When 5.0 moles of O2 are confined to a 24 liter container at 87 °C, the pressure is 6.0 atm. If the oxygen is allowed to isothermally expand to 36 liters, what is the new pressure?
Solution
Isothermal means constant temperature therefore, the gas law needed is Boyle's Law where
PiC = PfVf where
Pi = initial pressure
Vi = initial volume
Pf = final pressure
Vf = final volume
Solve Boyle's Law for Pf
Pf = ( PiVi ) / Vf
Pf = ( 6.0 atm x 24.0 L ) / 36.0 L
Pf = 144.0 atm L / 36.0 L
Pf = 4.0 atm
Answer
The new pressure of O2 is 4.0 atm.
