IGCSE Chemistry Environment topical questions

A student adds a few drops of a clear liquid to two anhydrous salts on a watch glass.

1. (a)State the colour change when the liquid is added to anhydrous cobalt(II) chloride.[1]
2. (b)State the colour change when the liquid is added to anhydrous copper(II) sulfate.[1]
3. (c)State what the two results prove about the liquid.[1]

A sample of clean, dry air is analysed.

1. (a)State the approximate percentage by volume of nitrogen in the sample.[1]
2. (b)Name the two other types of substance found in the remaining small fraction.[1]

Water for irrigation is pumped from a river that contains dissolved minerals, mud and bacteria.

1. (a)Name the gas from the air that the river water contains and that fish need to survive.[1]
2. (b)Name the treatment stage that removes the mud.[1]
3. (c)Name the treatment stage that kills the bacteria.[1]

A water company treats river water before pumping it to homes.

1. (a)Name the process that removes large suspended solids by allowing them to settle.[1]
2. (b)Name the process that removes smaller insoluble particles.[1]
3. (c)Explain why the water is passed through beds of carbon.[1]
4. (d)Explain why chlorine is added as the final stage.[1]

A town burns coal in an old power station and many cars on its roads are old models without modern exhaust fittings.

1. (a)Name the pollutant formed when fuel burns with too little oxygen.[1]
2. (b)State why this pollutant is dangerous to people.[1]
3. (c)Name the gas from the power station that causes acid rain.[1]
4. (d)Suggest one way the power station could reduce this emission.[1]

A farmer spreads ammonium sulfate fertiliser on a wheat field.

1. (a)Name the essential element that this fertiliser supplies.[1]
2. (b)Explain why the fertiliser must be applied again each season.[1]
3. (c)State one harmful effect if excess fertiliser is washed into a nearby river.[1]
4. (d)Write the word equation for making ammonium sulfate from ammonia solution and dilute sulfuric acid.[1]

A power station burns coal containing sulfur compounds and releases its waste gases through a tall chimney.

1. (a)Name the gas released by the coal that causes acid rain.[1]
2. (b)Describe how calcium oxide is used to reduce this emission.[2]
3. (c)Name one other gas that may be present in the waste gases and is toxic.[1]

A newspaper article claims that methane from cattle farming warms the planet as strongly as carbon dioxide from power stations.

1. (a)Explain how molecules of methane and carbon dioxide raise the average temperature of the Earth.[2]
2. (b)State two strategies, other than cutting fossil-fuel use, that reduce the effect of these gases on climate.[2]
3. (c)Write the symbol equation for photosynthesis.[1]

Nitrogen and oxygen are both unreactive at room temperature, yet they react inside a working car engine.

1. (a)Explain why the two gases combine in the engine.[2]
2. (b)Write the equation for the reaction in a catalytic converter that removes nitrogen oxide using carbon monoxide.[1]
3. (c)Name the two products of that reaction.[1]
4. (d)State one adverse effect of oxides of nitrogen, other than acid rain.[1]

A student claims: “I added anhydrous copper(II) sulfate to a colourless liquid and it turned blue, so the liquid must be pure water.”

1. (a)Explain the flaw in the student’s reasoning.[2]
2. (b)Describe a boiling-point test that would check the claim.[2]
3. (c)State the result that would support the claim that the water is pure.[1]