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A quantity of a gas has an absolute pressure of 400 kPa and an absolute temperature of 110 degrees kelvin. When the temperature of the gas is raised to 235 degrees kelvin, what is the new pressure of the gas? (Assume that there's no change in volume.)

A3.636 kPa
B854.46 kPa
C1.702 kPa
D510 kPa

Verified Answer :

AL2006


You can make sure there's no change in volume by keeping
your gas in a sealed jar with no leaks.  Then you can play with
the temperature and the pressure all you want, and you'll know
that the volume is constant.

For 'ideal' gases,

       (pressure) times (volume) is proportional to (temperature).

And if volume is constant, then

                 (pressure) is proportional to (temperature) .

So if you increase the temperature from 110K to 235K,
the pressure increases to  (235/110)  of where it started.

     (400 kPa) x (235/110)  =  854.55 kPa. (rounded)

Obviously, choice-b is the right one, but
I don't know where the .46 came from.
 

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