Oxygen and Oxides Flashcards
Percentage gases in the air
78% Nitrogen
21% Oxygen
1% Argon
0.04% Carbon Dioxide
Describe an experiment involving copper to prove the percentage of oxygen in the air
Copper and oxygen react to form Copper Oxide.
1) Place copper in between two gas syringes, and then pass heat over the copper using a bunsen burner.
2) You can determine how much oxygen was used up by how much air is left, the oxygen will have reacted with the copper to form copper oxide.
Describe an experiment involving iron to prove the percentage of oxygen in the air
Iron reacts with oxygen to form rust.
1) Soak iron wool in acetic acid (acid acts as a catalyst)
2) Push the wool into a test tube, invert the tube into a beaker of water.
3) Over time the water level in the test tube will rise because the oxygen is being used to form rust.
4) Mark the start and end position, and calculate the amount of oxygen used.
How do you make oxygen?
Using hydrogen peroxide and manganese oxide as a catalyst.
-The hydrogen peroxide will decompose into water and oxygen. Manganese oxide speeds up the reaction.
Use a thistle funnel into a side-arm boiling tube into an inverted measuring cylinder in water.
What happens when you burn Magnesium in air? In Oxygen?
2Mg + O2 -> 2MgO - Bright white flame - White, powdery ash - Slight alkali solution when dissolved in water Reaction is far stronger in oxygen.
What happens when you burn Carbon in air? In Oxygen?
C + O2 -> CO2
- Orange/yellow flame if very strongly heated
- Carbon dioxide gas
- Slightly acidic when dissolved in water
Reaction is far stronger in oxygen.
What happens when you burn Sulfer in air? In Oxygen?
S + O2 -> SO2 - Tiny blue flame - Produces Sulfer dioxide - Acidic when dissolved in water Reaction is far stronger in oxygen.
Properties of Carbon Dioxide
- Colourless
- Odourless
- Gas
- Denser than air
- Slightly soluble in water
