Sulfur dioxide reacts with oxygen to produce sulfur trioxide according to the…
CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance
Problem
Sulfur dioxide reacts with oxygen to produce sulfur trioxide according to the equation
2 SO₂(g) + O₂(g) → 2 SO₃(g)
A kinetic study is carried out in a rigid container at constant temperature. The initial concentrations and their experimental uncertainties are
[SO₂]₀ = 0.500 ± 0.005 M
[O₂]₀ = 0.250 ± 0.003 M
[SO₃]₀ = 0 M
After 180 s, the spectroscopic measurement of SO₂ gives
[SO₂]₁₈₀ = 0.380 ± 0.004 M
Assume that the only process occurring is the stoichiometric reaction given above.
(1) Determine the concentration of SO₃ at 180 s and its absolute uncertainty, reporting the final result in the form [SO₃]₁₈₀ = value ± uncertainty M.
(2) Using your result from part (a), calculate the minimum possible concentration of O₂ remaining at 180 s. Discuss whether O₂ is still present in excess within the combined experimental uncertainties.