(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
(a)
i. When sulphur is heated from room temperature till 1190°C, it changes from a solid state to a liquid state and then to a gaseous state. At 1190°C, sulphur melts to form a reddish-brown liquid and further heating leads to the vaporization of the liquid to form a gas with a pale blue flame.
ii. When 50% trioxonitrate(V) acid acts on copper tunings, brown nitrogen dioxide gas is produced. The copper is oxidized to copper(II) nitrate and the nitrogen dioxide is liberated. The brown coloration is due to the presence of the nitrogen dioxide gas.
(b)
i. Two gaseous pollutants that can be generated by burning coal are sulfur dioxide and carbon dioxide.
ii. Methane gas is responsible for most of the explosions in coal mines.
iii. Two environmental effects of coal mining activity are air pollution and water pollution.
iv. Coal burns more easily when it is in pieces because the surface area of the coal is increased, allowing more oxygen to react with it.
v. The non-volatile residue after the destructive distillation of coal is coal tar.
(c)
i. A chemical test for water is the anhydrous copper sulfate test. When anhydrous copper sulfate is added to water, it turns from white to blue, indicating the presence of water.
ii.
a. Boiling a temporary hard water causes the calcium and magnesium ions responsible for the hardness to precipitate out of solution, leaving soft water.
b. Adding sodium trioxocarbonate(IV) crystals to permanent hard water causes the calcium and magnesium ions responsible for the hardness to precipitate out of solution, leaving soft water.
iii. The equation for the process of boiling a temporary hard water is: Ca(HCO3)2 → CaCO3 + CO2 + H2O.
(a)
i. When sulphur is heated from room temperature till 1190°C, it changes from a solid state to a liquid state and then to a gaseous state. At 1190°C, sulphur melts to form a reddish-brown liquid and further heating leads to the vaporization of the liquid to form a gas with a pale blue flame.
ii. When 50% trioxonitrate(V) acid acts on copper tunings, brown nitrogen dioxide gas is produced. The copper is oxidized to copper(II) nitrate and the nitrogen dioxide is liberated. The brown coloration is due to the presence of the nitrogen dioxide gas.
(b)
i. Two gaseous pollutants that can be generated by burning coal are sulfur dioxide and carbon dioxide.
ii. Methane gas is responsible for most of the explosions in coal mines.
iii. Two environmental effects of coal mining activity are air pollution and water pollution.
iv. Coal burns more easily when it is in pieces because the surface area of the coal is increased, allowing more oxygen to react with it.
v. The non-volatile residue after the destructive distillation of coal is coal tar.
(c)
i. A chemical test for water is the anhydrous copper sulfate test. When anhydrous copper sulfate is added to water, it turns from white to blue, indicating the presence of water.
ii.
a. Boiling a temporary hard water causes the calcium and magnesium ions responsible for the hardness to precipitate out of solution, leaving soft water.
b. Adding sodium trioxocarbonate(IV) crystals to permanent hard water causes the calcium and magnesium ions responsible for the hardness to precipitate out of solution, leaving soft water.
iii. The equation for the process of boiling a temporary hard water is: Ca(HCO3)2 → CaCO3 + CO2 + H2O.
