Posted by Ashley on .
If a 930cm3 piston compresses the air in the cylinder to 1/8 its total volume, what is the pressure after the gas is compressed?

Chem 
Devron,
Not sure, but if since pressure in volume are inversely related you should see an increase in the pressure. so if volume decreased by 7/8, the pressure should increase by 7/8.

Chem 
DrBob222,
You don't list a pressure initially; the final pressure will be eight times (8x) the initial pressure.

Chem 
Devron,
Just a question, how do you get 8x the initial pressure when it decreased by 7/8?

Chem 
DrBob222,
p1 = some convenient number, say 2 atm.
v1 = 930 cc
p2 = ?
v2 = 930*1/8 = 116.25 cc.
p1v1 = p2v2
2*930 = p2*116.25
p2 = 2*930/116.25 = 16
16 is 8*2; p increased by a factor of 8.
If the volume is reduced to 1/2 its original volume the pressure must have been doubled.
If the volume is reduced to 1/3 its original volume the pressure must have been tripled.
If the volume is reduced to 1/10 its original volume the pressure must have been increased by 10 times (a factor of 10).
If the volume is decreased to 1/8 its original volume the pressure must have been increased by a factor of 8. 
Chem 
Devron,
Got it. Should have just done the math.