(a) Describe the observation that would be made when----- i. Sulphur is heated from room...
(a) Describe the observation that would be made when-----
i. Sulphur is heated from room temperature till 1190C
ii. 50% trioxonitrate(V) acid acts on copper tunings
(b)i. State two gaseous pollutants that can be generated by burning coal.
ii. What gas is responsible for most of the explosions in coal mines?
iii. The mining of coal leads to environmental pollution. State two environmental effects of the mining activity.
iv. Explain briefly why coal burns more easily when it is in pieces than in lump form
v. Name the non-volitile residue after the destructive distillation of coal
(c)i. Describe a chemical test for water
ii.a. State the effect of boiling a temporary hard water
b. State the effect of adding sodium trioxocarbonate(IV) crystals to permanent hard water
iii. Write an equation for the process of boiling a temporary hard water
Explanation
(a)i. Its colour darkens from pale yellow to amber colour while its crystals become needle-like and at 119oC it begins to melt.
ii. The solution turns green, bubbles of colourless gas rise from the bottom of the mixture, but brown fumes of NO2 are produced and the solutions later turns blue.
(b)i - SO2
- CO2
- CO
- NO2
- H2S
ii. Methane
iii. - Contamination of soil
- Soil erosion
- Contamination of ground water
- Loss of biodiversity
- Formation of sink holes
iv. Because of the large surface area and the higher the area the faster the rate of reaction.
v. Coke
(c)i. The sample is added to anhydrous copper (II) tetraoxosulphate (VI) when it turns from white to blue confirms the presence of water/sample is added to anhydrous cobalt chloride/cobalt chloride paper when it turns from blue to pink indicates the presence of water.
ii(a) It softens temporary hard water
(b) To remove permanent hardness/soften hard water
iii. - Ca(HCO3)2 ---heat--->CaCO3 + CO2 + H2O + H2O
or
Mg(HCO3)2 ---heat--->MgCO3 + CO2 + H2O + H2O