Question

At a certain temperature, the equilibrium constant, Kc, for this reaction is 2.60

SO2(g) + NO2(g) <--> SO3(g) + NO(g)

At this temperature, calculate the number of moles of NO2(g) that must be added to 3.12 mol of SO2(g) in order to form 1.30 mol of SO3(g) equilibrium

Answer 1

SO2 (g) + NO2 (g) <---------------> SO3 (g) + NO (g)

3.12              x                                    0             0 ----------------------> initial

-y                  - y                                 +y           +y --------------------> dissociation

3.12 - y       x - y                                  y           y-----------------------> equilibrium

3.12 - 1.3      x-1.3                                 1.3         1.3   

1.82              x-1.3                                     1.3          1.3 (afetr below calculation)

at equilibrium SO3 moles given so

y = 1.3

Kc = 2.60

Kc = [ SO3][NO]/[SO2][NO2]

2.60 = (1.3 )^2 / (1.82) (x - 1.3)

x = 1.66

NO2 moles = x = 1.66

moles of NO2 that must be added = 1.66