The concentrations of reactants and products were studied for the following reaction - VCE - SSCE Chemistry - Question 5 - 2009 - Paper 1
Question 5
The concentrations of reactants and products were studied for the following reaction.
H2(g) + F2(g) ⇌ 2HF(g);
K = 313 at 25°C
In an experiment, the initial concen... show full transcript
Worked Solution & Example Answer:The concentrations of reactants and products were studied for the following reaction - VCE - SSCE Chemistry - Question 5 - 2009 - Paper 1
Step 1
Determine Initial Concentrations
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Answer
The initial concentrations of the reactants and products are given as follows:
[H2] = 0.0200 M
[F2] = 0.0100 M
[HF] = 0.400 M.
Step 2
Calculate Changes at Equilibrium
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Answer
Let the change in concentration of HF at equilibrium be represented by 'x'. The equilibrium concentrations can then be expressed as:
[H2] at equilibrium = 0.0200 - x M
[F2] at equilibrium = 0.0100 - x M
[HF] at equilibrium = 0.400 + 2x M.
Step 3
Use the Equilibrium Constant Expression
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Answer
The equilibrium constant K can be expressed as: K = rac{[HF]^2}{[H2][F2]}
Substituting the equilibrium concentrations into this expression, we obtain:
313=(0.0200−x)(0.0100−x)(0.400+2x)2
Step 4
Solve for x and Analyze Range of HF Concentration
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Answer
Since the initial concentration of HF is higher than the concentration of the reactants, at equilibrium, the production of HF would lead to the conclusion that the concentration of HF would be less than 0.400 M as some reacts when equilibrium is reached. Therefore, the answer is:
