gases in the atmosphere

Question 1

what is the percentage of nitrogen in the air

Answer 1

78

Question 2

what is the percentage of exygen in the air

Answer 2

21

Question 3

what is the percentage of argon in the air

Answer 3

0.093

Question 4

what is the percentage of carbon dioxide in the air

Answer 4

0.04

Question 5

how can iron be uses to determine the percentage of oxygen in the air

Answer 5

iron reacts with oxygen in the air to firm rust, so iron will remove oxygen from the air

Question 6

how do you do the pratical to fins out the percentage of oxygen in the air

Answer 6

1) soake some iron wool in acetic acid and push the wool into a measuring culinder and invert the cylinder into a beaker of water.
2) record the starting position of the water- this is the starting volume of air
3) over time the level of water in the measuing cylinder will rise
4)this is because the iron reacts with the oxygen in the air to make irom oxide. The water rises to fill the space the oxygen took up.
5) leave this for a week and record the finishing position of the water-this is the final volume of air.

Question 7

how do calculate the percenatge of oxygen after doing the iron wool practial

Answer 7

start volume-final volume/ start volume * 100

Question 8

how do you use phosphorus to determine the percentage of oxygen in the air

Answer 8

1) Place the phosphorus in a tube and attach a glass syringe at either end. Make sure one is filled with aire and the other is empty.
2) heat the phosphorus and use the suringes to pass air over it to make phosphorus oxide.
3) as it reacts the amount of air in the syringes will decrease
4) measure the starting and final volumes of air by pushing all the air into one syringe
5) use the formula to calculate the percentage of air

Question 9

what does magnesium do when burnt in air

Answer 9

burns with a bright white flame and forms a white powder called magnesium oxide which is alkane

Question 10

what does hydrogen do when burnt in air

Answer 10

it has a pale blue flame and produces water which is neutral

Question 11

what does sulfur do when burnt in air

Answer 11

makes a pale blue flame and prouces sulfur dioxide which is acidic

Question 12

what does the thermal decomposition of metlal carbonated produce

Answer 12

carbon dioxide

Question 13

how do you do the thermal decomposition reaction

Answer 13

heat copper (ii) carbonate and collect the gas in a test tube bubble is through lime watet too see that is it carbon dioxide