Gases in the Atmosphere

Question 1

What is the percentage of nitrogen, oxygen, argon and carbon dioxide in the atmosphere?

Answer 1

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

Question 2

How can we use iron to determine the percentage of oxygen in the air?

Answer 2

1) Soak some iron wool in acetic acid, then push the wool into a measuring cylinder and invert the measuring cylinder into a beaker of water
2) Record the starting position of the water using the scale on the measuring cylinder(starting air volume)
3) Over time the level of the water in the measuring cylinder will rise. This is because the irons reacts with the oxygen in the air to make iron oxide. The water rises to fill the space the oxygen took up.
4) Leave the measuring cylinder for around a week or until the water level stops changing
5) Record the finishing position of the water(final air volume)

Question 3

What color will magnesium burn in oxygen?

Answer 3

Bright white flame

Question 4

What color will hydrogen burn in oxygen?

Answer 4

Orangey/yellow flame

Question 5

What color will sulfur burn in oxygen?

Answer 5

Pale blue flame

Question 6

Describe the formation of carbon dioxide from the the thermal decomposition of metal carbonates?

Answer 6

1) Heat a metal carbonate, you will get carbon dioxide and a metal oxide
2) This is an example of thermal decomposition which is when a substance breaks down into a simpler substance when heated