- #1

dalitwil

- 23

- 0

Ok guys, my last questions of the semester, Yay!

So I have two of them, one pertaining to a figure (attached), which has me terribly confused:

1.) In the figure (attached), if P1 = 133 kPa, V1 = 1123 cm3 and P2 = 200 kPa, V2 = 10000 cm3, what is the heat absorbed (+) or liberated (-), to the nearest joule, in Path 2? Assume the change in internal energy is 8900 J.

My Work (Reasoning):

I am assuming that W=0, simply because the path appears to be only vertical, So using ΔU=Q-W, we can say that ΔU=Q (because W=0) and ΔU is given as 8900 J, so wouldn't this be the answer? (It is not)

2.) 10 moles of a gas in thermal contact with an oil bath at temperature 300 K is compressed isothermally from a volume of 7541 cm3 to a volume of 1561 cm3. To the nearest joule what is the work done by the piston?

My Work:

W would simply equal nRT*ln(Vf/Vi)

Plugging in the knowns leaves me with -131

This is incorrect. (using the reasoning that ΔU=0)

Any ideas guys?

So I have two of them, one pertaining to a figure (attached), which has me terribly confused:

1.) In the figure (attached), if P1 = 133 kPa, V1 = 1123 cm3 and P2 = 200 kPa, V2 = 10000 cm3, what is the heat absorbed (+) or liberated (-), to the nearest joule, in Path 2? Assume the change in internal energy is 8900 J.

My Work (Reasoning):

I am assuming that W=0, simply because the path appears to be only vertical, So using ΔU=Q-W, we can say that ΔU=Q (because W=0) and ΔU is given as 8900 J, so wouldn't this be the answer? (It is not)

2.) 10 moles of a gas in thermal contact with an oil bath at temperature 300 K is compressed isothermally from a volume of 7541 cm3 to a volume of 1561 cm3. To the nearest joule what is the work done by the piston?

My Work:

W would simply equal nRT*ln(Vf/Vi)

Plugging in the knowns leaves me with -131

This is incorrect. (using the reasoning that ΔU=0)

Any ideas guys?