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Boyle's Law Example Problem

Gas Law Example Problem


Boyle's gas law states the volume of a gas is inversely proportional to the pressure of the gas when temperature is held constant. This example problem uses Boyle's law to find the volume of a gas when pressure changes.


A balloon with a volume of 2.0 L is filled with a gas at 3 atmospheres. If the pressure is reduced to 0.5 atmospheres without a change in temperature, what would be the volume of the balloon?


Since the temperature does not change, Boyle's law can be used. Boyle's gas law can be expressed as:

PiVi = PfVf

Pi = initial pressure
Vi = initial volume
Pf = final pressure
Vf = final volume

To find the final volume, solve the equation for Vf:

Vf = PiVi/Pf

Vi = 2.0 L
Pi = 3 atm
Pf = 0.5 atm

Vf = (2.0 L)(3 atm)/(0.5 atm)
Vf = 6 L/0.5
Vf = 12 L


The volume of the balloon will expand to 12 L.

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