A 15.5 L balloon contains helium gas at a pressure of 840 mmHg. What is the final pressure, in millimeters of mercury, if the final volume is 9.25 L? (Please show your work in order to receive credit).

Question

A 15.5 L balloon contains helium gas at a pressure of 840 mmHg.  What is the final pressure, in millimeters of mercury, if the final volume is 9.25 L?  (Please show your work in order to receive credit).

SmokeyBrown · Answer

I think this question is based on the gas principle of "PV=nrT", which relates the pressure, volume and temperature of a given gas.

As @vocaloid knows, I suck at explaining and applying this principle, so maybe she can give it a go?

Vocaloid · Answer

In this case we can use Boyle's law rather than the full ideal gas law. Since we're only dealing with pressures and volumes here,

P1V1 = P2V2

P1 and V1 are your original pressure and volume (15.5L and 840 mmHg), while P2 and V2 are your final pressure and volume. You are given the final volume, so V2 = 9.25L. plug in and solve for P2.