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The set-up below was used to investigate properties of the components of air:

      

The set-up below was used to investigate properties of the components of air:
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(i) State two observations made during the experiment

(ii) Write two chemical equations for the reactions which occurred

(iii) The experiment was repeated using burning magnesium in place of phosphorous.
There was greater rise of water than in the first case. Explain this observation

(iv) After the two experiments, the water in each trough was tested using blue and red litmus
papers. State and explain the observations of each case.
(a) Phosphorous experiment
b) magnesium experiment

(v) Briefly explain how a sample of nitrogen gas can be isolated from air in the laboratory

  

Answers


Maurice
(i) White fumes form in the gas jar which disappear after sometime.
- The level of water rises in the gas jar.

(ii) P(s) + O2(g) ------>P2O5(s)
P2 O(s) + 3H2O(l)--------->2H4PO4(aq)

(iii) Magnesium react with oxygen and nitrogen hence greater of fraction of air is used.

(iv) (a) Blue litmus changed to red as remained red. The solution was acid due to phosphoric
(b) Red litmus changed to blue as blue remained blue due to formation of basic magnesium hydroxide ammonia solution.

(v) – Pass air over conc. KOH / NaOH to absorb CO2
- Pass the remaining gases over hot copper solid which reacts with oxygen.
- Collect the remaining gas over water. The gas is mainly nitrogen.
maurice.mutuku answered the question on October 14, 2019 at 06:21


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