Summary Gases In The Atmosphere

Gases In The Atmosphere
These figures in the following pie-chart apply to only
dry, unpolluted air. Normal air can contain 0%-4% of
water vapour.




Composition of the Air


DETERMINING THAT AIR CONTAINS ABOUT ONE-FIFTH OF OXYGEN

Activity 1 : Using Copper




Initial volume of air = 100 cm3 Observations :
Final volume of air = 79 cm3
Overall reaction:  Reddish brown copper turns
black.
2Cu (s) + O2 (g) 2CuO (s)  Some gases are collected in the
second syringe.
Vol. of oxygen = Initial vol. of air – Final vol. of air % of oxygen = Vol. of oxygen
× 100%
= 100 -79 Initial vol. of air
= 21 cm3 = 21
× 100%
100