Use of Iron to calculate percentage volume of Oxygen in Air
- After several days, the water will rise up the burette and reach a constant level as the iron filings will react with all the oxygen in the air to form iron(III) oxide (rust).
- The water level will rise to replace the volume of oxygen lost during this reaction.
- E.g. the original water levels was 15 cm2 and is now 12 cm2. 3 cm2 has been used up.
3/15 x 100 = 20% Oxygen in air
Volume of Air at the Start = ( Total Burette Volume – Initial Burette Reading)
Volume of Oxygen Used (Reacted with Iron) = ( Initial Reading – Final Reading )
Percentage Volume of Oxygen Calculation:
Use of Phosphorus to calculate percentage volume of Oxygen in Air