A 1.00-L flask was filled with 2.00 moles of gaseous SO2 and 2.00 moles of gaseous NO2 and heated. After equilibrium was reached, it was found that 1.30 moles of gaseous NO was present. Assume that the reaction SO2 1 g2 1 NO2 1 g2mSO3 1 g2 1 NO1 g2 occurs under these conditions. Calculate the value of the equilibrium constant, K, for this reaction.

K = 3.45

Explanation:

In the reaction:

SO₂(g) + NO₂(g) ⇄ SO₃(g) + NO(g)

And K is:

K = [SO₃] [NO] / [SO₂] [NO₂]

Where [] are concentrations in equilibrium, as volume is 1L, [] could be taken as moles.

Equilibrium concentrations are:

[SO₂] = 2.00 moles - X

[NO₂] = 2.00 moles - X

[SO₃] = X

[NO] = X

AS moles of NO are 1.3 moles, X = 1.3 moles

Replacing:

[SO₂] = 0.7 moles = 0.7M

[NO₂] = 0.7M

[SO₃] = 1.3M

[NO] = 1.3M

K = 1.3M² / 0.7M²

- lead + phosphoric acid = hydrogen + lead(ii) phosphate