please help...?

Question

Assuming that the volume and temperature of the reaction mixture remain constant, what is the percent change in pressure if the reaction goes to completion?

A(g)+ 2B(g) ----->2 C(g)

A reaction mixture initially contains 1.4 L of A and 1.8 L of B.

Answer 1

Since from the balanced equation you are going from 3 moles of gas to 2 moles of gas, the pressure (at constant T and V) will change proportionally. So, the final pressure will be 2/3 of the initial pressure. Since pressure is directly proportional to the amount of gas, your final pressure will be 66.7% of your initial pressure, so will decrease by 33.3%.