Work done during expansion of a gas

In summary, the conversation discusses the calculation of internal energy using the formula Eint=Q+W. The speaker notes that Q is smaller than the area under the curve, leading to a negative value for internal energy. However, when they try to calculate the work done using the graph, they get a much larger value, resulting in a negative answer. The other person suggests showing their work and confirms that they also get a negative answer. The conversation ends with the speaker expressing frustration with mistakes in their cengage material.
  • #1
tanzerino
48
0
[PLAIN]http://img101.imageshack.us/img101/8176/24851738.png

it is definetaly negative as Eint=Q+W
and Q is smaller than the area under curve taking care of the scaling of pressure in atm.
but what i get is -1.5x10^6
 
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  • #2
Einternal=Q+W
Q he said is given so +ve and work from the graph is -ve
calculated work was much greateer that's why i think the answer is -ve then wen i tried the numbers i get -1.5 which isn't an answer
 
  • #3
any help?
 
  • #4
You should show your work. But I get the same answer as you do.

[tex]\Delta Q = \Delta U + W[/tex]

where W is the work done by the gas.

That work is the area under the graph. There appears to be an increase in volume of 5 m^3 and a drop in pressure from 7 to 3 atm. So the work done is (7+3)*5/2 = 25 atm-m^3 of work = 2.525e6 Joules.

So:

[tex]\Delta U = \Delta Q - W = 1.02e6 - 2.525e6 = -1.5e6 J[/tex]

AM
 
  • #5
thanks for your help.i will check for any mistakes with the teacher this is cengage and the second mistake already.shame!
 

What is work done during expansion of a gas?

Work done during expansion of a gas refers to the energy that is required to move the gas against an external force, such as a piston, as it expands in volume.

How is work done during expansion of a gas calculated?

The work done during expansion of a gas can be calculated using the equation W = PΔV, where W is the work done, P is the external pressure, and ΔV is the change in volume of the gas.

What is the relationship between work done and expansion of a gas?

The work done during expansion of a gas is directly proportional to the change in volume of the gas. This means that as the gas expands, the work done also increases.

What factors affect the work done during expansion of a gas?

The work done during expansion of a gas is affected by the magnitude of the external pressure, the change in volume of the gas, and the type of gas being expanded.

What is the significance of work done during expansion of a gas?

The work done during expansion of a gas is important in understanding the thermodynamics of gases and their behavior. It is also crucial in various industrial processes, such as in the design of engines and turbines.

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