Chemistry 0620 · IGCSE · Isotopes

Isotopes — practice question

(a)[2]

Define what isotopes are.

(b)[3]

Deduce how many protons, neutrons and electrons are present in the sulfide ion shown, $^{36}_{16}\text{S}^{2-}$.

(c(i))[1]

Complete Fig. 4.1 by adding these formulae to the diagram: $\text{S} + \text{O}_2$ and $\text{SO}_2$.

(c(ii))[1]

Explain how Fig. 4.1 shows that the reaction is exothermic.

(c(iii))[1]

Complete this sentence: An exothermic reaction transfers thermal energy to the ..............

(d(i))[2]

Label Fig. 4.2 so that the cathode and the electrolyte are shown.

(d(ii))[4]

State the products formed and the observations seen at the positive and negative electrodes.

(e)[3]

Complete the word equation for the reaction of dilute sulfuric acid with sodium carbonate: sulfuric acid + sodium carbonate → [BLANK] + [BLANK] + [BLANK].

(f)[1]

A few drops of thymolphthalein indicator are added to dilute sulfuric acid. State the colour of the solution.

Worked solution & mark scheme

This 18-mark question has a full step-by-step worked solution and mark scheme. One marking point: Atoms that have the same number of protons

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