# What is the difference between a reversible and irreversible gas expansion?

## What is the difference between a reversible and irreversible gas expansion?

The difference is that one expansion is quasi-static (the reversible one) while the other is spontaneous because of a dramatic change of the external constraints (the irreversible one). In the quasi-static case, you start off indeed in the state where gas pressure equates external pressure.

What is the difference between reversible and irreversible isothermal process?

Isothermal means the temperature does not change during the expansion. Reversible would mean that the system was maintained at equilibrium during the process. So: irreversible AND isothermal process would maintain a constant temperature but not remain at equilibrium.

Is isothermal expansion reversible or irreversible?

reversible
Both isothermal and adiabatic processes sketched on a pV graph (discussed in The First Law of Thermodynamics) are reversible in principle because the system is always at an equilibrium state at any point of the processes and can go forward or backward along the given curves.

### Is an isothermal irreversible expansion of an ideal gas?

In isothermal process, there is no change in temperature so dT will be equal to 0. Hence, change in internal energy ΔU=0.

What is irreversible isothermal expansion?

In case of isothermal irreversible expansion , the gas is allowed to expand slowly , its temperature tends to fall but some of the heat from the surrounding is conducted to the gas , keeping the temperature constant .

Why do reversible and irreversible expansion of gas differ in the work that they do on the surroundings?

The only way to transfer entropy to the surroundings is to transfer heat to the surroundings. This means more heat has to be transferred to the surroundings in an irreversible process than a reversible process. That leave less heat to be converted to work for the irreversible process than the reversible process.

## What is reversible isothermal expansion?

Hence, a reversible isothermal expansion is an infinitely-slow increase in volume at constant temperature. For an ideal gas, whose internal energy U is only a function of temperature, we thus have for the first law of thermodynamics: ΔU=qrev+wrev=0.

What is reversible expansion of ideal gas under isothermal condition the correct option is?

In the case of isothermal process, ΔT is zero. The value of ΔU is also zero from the relation. ΔU=nCVΔT. Thus, for reversible and irreversible expansion for an ideal gas, under isothermal conditions, ΔU=0.

Why the work done in isothermal reversible expansion is more than that of irreversible expansion?

The reason why more work is done in a reversible process than an irreversible process is in an irreversible process entropy is generated within the gas whereas in a reversible process entropy is not generated.

### What is the formula for irreversible isothermal expansion?

B. −wq=nRT[1−P2P1]

Why is reversible expansion better than irreversible expansion?

This is a reversible process because a very small increase in the external pressure would cause the gas to be compressed. To expand the gas irreversibly, we reduce the pressure very quickly. As the gas expands it does work on the surroundings (by moving the piston against the external pressure).

What is isothermal reversible expansion?

## Is the process of isothermal expansion reversible?

Now consider an isothermal expansion against an external pressure which is only dp less that the pressure in the system. To restore the system to the original condition, we could put work back into system and reject heat to surroundings via a quasi-static isothermal compression just as we did following the free expansion. The process is reversible.

What is the difference between reversible and irreversible expansion?

In reversible expansion, the system is at each time at equilibrium. Then, you can draw its trajectory on the graph. However, in irreversible expansion the system goes out of equilibrium. In this case, there is no trajectory that you can draw on a phase diagram!

What is the isothermal expansion of an ideal gas?

Isothermal expansion. In an ideal gas, all the collisions between molecules or atoms are perfectly elastic and no intermolecular force of attraction exists in an ideal gas because of the molecules of an ideal gas move so fast and they are so far away from each other that they do not interact at all.

### What causes the difference between reversible and irreversible work in gas?

This comparison provides compelling evidence that the mechanistic cause of the difference between the reversible- and irreversible work in the irreversible expansion/compression of an ideal gas is the rate-dependent viscous work associated with deforming the gas.