Chemistry 0620 · IGCSE · Air quality and climate

Air quality and climate — practice question

The table gives the mass of air pollutants, measured in nanograms, in $1000\,\text{cm}^3$ air samples collected across a four-month span.
(a(i))[1]

Name the pollutant whose concentration drops continuously from April to July.

(a(ii))[1]

Name the pollutant present at the lowest concentration in May.

(a(iii))[1]

Calculate the mass of carbon monoxide in $200\,\text{cm}^3$ of the air sample taken in April.

(b(i))[1]

State one source of the sulfur dioxide in the air.

(b(ii))[1]

Give one adverse effect of acid rain on buildings.

(b(iii))[1]

State one use of sulfur dioxide.

(c(i))[2]

Complete the chemical equation for this reaction: $\ldots\,\text{SO}_2 + \text{O}_2 \rightarrow \ldots\,\text{SO}_3$.

(c(ii))[1]

Complete the energy level diagram for the oxidation of sulfur dioxide to sulfur trioxide by writing these words on the diagram: reactants; products.

(c(iii))[1]

Explain, using information on the energy level diagram, how you know that this reaction is exothermic.

(d)[1]

State the meaning of the term catalyst.

(e)[1]

Identify which one of these pH values represents the pH of dilute sulfuric acid. Draw a circle around the correct answer. pH 2, pH 7, pH 9, pH 13.

(f)[1]

Identify one statement that best describes Brownian motion. Tick one box.

Worked solution & mark scheme

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