# Why Am I Getting the Wrong Answer on My Molar Entropy Calculation?

In summary, the conversation is about a person struggling with a problem on Web Assign and needing help with parts B and C. They explain their attempt at solving part B using an equation and plugging in given values, but are still getting the wrong answer. They mention the suggestion of using C_p instead and the importance of operating at constant pressure. Despite trying this multiple times, they are still having trouble.
Working this thing on Web Assign. I feel like I've been doing everything 100% correct, yet I keep getting the wrong answer.

http://img510.imageshack.us/img510/4488/chemkp0.jpg

Basically, I need help on part B and C

What I did for B, I tried to calculate Delta S by using the equation n Cv ln(T2/T1)
I plugged in Cv given in the problem, used 341 for T2, and 298 for T1. n is One, since its for one mole. And I added the value I get to delta S to S that was given in the problem.

What have I been doing wrong.

Last edited by a moderator:
Maybe you should be plugging in $$C_p$$. The question says that the pressure is 1 atmosphere, even at the higher temperature. Therefore you must be operating at constant pressure and your volume must have increased.

I've tried that multiple times. Thanks, though.

## 1. What is molar entropy in chemistry?

Molar entropy in chemistry is a measure of the randomness or disorder of a substance at the molecular level. It is defined as the amount of energy that is unavailable for work during a chemical reaction or physical change.

## 2. How is molar entropy calculated?

Molar entropy can be calculated using the formula ΔS = Q/T, where ΔS is the change in entropy, Q is the heat absorbed or released during a process, and T is the temperature in Kelvin.

## 3. What is the relationship between molar entropy and temperature?

As temperature increases, the molar entropy of a substance also increases. This is because at higher temperatures, molecules have more kinetic energy and can move around more, increasing the disorder of the system.

## 4. How does molar entropy affect chemical reactions?

Molar entropy plays a crucial role in determining the spontaneity of a chemical reaction. If the molar entropy of the products is greater than the molar entropy of the reactants, the reaction will be spontaneous. This is because the products have a higher disorder, or randomness, which is favored according to the second law of thermodynamics.

## 5. What factors can affect molar entropy?

The molar entropy of a substance is affected by factors such as temperature, pressure, and molecular complexity. Generally, substances with more complex molecular structures have higher molar entropy, as there are more possible arrangements and therefore more disorder. Additionally, changes in state, such as melting or vaporization, can also affect molar entropy.

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