What is a irreversible process?

Question

I can't understand the difference between reversible an irreversible isothermal processes.

Answer 1

First lets deal with the isothermal part, that simply means the process occurs at a constant temperature.

Now a reversible process in thermodynamics means that the rate of entropy (S) is generation is zero. Which means temperature and velocity gradients within the process must be extremely small. An example of a reversible process is gas slowing moving a piston. Another characteristic of a reversible process is that if the surroundings are extracting work from the system, the maximum amount of work is obtained if the process occurs reversibly.

irreversible processes produce a positive change in entropy. An example would be gas expanding through an orifice of an irreversible adiabatic process. (adiabatic means no heat transfer)

I can't think of a irreversible isothermal process example.

Answer 2

the term "isothermal" is not one I have usually used, but I assume that it means processes occuring while you are maintaining a constant temperature. If that's the case, there are some reactions that go to completion at a given temperature and some that occur in equilibrium. You can change the amount of reactants and products at equilibrium by changing other concentrations (and changing pressure if gases are involved) as well as by changing temperature.

Look up LeChatelier's principle for more information on controlling equilibrium conditions.

Answer 3

Reversible is like remelting wax to make a new casting. Irreversible is like boiling an egg, which cannot be made fluid again.

Answer 4

Reversible is that it can be undone, and the person could go back to being how they were before the process.

Irreversible is when there is no way to undo the proceedure, the person is stuck the way that they are after the proceedure is completed.

Answer 5

non- http://pubs.usgs.gov/of/2004/1426/rayinvr/node6.html