A gas that has a volume of 28 L, a temperature of 45 °C, and an unknown pressure has its volume increased to 34 L and its temperature decreased to 35 °C. If the pressure is measured after the change to be 2.0 atm, what was the original pressure of the gas?A.1.6 atmB.2.5 atmC.3.2 atmD.4.1 atm

The answer to your question is letter B. 2.5 atm

Explanation:

Data

P1 = ?                  P2 = 2 atm

T1 = 45°C = 318°K           T2 = 35°C = 308°K

V1 = 28 L             V2 = 34 L

Formula

Combined gas law

   P1V1/T1 = P2V2/T2

solve for P1

Substitution

  P1 = (318 x 2 x 34) / (28 x 308)

Simplification

  P1 = 21624 / 8624

Result

  P1 = 2.5 atm