# Chem

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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 - ,

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 - ,

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

• Chem - ,

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

• Chem - ,

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 - ,

Got it. Should have just done the math.