Work done by Reversible vs. Irreversible Reactions

[Hailey Johnson]

Hi, I missed a few minutes of a lecture last week and missed Dr. Lavelle talking about this concept in detail. Can someone please explain to me why a reversible reaction does more work than an irreversible reaction.

[Justin Chu 1G]

Based on my understanding, a reversible reaction always does the max amount of work possible since it would have to be in equilibrium. Also, all real processes are irreversible and these irreversible reactions tend to be much faster but less efficient (do less work).

[Katie Blann 1E]

A reversible process is slower so less of the energy is lost as heat. Where a irreversible process tends to generate more friction and more heat is lost to the surroundings.

[Emma Li 2C]

A reversible process means that the system is at equilibrium, where the pressure of the surroundings and the system are equal. In expansion, a tiny decrease in the surrounding pressure results in a tiny push up by the system on the piston. If expansion continues to occur in very very small steps, we could use an integral to sum up an infinite number of steps, and this would give us the max work possible :)

[Yixin Angela Wang 2H]

Dr. Lavelle gave the example of a piston weighed down by sand. The reversible reaction would occur if the weight was removed, grain by grain, slowly. This way, there wouldn't be energy lost as heat.