J.R. S. answered 04/18/19
Ph.D. University Professor with 10+ years Tutoring Experience
P1 = original pressure = 1 atm (STP)
V1 = original volume = 160.5 ml
T1 = original temperature = 273K (STP)
P2 = final pressure = ?
V2 = final volume = 285.0 ml
T2 = final temperature = 28.5ºC + 273 = 301.5K
P1V1/T1 = P2V2/T2 and solve for P2
P2 = P1V1T2/V2T1 plug in the values and solve