Types of Disorders  [ENDORSED]


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Clarisse Wikstrom 1H
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Types of Disorders

Postby Clarisse Wikstrom 1H » Mon Feb 05, 2018 8:57 am

When discussing entropy, what's the difference between positional and thermal disorder? (Question 9.85)

Sohini Halder 1G
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Re: Types of Disorders

Postby Sohini Halder 1G » Mon Feb 05, 2018 9:49 am

As you increase volume or mix one substance with another, the molecules of substance X are spread out more, increasing their positional disorder.
As you increase temperature, the thermal motion of the molecules increases.

Lily Guo 1D
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Re: Types of Disorders

Postby Lily Guo 1D » Mon Feb 05, 2018 9:49 am

I think that positional disorder has to do with how much space particles have to move around in. The greater the space, the greater the positional entropy because the more particles can move around. Thermal disorder has to do with temperature, so the higher the temperature, the greater the particle movement and therefore the greater the thermal entropy.

Caroline LaPlaca
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Re: Types of Disorders

Postby Caroline LaPlaca » Mon Feb 05, 2018 9:57 am

increasing temperature increases the motion of the molecules, increasing disorder.

Jasmine Wu 1L
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Re: Types of Disorders

Postby Jasmine Wu 1L » Mon Feb 05, 2018 10:02 am

For question 9.85 part c, the entropy change in the system is due to change in positional disorder, because it is doing from a solid to aqueous state. In the aqueous state, molecules/ions can move more freely as opposed to when they are rigidly packed together in a solid. Thus, entropy is higher in aqueous state. For part d, the entropy change of the surroundings is due to the thermal disorder. The positive enthalpy indicates that heat is absorbed from the surrounding, therefore decreasing temperature and entropy.

Positional disorder is the disorderly locations of the molecules, so it contributes to the entropy (a measurement of the disorder of a system). Thermal disorder is the disorder change coming from the thermal motion of molecules, thus affecting entropy as well.

Katelyn 2E
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Re: Types of Disorders  [ENDORSED]

Postby Katelyn 2E » Mon Feb 05, 2018 10:23 am

Thermal disorder is the disorder arising from the thermal motion of the molecules (heating); an increase in heating supplied/temperature leads to an increase in the disorder of a system because the supply of energy increases the thermal motion of the molecules.
Positional disorder refers to the disorder related to the locations of the molecules (volume); an increase in volume (when a given amount of matter spreads into a greater volume or is mixed with another substance) leads to an increase in the disorder of a system.


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