A sample of carbon monoxide occupies 2.44 L at 295.0 K and 771 torr. Find its volume at -47 degrees Celsius and 350 torr?

2 Answers
Jul 5, 2017

P1V1T1=P2V2T2; V24L

Explanation:

The key to solving this problem is to realize that a mercury column is used as a highly visual measure of pressure. One atmosphere of pressure will support a column of mercury that is 760mm high.

i.e. 1atm760mmHg

....And thus we can use the length measurement to represent pressure...We also realize that we must use absolute temperature, where absolute TemperatureC+273.15K.

So we solve for V2=P1V1T1×T2P2, and clearly the RHS gives an answer with units of volume.......

And so........

771mmHg×2.44L295K×226.1K350mmHg....

4L

Of course, I could have reduced each pressure measurement to units of atm, but the increase in volume is consistent with a decrease in PRESSURE, and the moderate decrease in temperature.

Do you see how the units cancel in the expression to give an answer in litres, i.e. as required for a volume?

Jul 5, 2017

4.18L

Explanation:

As there are a constant number of moles:
P1V1T1=P2V2T2

47C=226^circK#

2.44L=0.00244m3

771torr=102791.546Pa
350torr=46662.8288Pa

If P1V1T1=P2V2T2, then 102791.5460.00244295=46662.8288V2226.

V2=102791.5460.0024422629546662.8288=0.00411777473m30.00418m3=4.18L'