Reversibility and dynamic equilibria
2 marks · NormalAmmonium chloride can decompose when heated to form ammonia and hydrogen chloride. The reaction is reversible.
Write a balanced chemical equation for this reaction, including the correct symbol for reversibility, and name one characteristic of a reversible reaction.
Work this out on paper, then compare with the answer and worked solution below. With a free account you can submit written answers for marking.
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\ce{NH4Cl(s) ⇌ NH3(g) + HCl(g)}; characteristic: can go forwards and backwards/does not go to completion/equilibrium is possible
Also accept: Can also accept 'both reactions occur at the same rate at equilibrium'; 'Concentrations remain constant at equilibrium'
Common mistakes: Missing the ⇌ symbol; Naming a characteristic of general reactions, not reversible
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Marking points
B1 · 1 mark · Correct reversible equation with ⇌ symbol: NH4Cl(s) ⇌ NH3(g) + HCl(g)
B2 · 1 mark · States a characteristic of a reversible reaction (can go both ways, or reaches equilibrium, etc.)
Worked solution
Characteristic: the reaction can occur in both directions (forward and reverse), and may reach an equilibrium.