- flames occur when substance undergoes combustion → which is rapid oxidation of a substance.
- combustion requires oxygen to occur + ceases when oxygen supply is cut
- fire blanket prevents oxygen in air from getting to flames → thus putting out fire
Air Percentages
- 78% nitrogen
- 21% oxygen
- 0.04% carbon dioxide
- 0.96% noble gases (mainly argon), water vapour and other gasses
nitrogen considered inert gas as the nitrogen-nitrogen triple bond is relatively strong and hard to break.
- thus reactions that involve nitrogen as a reactant have relatively high activation energies
Oxygen has many uses.
- essential for combustion
- used to supp patients with breathing disabilities
- 21% oxygen found in air is insufficient to oxygenate their blood.
- oxygen can also be used as oxidiser in welding - join metal together strongly
Argon and other noble gasses → provide inert env for high temp processes like in lightbulbs / thermal purification of copper and steel.
these gasses can be separated from each other by fractional distillation as they each have a unique BP.
atmospheric air → liquified → at very low temp → then allowed to slowly warm up inside a chamber attached to a fractionating column.
- nitrogen has lowest boiling point, so its first to boil off and be collected
| Component of Air | Boiling Point |
|---|---|
| nitrogen | -196 |
| argon | -186 |
| oxygen | -183 |
iron powder reacts with oxygen in air to produce iron(III)oxide