Work to compress a gas (constant external pressure)

[1drdan]

What is the work to compress a gas under constant external pressure?
It seems that it is supposed to be w = -P(ext)delta(V)
This equation is certainly true for expansion of a gas, is it also true for compression?
So if we have two gases, same initial conditions, same delta(v) under compression. One is compressed by 10 atm and the other by 5 atm. They end at the same volume, but have different work done on them?
The observational difference I can see is that the 10 atm compression would occur faster than the 5 atm compression. Is the work really a factor of 2 different?
Or, is work really dependent upon the lower of internal and external pressures, and the books talk about expansion more than compression?

 

[atyy]

Yes, it's the same concept, only the sign of delta(V) changes depending on the situation.

 

[baba89]

I would like to clarify the concept of work in relation to compressing a gas under constant external pressure. The work done in this scenario is indeed given by the equation w = -P(ext)delta(V), where P(ext) is the external pressure and delta(V) is the change in volume of the gas.

This equation is valid for both expansion and compression of a gas, as it takes into account the external pressure acting on the gas. In the scenario described, where two gases with the same initial conditions and change in volume are compressed by different external pressures, the work done on them will be different.

The work done is directly proportional to the external pressure, so the gas compressed at 10 atm will require twice the amount of work compared to the gas compressed at 5 atm. This is because the external pressure is a factor in determining the amount of work done on the gas.

It is also important to note that the speed of compression does not affect the amount of work done on the gas. The work done is solely dependent on the external pressure and the change in volume of the gas.

Overall, the work done to compress a gas under constant external pressure is a factor of the external pressure and is not dependent on the lower of internal and external pressures. The equation mentioned in the content is a valid representation of this concept and applies to both expansion and compression of gases.