gases in the atmosphere

Question 1

concentrations of gases in the atmosphere

Answer 1

78% nitrogen
21% oxygen
1% argon
0.04% carbon dioxide

Question 2

investigating percentages of oxygen in the armosphere

Answer 2

soak iron wol acetic acid (acid is a catalyst)
record starting position of water using the scale one the measuring cylinder
over time level of water will rise
this is because the iron reacts with the oxygen
level the measuring cylinder for around a week
use the equation
start volume-final volume/ start volume