Chemistry 5070 · O Level · Reversible reactions and equilibrium

Reversible reactions and equilibrium — practice question

Calcium is a metal belonging to Group II of the Periodic Table.
(a)[2]

Calcium can serve as a reducing agent. Describe a test for reducing agents. test observations

(b)[2]

A calcium ion is shown by the symbol $^{44}_{20}\text{Ca}^{2+}$. Deduce how many electrons and neutrons are present in this ion. number of electrons number of neutrons

(c(i))[2]

When calcium carbonate is heated in a sealed container, an equilibrium mixture develops. $\text{CaCO}_3(s) \rightleftharpoons \text{CaO}(s) + \text{CO}_2(g)$ The forward reaction is endothermic. Describe and explain the effect, if any, on the position of equilibrium when a hole is made in the container.

(c(ii))[2]

Describe and explain the effect, if any, on the position of equilibrium when temperature is raised.

(d)[1]

On heating, calcium oxide reacts with chlorine to produce calcium chloride and a gas that relights a glowing splint. Complete the equation for this reaction. $2\text{CaO} + \ldots \rightarrow \ldots\text{CaCl}_2 + \ldots$

(e)[1]

Calcium chloride dissolves in water. Name one other calcium salt that is soluble in water.

Worked solution & mark scheme

This 10-mark question has a full step-by-step worked solution and mark scheme. One marking point: introduce acidified potassium manganate(VII)

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