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Nitrogen monoxide and oxygen combine to form nitrogen dioxide, according to the following equation - HSC - SSCE Chemistry - Question 20 - 2023 - Paper 1
Question 20
Nitrogen monoxide and oxygen combine to form nitrogen dioxide, according to the following equation. 2NO(g) + O2(g) ⇌ 2NO2(g) Keq = 2.47 × 10^12 A 2.00 L vessel is... show full transcript
Worked Solution & Example Answer:Nitrogen monoxide and oxygen combine to form nitrogen dioxide, according to the following equation - HSC - SSCE Chemistry - Question 20 - 2023 - Paper 1
Step 1
Step 2
Set Up the Expression for Equilibrium Concentration
Answer
Using the equilibrium expression and the reaction stoichiometry:
Let x be the change in concentration of NO(g) at equilibrium. According to the reaction, for every 2 mol of NO2 consumed, 2 mol of NO is produced:
- Initial: [NO2] = 0.90 mol L⁻¹, [NO] = 0 mol L⁻¹
- Change: [NO2] = -x, [NO] = +x
- At Equilibrium: [NO2] = 0.90 - x mol L⁻¹, [NO] = x mol L⁻¹
Therefore, the equilibrium expression can be written as:
. However, we know from the reaction equation that the relationship can be simplified based on concentration changes.
Step 3
Substitute Values and Solve
Answer
Substituting the values we know into the equilibrium expression:
Assuming that at equilibrium [O2] is a small value that can ignore for initial purposes:
Solving for x using the equilibrium constant will allow us to find the equilibrium concentration of NO(g).
Assuming large equilibrium constant indicates that NO2 will essentially convert completely, evaluate:
In this case, after simplifying the expressions, we find:
The conclusion from calculations shows the concentration of NO(g) is found to be: 8.69 × 10⁻⁵ mol L⁻¹.