Step-by-step explanation:
According to Boyle's law, the volume of gas sample at constant temperature is inversely proportional to the pressure.
P * V = constant
Pi * Vi = Pf * Vf
We know the final volume and pressure, the initial volume and we have to find the initial pressure. We can replace the given values and solve it for Pi to get the answer to our problem.
Pi = ?
Vi = 5.35 L
Pf = 3.82 atm
Vf = 8.17 L
Pi * Vi = Pf * Vf
Pi = Pf * Vf/Vi
Pi = 3.82 atm * 8.17 L/(5.35 L)
Pi = 5.83 atm
Answer: the initial pressure was 5.83 atm.