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Chemical equilibrium — Question 7

QCAA 2023, Paper 2 · 4 marks

Q7 · 2023 · Paper 2Unclassified4 marks

QUESTION 7 (4 marks)

When heated in a sealed container, solid mercury(II) oxide (HgO) decomposed to form metallic mercury (Hg) and oxygen gas (O2).

2HgO(s)

2Hg(l)

O2(g) +

⇌ Orange

Silver

Colourless

(a) Identify whether the reaction occurs in an open or closed system.

[1 mark]

(b) Explain why the colour of the system does not change once equilibrium is established.

[3 marks]

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