How To Find Percentage Of Oxygen In The Air

Question 1

1.

Answer 1

Powdered copper in tube

Mass of tube measured

Question 2

2.

Answer 2

Tube heated

Air in syringes passed over copper while it was being heated

Question 3

3.

Answer 3

Each time air passed over copper, volume of air in the syringe measured

Question 4

4.

Answer 4

Copper changed from brown to black, mass of tube measured again

Question 5

Conclusion

Answer 5

Shows 21% of oxygen is in the air as 21% percent of the gas was used up (reacting with the copper)

Question 6

Sources of error

Answer 6

Tubing not airtight
Measuring volume at two different temperatures
Some air in tube may be more than 100cm3
Not cool enough at the end