An important process for the production of acrylonitrile C3H3N is given by the following reaction

Question

2C3H6 + 2NH3 + 3O2 --> 2C3H3N + 6H2O
A 150 -L reactor is charged tot he following partial pressures at 25 C
P(C3H6) = .5 MPa
P(NH2) = .8 MPa
P(O2) = 1.5 MPa
What mass of acrylonitrile can be produced from this mixture (MPa = 10^6 Pa)?

It seems to me you must know either K_eq OR that the reaction proceeds to completion. Check my thinking.