# Is the entropy change of the ideal gas equals zero?

• tony_engin
In summary, entropy change in an ideal gas is a measure of its disorder or randomness, calculated by considering changes in temperature, volume, and pressure. The entropy change of an ideal gas is equal to zero when there is no change in these factors, as stated by the Second Law of Thermodynamics. However, it may change if any of these factors change. A zero entropy change in an ideal gas indicates thermodynamic equilibrium, where there is no net exchange of energy or matter. This change in entropy is directly related to the internal energy of the gas, with an increase in internal energy leading to an increase in entropy and a decrease in internal energy leading to a decrease in entropy.
tony_engin
Hi all!
Is the entropy change of the ideal gas equals zero?
And for the second part, is it equal to "Q/T" where Q=200kJ and T=40+273?

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Sorry mate, I failed thermo last semester. :D
Passing it this year though!

It does seem like this forum has too many novices for the experts to handle.

I've moved this thread to the college homework zone.

## 1. What is entropy change in an ideal gas?

Entropy change in an ideal gas is a measure of the disorder or randomness of its molecules. It is calculated by taking into account the change in temperature, volume, and pressure of the gas.

## 2. Why is the entropy change of an ideal gas equal to zero?

This is because an ideal gas follows the laws of thermodynamics, specifically the Second Law which states that in a closed system, the entropy of the system will either remain constant or increase over time. Since an ideal gas does not experience any change in temperature, volume, or pressure, its entropy remains constant and therefore the change in entropy is equal to zero.

## 3. Is the entropy change of an ideal gas always equal to zero?

No, the entropy change of an ideal gas is only equal to zero when there is no change in its temperature, volume, or pressure. If any of these factors change, the entropy will also change accordingly.

## 4. What does a zero entropy change in an ideal gas indicate?

A zero entropy change in an ideal gas indicates that the gas is in a state of thermodynamic equilibrium, where there is no net exchange of energy or matter occurring within the system.

## 5. How does the entropy change of an ideal gas relate to its internal energy?

The entropy change of an ideal gas is directly related to its internal energy. An increase in internal energy leads to an increase in entropy, while a decrease in internal energy leads to a decrease in entropy. This relationship is described by the Second Law of Thermodynamics.

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