Question

Nitrogen dioxide and water react to form nitric acid and nitrogen monoxide, like this:

Answer 1

Answer:

0.29

Explanation:

Step 1: Write the balanced equation at equilibrium

3 NO₂(g) + H₂O(l) ⇄ 2 HNO₃(aq) +  NO(g)

Step 2: Calculate the molar concentration of the substances

We will not calculate the molarity of H₂O because pure liquids are not included in the equilibrium constant. We will use the following expression.

Molarity = mass of solute / molar mass of solute × liters of solution

Since the volume of the vessel is missing, we will assume it is 1 L to see the procedure.

[NO₂] = 22.5 / 46.01 g/mol × 1 L = 0.489 M

[HNO₃] = 15.5 g / 63.01 g/mol × 1 L = 0.246 M

[NO] = 16.6 g / 30.01 g/mol × 1 L = 0.553 M

Step 3: Calculate the value of the equilibrium constant Kc for this reaction

Kc = [HNO₃]² × [NO] / [NO₂]³

Kc = 0.246² × 0.553 / 0.489³

Kc = 0.29