We have to calculate the initial volume of a gas when a gas expands from a pressure of 1.60 atm to a pressure of 695 torr at constant temperature.

**We will solve this problem using the Boyle’s law.**

**Boyle’s law** states that the *volume of a gas varies inversely with the pressure applied on it.*

$\overline{){\mathbf{V}}{\mathbf{}}{\mathbf{\propto}}{\mathbf{}}\frac{\mathbf{1}}{\mathbf{P}}}$

**We can remove the proportionality sign to add “=” sign and a constant.**

$\mathbf{V}\mathbf{}\mathbf{=}\mathbf{}\mathbf{constant}\mathbf{\times}\frac{\mathbf{1}}{\mathbf{P}}\phantom{\rule{0ex}{0ex}}\overline{){\mathbf{PV}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}{\mathbf{constant}}}$

**For two states of a gas:**

$\overline{){{\mathbf{P}}}_{{\mathbf{1}}}{{\mathbf{V}}}_{{\mathbf{1}}}{\mathbf{}}{\mathbf{=}}{\mathbf{}}{{\mathbf{P}}}_{{\mathbf{2}}}{{\mathbf{V}}}_{{\mathbf{2}}}}$

An ideal gas at a pressure of 1.60 atm is contained in a bulb of unknown volume. A stopcock is used to connect this bulb with a previously evacuated bulb that has a volume of 0.810 L as shown here. When the stopcock is opened the gas expands into the empty bulb.

If the temperature is held constant during this process and the final pressure is 695 torr , what is the volume of the bulb that was originally filled with gas?

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What scientific concept do you need to know in order to solve this problem?

Our tutors have indicated that to solve this problem you will need to apply the Chemistry Gas Laws concept. If you need more Chemistry Gas Laws practice, you can also practice Chemistry Gas Laws practice problems.