unequal pressures

How Do You Calculate Final Pressure? Calculate the final pressure. p1 x V1 = p2 x V2 rearranging gives p2 = (p1 x V1) / V2 p2 = (101 300 x 5) / 2.8 = 180893 Pa. How do you find final pressure in ideal gas law? p = constant x T (right graph), or.