Clarification of terminology

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Alisa Nagashima 1B
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Clarification of terminology

Postby Alisa Nagashima 1B » Fri Jan 08, 2021 5:56 pm

The following phrases are essentially expressing the same idea, right?

If Q < K,
"reaction shifts to the right"
"favors product formation"
"forward reaction is favored"

Also, when K > 103, we say equilibrium lies or sits to the right rather than shifts (used in the module)?
Last edited by Alisa Nagashima 1B on Fri Jan 08, 2021 5:59 pm, edited 1 time in total.

rachelhchem1I
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Re: Clarification of terminology

Postby rachelhchem1I » Fri Jan 08, 2021 5:57 pm

Yes, all three of those statements mean the same thing. And for K, we say it sits/lies because "shift" indicates something other than equilibrium

SophiaJenny3I
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Re: Clarification of terminology

Postby SophiaJenny3I » Fri Jan 08, 2021 6:19 pm

Yes! It all means the same thing. Dr. Lavelle has emphasized however that the equilibrium "shifting" is a misleading description since the equilibrium doesn't shift, it just favors the reactants. But, they're all correct!

Violet Kwan 3H
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Re: Clarification of terminology

Postby Violet Kwan 3H » Fri Jan 08, 2021 6:31 pm

Yes, that is exactly right! And vice versa if Q > K.

kentbui1d
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Re: Clarification of terminology

Postby kentbui1d » Fri Jan 08, 2021 10:40 pm

Yes, they all refer to the same thing, I was also confused about the terms at first!

Jalyn Davis 3D
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Re: Clarification of terminology

Postby Jalyn Davis 3D » Sun Jan 10, 2021 2:21 pm

All three phrases are correct! I also had some trouble with the difference between "lies" and "shifts."

Kristina Krivenko 3I
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Re: Clarification of terminology

Postby Kristina Krivenko 3I » Sun Jan 10, 2021 3:03 pm

Yes, all of the three phrases express the same idea, which is that more products will be formed.

And, as Dr. Lavelle mentioned in the lecture, there may be some confusion with the term "shift," because "shift" typically means "change," but K value is not changing. For this reason, although it is often used in textbooks, Dr. Lavelle prefers using other terms. I just memorized that lie / sit / shift all mean the same thing (that it favors either the reactants or products, depending on the value of K).

Pranav Daggubati 3C
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Re: Clarification of terminology

Postby Pranav Daggubati 3C » Sun Jan 10, 2021 3:21 pm

yes, i think what shifting refers to is when a change occurs in Q, the reaction's equilibrium point has to shift to accommodate it.

Shannon Moore 2L
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Re: Clarification of terminology

Postby Shannon Moore 2L » Sun Jan 10, 2021 7:39 pm

Each of these phrases mean the same thing! However some textbooks/websites will also use the word "shift" in place of these and it means the same thing even though its a slightly misleading term, as Dr. Lavelle said in lecture.

Hasan Mirza 3F
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Re: Clarification of terminology

Postby Hasan Mirza 3F » Sun Jan 10, 2021 7:44 pm

Yes, all three express the same idea.
Its more preferable to say that equilibrium "lies" or "sits" on a side instead of "shifts" because equilibrium won't actually move and its position is entirely based on comparison to other Equilibrium constants.

Uyen Trinh 3C
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Re: Clarification of terminology

Postby Uyen Trinh 3C » Sun Jan 10, 2021 11:02 pm

Using "shifts" can be misleading as it connotes change. Dr. Lavelle clarifies in Lecture 2 that when given a reaction at a specific temperature at equilibrium, the concentration of reactants and products do not change. Thus, equilibriums do not change. However, if you were to compare this reaction to a different reaction with a larger K, then for that reaction you can say the equilibrium lies/sits/shifts more to the right. Here, we mean that K has shifted relative to another reaction.

Emily_Stenzler_2H
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Re: Clarification of terminology

Postby Emily_Stenzler_2H » Sun Jan 10, 2021 11:04 pm

Additionally, he pointed out that equilibrium mixture, equilibrium concentration and equilibrium composition all mean the same thing, just in case anyone was getting confused with those terms as well!

Geethika Janga 1L
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Re: Clarification of terminology

Postby Geethika Janga 1L » Sun Jan 10, 2021 11:06 pm

I was confused about that at first too but yes, all three phrases infer the same thing! When K>10^3, we would use lies or sits rather than shifts because we are equilibrium and the rate of product and reactant formation is constant.

Griffin G
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Re: Clarification of terminology

Postby Griffin G » Mon Jan 11, 2021 3:23 pm

All of that is correct. A lot of those phrases are simply different ways to personify reactions, which makes it easier to comprehend. When K is larger than 1000, there is simply more product than reagent. One could describe this in a plethora of ways, by saying the reaction is product heavy, it sits to the right, etc. etc.

My-Lan Le 1L
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Re: Clarification of terminology

Postby My-Lan Le 1L » Tue Jan 12, 2021 12:21 pm

Yes, they all mean the same thing. But one thing that Professor Lavelle points out explicitly is that all of these phrases should not be taken literally because the reaction is not physically "shifting" or doing other things. Another differentiation to make is the difference between "strongly favoring a reaction" where K has to be less than or equal to 10^3 or -10^-3 and "just favoring" where K is between 10^3 and -10^-3.

Annette Fishman
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Re: Clarification of terminology

Postby Annette Fishman » Tue Jan 12, 2021 12:24 pm

All these phrases mean the same thing. You have to take into consideration too that nothing in the chemical reaction is actually "shifting", that is just simply the terminology.


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