Chemistry 0620 · IGCSE · Reversible reactions and equilibrium

Reversible reactions and equilibrium — practice question

(a(i))[1]

State how the solid’s colour changes during the reaction. Initial colour; final colour.

(a(ii))[1]

Write an equation for the thermal decomposition of copper(II) carbonate.

(b(i))[4]

Describe the tests for copper(II) ions and nitrate ions, and include the outcomes of each test.

(b(ii))[1]

Balance the chemical equation for the thermal decomposition of copper(II) nitrate. $\dots\text{Cu(NO}_3)_2 \rightarrow \dots\text{CuO} + \dots\text{NO}_2 + \dots\text{O}_2$

(c(i))[3]

A sample containing nitrogen dioxide and dinitrogen tetroxide at equilibrium was sealed in a gas syringe. The plunger was then pushed in, increasing the pressure in the syringe. The temperature stayed constant. State how the gas colour changed in the syringe. Explain your answer in terms of the position of the equilibrium.

(c(ii))[2]

Suggest an explanation for this observation in terms of the position of the equilibrium.

Worked solution & mark scheme

This 12-mark question has a full step-by-step worked solution and mark scheme. One marking point: Initial colour green, final colour black

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