A few question need help
1. Gas Percentage by volume Boiling point
Nitrogen 78% -196
Oxygen 21% -183
Argon About 1% -190
a)State one use of oxygen
b)The three main gases can be separated by fractional distillation of liquid air. Which gas will come out of the fractionating column first?
c)Briefly explain how the air is liquefied in the separation process mentioned in (b)
2) Three test tube are left for several day.
Test tube 1 Test tube 2 Test tube 3
Water,iron nail,air Iron nail,Solid calium chloride Iron nail,oil
In which of the test tube would rusting take place? Explain briefly your choice.
3)In another experiment.a student heated a small amount of copper(II) nitrate crystal in a test tube. Colourless droplets collected at the mouth of the tube. On the further heating,a brown gas was given off. A glowing splint was held at the mouth of the test tube.
(a) What colour was the copper(II)nitrate before heating?
b) What are the colourless droplets?
c)What happens to the glowing splint?
d)Name the brown gas given off.
4a)Name the compound of sulphur firned when the coal is burnt.
ai) Write a balanced chemical wquation for the formation of the compund in (a).
aii)Bane the acid formed when this compund reacts with rainwater.
b)What effect does 'acid rain' on
i)plants
ii)buildings
1a) Oxy-acetylene welding of steel
1b)
1c) Pressurization of air. Explanation....
2) Test tube 1. Rusting takes place when all the factors are present; Water, Iron, and Air.
3a) Blue
3b) Water [Take note --> of the phrase 'further heathing']
3c) Rekindle [ presences of Oxygen gas]
3d) NO2
4a) Sulphur dioxide
4ai) S + O2 --> SO2
4bi) Nutrients from the soil are dissolved by acid rain and water away, causing bad growth.
4bii) Corossion.
Hope to hear 2nd opinion. Thanks.