9.33 (a)

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Michelle Dong 1F
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Joined: Fri Sep 29, 2017 7:04 am

9.33 (a)

Postby Michelle Dong 1F » Tue Jan 30, 2018 10:26 pm

Without performing any calculations, predict whether there is an increase or a decrease in entropy for each of the following processes:
(a) Cl2 (g) + H2O (l) --> HCl (aq) + HClO (aq)

The answer says that entropy decreases because there's not as many moles of gas on the right side of the equation. Should we always assume that if something is in its gaseous state, its entropy is greater all the other states, even if there's more moles of aqueous solution than moles of gas?

Janine Chan 2K
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Re: 9.33 (a)

Postby Janine Chan 2K » Tue Jan 30, 2018 10:56 pm

The way I thought about it was that when we first look at the equation, there are 2 mols on the left and 2 mols on the right. However, the reactants side has a mol of gas, which has more entropy than liquids are solids. Aqueous just means it's dissolved in water. A gas would have more entropy than a solution.

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Re: 9.33 (a)

Postby RohanGupta1G » Wed Jan 31, 2018 8:40 am

As jannie had said, gasses do have more entropy and therefore the reactants in this case have more entropy than the products because there are more moles of gas on the reactants side.

Liz White 1K
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Re: 9.33 (a)

Postby Liz White 1K » Wed Jan 31, 2018 2:36 pm

If you think back to how Dr. Lavelle explained it in class, entropy is equal to the amount of disorder. Atoms in a gaseous state have more space to move around and bounce off one another compared to liquid and solid states. Therefore, a greater ability to bounce off of one another allows for more positional disorder, which increases the overall disorder and therefore the entropy. With more room, there's more ability to move around and cause chaos. Hope this helps.

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