Gases in the atmosphere

Question 1

What is the apparatus needed for testing the % of oxygen?

Answer 1

-A through of water
-An inverted biruette with a stopcock
-Iron filings

Question 2

What is the method for testing the % of oxygen?

Answer 2

1. Measure the volume between the final mark and the stopcock
2. Fill the biruette with water up to the lowest mark (e.g 50ml) and then let it drain into a small measuring cylinder
   3.Measure the volume of the water
   4.Add water inside to moisten the biruette
3. Close the tap and put iron filings into the mouth of the biruette
   6.Invert the biruette into a trough of water and clamp it vertically
   7.Note and record the position of water
4. After 3-4 days note the final water level
   9.Then plug the results into the formula of old - new/ old x100 to get the precentage

Question 3

What is the precentage of Oxygen in the air?

Answer 3

21%