Water And %of Oxygen

Question 1

What is the Water test?

Answer 1

Anhydrous copper sulphate will turn blue when water is added to it

Question 2

What is the test for the % of oxygen?

Answer 2

Pass 100 cm cubed of air through two syringes connected by a tube containing copper wool.
The copper will turn black.
Wait for it to cool before measuring the new amount of air
The amount that has gone is how much oxygen there was