GASES & ION
- Created by: olivialcock
- Created on: 24-08-16 18:06
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- GASES & ION
- TESTS FOR GASES
- HYDROGEN:
- TEST: mix with air and ignite using a lit splint
- RESULT: burns with a squeaky pop
- OXYGEN:
- TEST & RESULT: relights a glowing splint
- AMMONIA:
- TEST: damp red litmus paper
- RESULT: litmus paper turns blue
- CHLORINE
- TEST: damp blue litmus paper
- RESULT: litmus paper turns red and then bleaches white
- CARBON DIOXIDE
- TEST: bubbled through limewater
- RESULT: turns the limewater cloudy
- HYDROGEN:
- GASES IN THE AIR
- 78% Nitrogen
- 21% Oxygen
- 0.93% Argon
- Argon is known as a noble gas because it is very unreactive
- 0.04% Carbon Dioxide
- Water vapour
- TESTING FOR CATIONS
- FLAME TESTS
- Lithium = red
- Sodium = orange
- Potassium = lilac
- Calcium = brick red
- HOW TO CARRY OUT A FLAME TEST
- 1. Clean a platinum wire loop by dipping it into hydrochloric acid and putting it in a flame (should burn without colour)
- 2. Once the loop is clean, you can dip it into the sample you want to test and then put it back in the flame
- TESTING FOR AMMONIUM IONS
- TEST: add sodium hydroxide to the solid/solution being tested
- RESULT: if ammonium ions are present then a pungent smelling gas is produced
- PRECIPITAT-ION REACTIONS
- METHOD: add sodium hydroxide solution to the solution being tested
- RESULTS:
- COPPER (II) blue precipitate
- IRON (II) sludgy green precipitate
- IRON (III) red/brown precipitate
- FLAME TESTS
- OXYGEN
- MAKING OXYGEN
- Pure oxygen can be made using hydrogen peroxide (H202)
- Hydrogen peroxide will decompose into water and oxygen
- The decomposition is really slow but the rate of the reaction can be increased with a catalyst
- CATALYST = Manganese oxide
- A catalyst speeds up a reaction without being used up itself
- CATALYST = Manganese oxide
- Methods of collection
- Gas syringe
- Over water
- WORKING OUT THE % OF OXYGEN IN THE AIR
- COPPER EXPERIMENT
- METHOD
- 1. 100cm3 of air is passed over copper (which is being heated)
- 2. When copper is heated, it reacts with oxygen in the air to make copper (II) oxide
- So the reaction uses up oxygen
- Therefore the volume of air decreases by about 20% (percentage of oxygen in the air)
- So the reaction uses up oxygen
- METHOD
- IRON OR PHOSPHOR-OUS EXPERIMENT
- % of oxygen = vol of oxygen used // vol of air at start x100
- iron + oxygen + water ---> hydrated iron (II) oxide
- METHOD:
- 1. Iron wool is soaked in acetic acid and pushed into a test tube
- CATALYST = ACETIC ACID
- 2. The test tube is then inverted into a beaker of water
- 3.Over time the level of water in the test tube will rise because the iron reacts with the oxygen to make iron oxide
- 1. Iron wool is soaked in acetic acid and pushed into a test tube
- COPPER EXPERIMENT
- MAKING OXYGEN
- CARBON DIOXIDE
- MAKING CARBON DIOXIDE
- Dilute hydrochloric acid reacts with calcium carbnate to produce carbon dioxide
- Pieces of calcium carbonate (marble chips) are put in the bottom of a flask and dilute hydrochloric acid is added
- The dilute hydrochloric acid reacts with the calcium carbonate to produce...
- 1. Calcium chloride
- 2. Water
- 3. Carbon dioxide gas
- Methods of collection
- a gas syringe
- using downward delivery (used to collect gases that are heavier than air)
- MAKING CARBON DIOXIDE
- TESTS FOR GASES
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