Reversibility and dynamic equilibria
3 marks · EasyA reversible reaction between two gases in a sealed container reaches dynamic equilibrium.
State what happens to the concentration of each gas at equilibrium.
Explain why the concentrations behave this way at dynamic equilibrium.
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(a) They remain constant.
(b) Because the forward and backward reactions occur at equal rates so the amounts of each substance do not change overall.
(b2) —
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Marking points
B1 (a) · 1 mark · States that concentrations stay constant.
M1 (b) · 1 mark · Refers to forward and backward reactions being equal/occur at the same rate.
A1 (b) · 1 mark · Explains why this causes constant concentrations (no net change/amounts are balanced).
Worked solution
a) The concentration of each gas stays the same.
b) This is because the forward and backward reaction rates are equal, so the amount of each gas produced and used is balanced, resulting in constant concentrations.