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Nitrogen monoxide reacts with oxygen in a reversible reaction according to the equation shown below - CIE - A-Level Chemistry - Question 9 - 2015 - Paper 1
Question 9
Nitrogen monoxide reacts with oxygen in a reversible reaction according to the equation shown below. 2NO(g) + O2(g) ⇌ 2NO2(g) The partial pressures of each of the ... show full transcript
Worked Solution & Example Answer:Nitrogen monoxide reacts with oxygen in a reversible reaction according to the equation shown below - CIE - A-Level Chemistry - Question 9 - 2015 - Paper 1
Step 1
Calculate the equilibrium constant, Kc
Answer
The expression for the equilibrium constant, Kc, for the reaction is given by:
K_c = rac{[NO_2]^2}{[NO]^2[O_2]}
To find Kc using partial pressures, we convert the partial pressures directly to concentration terms. Using the ideal gas law, for small pressures, molarity and partial pressure are closely related.
From the table:
- Partial pressure of NO = 10 kPa
- Partial pressure of O2 = 30 kPa
- Partial pressure of NO2 = 20 kPa
So substituting these values into the equation:
Thus, the numerical value of the equilibrium constant Kc for this equilibrium is approximately 1.33 x 10^-1, which corresponds to Option B.