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# Chemistry Homework!?

A sample of neon gas at a pressure of 0.848 atm and a temperature of 20.4 °C, occupies a volume of 10.2 liters. If the gas is allowed to expand at constant temperature to a volume of 16.3 liters, the pressure of the gas sample will be
atm.

• (0.848 atm) x (10.2 L / 16.3 L) = 0.531 atm
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• Chemistry - confined gas problem....

You might be asking why Roger wrote 10.2L / 16.3L, and not 16.3L / 10.2L. Why that ratio and not the other?

Start with the combined gas law, and then cancel out the unit which is constant. Solve the equation for the unknown and then put in the corresponding values.

P1V1 / T1 = P2V2 / T2 ........ combined gas law
P1V1 = P2V2 ............. ......... constant T; aka Boyle's law
P2 = P1V1 / V2 .......... ......... solve or P2
P2 = 0.848 atm x 10.2L / 16.3L
P2 = 0.531 atm

One could argue that if the volume is increased, the pressure will decrease, and so you choose a ratio that gives a smaller pressure as the answer. That being said, I don't think that there is any substitute for starting with the applicable equation, solving it for the unknown and then putting in the appropriate numbers. The farther you go in chemistry and the more involved the problems become, the more useful it is to have a systematic way of solving problems.
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