Question

For the chemical equation SO 2 ( g ) + NO 2 ( g ) − ⇀ ↽ − SO 3 ( g ) + NO ( g ) SO2(g)+NO2(g)↽−−⇀SO3(g)+NO(g) the equilibrium constant at a certain temperature is 2.70 . 2.70. At this temperature, calculate the number of moles of NO 2 ( g ) NO2(g) that must be added to 2.99 mol SO 2 ( g ) 2.99 mol SO2(g) in order to form 1.30 mol SO 3 ( g ) 1.30 mol SO3(g) at equilibrium.

Answer 1

Answer : The number of moles of
`NO_2` added must be, 0.37 mol

Explanation :

The given chemical reaction is:

`SO_2(g)+NO_2(g)\rightleftharpoons SO_3(g)+NO(g)`

Initial mol. 2.99 x 0 0

At eqm. (2.99-1.30) (x-1.30) 1.30 1.30

= 1.69

The expression for equilibrium constant is:

`K_c=([SO_3][NO])/([SO_2][NO_2])`

Now put all the given values in this expression, we get:

`2.70=((1.30)* (1.30))/((1.69)* (x-1.30))`

x = 1.67 mol

The moles of
`NO_2` added = (x-1.30) = (1.67-1.30) = 0.37 mol