Chemistry question

Question

Suppose a sample of helium at 20 degrees Celsius occupies a volume of 9.00 L at a pressure of 6.85 atm. What volume does this helium sample occupy if the pressure is reduced to 6.21 atm while maintaining the temperature at 20 degrees Celsius

Answer 1

Constant temperature = Boyles Law

P1V1 = P2V2

(6.85 atm)(9.00 L) = (6.21 atm)(P2)

P2 = ((6.85)(9.00)/(6.21)

P2 = 9.93 atm