place the tip of the wire into a non-luminous bunsen flame

Li+

Na+

K+

Ca 2+

Cu 2+

Red

Yellow

Lilac