Question

400cm³ of dry air was passed over heated copper powder in a hard glass tube until no further change. What volume of remained at the end of the experiment?​

Answer 1

Explanation:

I think there' will be a decrease in volume of the air.

Answer 2

Answer:320cm³

Explanation:

20% of oxygen is present in 100% of air

xcm³ of O2 is present in 400cm³ of air

Therefore

80cm³ of O2 is present in 400cm³ of air

Vol of air remained =400-80

=320cm³ of air

2Cu+O2=>2CuO

2mol. 1mol. 2mol

160cm³. 80cm³ 160cm³

Since O2 is used up in the reaction

Vol of air remained=320cm³

Mark please