The pressure exerted by a gas is 2.5 atm while it has a volume of 150 cm3. What would be the volume of this sample of gas at standard atmospheric pressure?

Question

answers must show units, and must be rounded to the correct number of significant digits. Pressure for STP in atmospheric units (atm) is 1.0, STP for kilopascals (kPa) is 101.3 kPa

The pressure exerted by a gas is 2.5 atm while it has a volume of 150 cm3. What would be the volume of this sample of gas at standard atmospheric pressure?

Answer 1

Hi Jill,

We need to use the ideal gas law.

P * V = n * R * T.

This is a typical problem where the amount of gas (n) and the Temperature (T) are held constant.

So.....

P * V (initial) = P * V (final) or

 

P (Initial) = 2.5 atm

V (Iniital) = 150 cm^3

 

P (Final) = 1.0 atm

2.5 * 150 = 1.0 * V (Final)

Thus V (Final) = 2.5 * 150 / 1.0 = 375 cm^3

 

Depending on how your professor views significant figures, he(she) may want the answer to be 380 cm^3


If you have any questions, send me a comment.

Sincerely,

Ralph K.