Question

Nitrogen and hydrogen react in the Haber process to form ammonia. All substances are in the gas phase. If 0.505 atm of nitrogen and 0.739 atm of hydrogen react, what is the partial pressure of ammonia (in mmHg) when this reaction goes 75 complete. The volume and temperature are constant.

Answer 1

The balanced reaction will be

                 N2         +           3H2          -->              2NH3

Initial        0.505                    0.739                         0

Change       -x                       -3x                         2x

Equilibri        0.505-x            0.769-3x                    2x

Reaction goes to completion is 75%

so pressure of nitrogen after reaction = 25 / 100 X 0.505 = 0.126 atm

So x = 0.505-0.126 = 0.379 atm

so pressure of NH3 = 2X0.379 = 0.758 atm

so pressure of NH3 in mm Hg = 0.758 X 760 = 576.08 mmHg