Le Chatelier's Principle

Moderators: Chem_Mod, Chem_Admin

Lily Mohtashami
Posts: 148
Joined: Wed Sep 30, 2020 9:34 pm

Le Chatelier's Principle

Postby Lily Mohtashami » Sun Jan 10, 2021 9:22 pm

Can someone please explain Le Chatelier's principle completely, I am a little confused?

Ethan Laureano 3H
Posts: 92
Joined: Wed Sep 30, 2020 9:58 pm

Re: Le Chatelier's Principle

Postby Ethan Laureano 3H » Sun Jan 10, 2021 9:29 pm

Le Chatelier's principle states that when a stress is applied to a system at equilibrium, the system would react to mitigate the stress. To visualize it more easily, think of an aquarium tank with a divider in the middle and both sides having equal water. If you fill more water on one side, the water will flow to the other side to level out. Similarly, if you remove water from one side, the water from the other side will flow to replace the missing water. Now think of this in terms of chemical reactions. If concentration rises on one side of the equation, the other side will rise too to combat this stress and straddle towards to equilibrium constant. Hope this makes sense.

Ivan Chen 2H
Posts: 103
Joined: Wed Sep 30, 2020 9:48 pm

Re: Le Chatelier's Principle

Postby Ivan Chen 2H » Sun Jan 10, 2021 9:41 pm

When an reversible reaction at equilibrium encounters a change in condition, the position of equilibrium moves in order to return the reversible reaction to equilibrium, favoring one side of the reaction over the other. If the concentration of one side increases, the reaction would proceed in the forward direction in order to reduce the concentration. If the pressure of the system increases, the reaction would proceed in the direction that would produce fewer molecules. If the temperature increases, the reaction would proceed in the direction that is endothermic in order to reduce the temperature in the system.

Madison Muggeo 3H
Posts: 101
Joined: Wed Sep 30, 2020 9:35 pm

Re: Le Chatelier's Principle

Postby Madison Muggeo 3H » Thu Jan 14, 2021 9:18 pm

The descriptions above are really good, but another description that might help is from one of the UA's. They described the reaction as a balanced scale. When one side dips, the other side rises, and vice versa. The reaction will then move to make sure that the scale is even/level again.

Katie_Dinh_1D
Posts: 46
Joined: Wed Feb 19, 2020 12:18 am
Been upvoted: 1 time

Re: Le Chatelier's Principle

Postby Katie_Dinh_1D » Thu Jan 14, 2021 11:43 pm

To add, it's always helpful to view Le Chatelier's Principle as the reaction's way of minimizing change. Therefore, if we increase the concentration of a reactant, the reaction will form more product as a result to minimize the change. Likewise, if we increase the concentration of the product, the reaction will form more reactant from the product to minimize the change.

Ritika Prasad 1A
Posts: 45
Joined: Mon Jan 04, 2021 11:26 am

Re: Le Chatelier's Principle

Postby Ritika Prasad 1A » Fri Jan 15, 2021 12:05 am

Here's a summary of the shifts that occur due to changes in a reaction according to Le Chatelier's Principle that I think might help from one of the Audio/Visual Topic Videos:
- Add Reactant: More product is formed until original K is attained
- Add Product: More reactant is formed until original K is attained
- Volume Decrease + More moles on reactant side: More products produced
- Volume Decrease + More moles on product side: More reactants produced
- Pressure Increased through Inert Gas: No effect on reaction
- Adding Heat to Endothermic Reaction: Favor Product formation
- Cooling Exothermic Reaction: Favor Product Formation

Anh Trinh 1J
Posts: 149
Joined: Wed Sep 30, 2020 9:55 pm
Been upvoted: 1 time

Re: Le Chatelier's Principle

Postby Anh Trinh 1J » Fri Jan 15, 2021 12:08 am

Adding on to this, Le Chatelier's Principle states that "when a stress is applied to a system in dynamic equilibrium, the equilibrium tends to adjust to minimize the effect of the stress." In other words, when there is an addition or removal of a reactant or product, the reaction will tend to occur in the direction that restores the value of Q to that of the constant K. I like to think that this is similar to the concept of the conjugate seesaw, in that if one goes up, the other other must go down in order for the reaction to be balanced in the end.

Mackenzie Stockton 2H
Posts: 97
Joined: Wed Sep 30, 2020 10:11 pm

Re: Le Chatelier's Principle

Postby Mackenzie Stockton 2H » Fri Jan 15, 2021 11:21 am

Le Chatelier's principle holds that when a change is exerted on a system (like changing the concentration or pressure by changing the volume), the system will respond in a way that will minimize that change and return to "normal"

Example: For the reaction A+ B --> C. Assume this reaction is reversible. If you increase the concentration of A (add more A to the system), the system now has more A that what it would normally have at equilibrium. To return to the "normal" state before the change, the principle holds that the reaction will shift to the right, and use more A so that the concentration approaches normal levels again.

Stephanie Zhang 2K
Posts: 45
Joined: Wed Nov 18, 2020 12:25 am

Re: Le Chatelier's Principle

Postby Stephanie Zhang 2K » Fri Jan 15, 2021 5:54 pm

The general definition is that the system in equilibria minimizes the effects of any change.
If you add a reactant/remove a product, the system will form more product in order to reach the original K. In order to do so, the reactant concentrations will decrease.
If you add a product/ remove a reactant, the system will form more reactant in order to reach the original K. In order to do so, the product concentrations will decrease.
You can also view the change in product/reactant concentration by thinking of it as affecting Q; once you change the concentration, Q will change, and from there you have to figure out how the others will change to get back to K.

Gwirnowski 3B
Posts: 46
Joined: Wed Nov 18, 2020 12:29 am

Re: Le Chatelier's Principle

Postby Gwirnowski 3B » Fri Jan 15, 2021 6:25 pm

The principle is basically that the reaction will do whatever is needs to do to return to a state of equilibrium and stability. When a change occurs in the reaction, whether it be an increase in concentrations of a reactant or a decrease in the volume of a system, the reaction will, well, react in a way that it will return as close as it can to how it was before the change occurred.

Shalyn Kelly 3H
Posts: 84
Joined: Wed Sep 30, 2020 9:55 pm

Re: Le Chatelier's Principle

Postby Shalyn Kelly 3H » Fri Jan 15, 2021 7:35 pm

Hi! Le Chatelier's principle is basically how the system will strive to achieve equilibrium whenever presented with change. I like the post above where the reaction is described as a balanced scale that will want to even itself out again.

Aanya Tanti 3C
Posts: 42
Joined: Wed Nov 25, 2020 12:19 am

Re: Le Chatelier's Principle

Postby Aanya Tanti 3C » Fri Jan 15, 2021 7:40 pm

Le Chatelier's principle states that chemical reactions adjust to minimise the effect of a change, thus returning to equilibrium. For example, if a system is at equilibrium and extra reactant is added (increasing the concentration of reactants), the reactions will shift towards the right (PRODUCT side) and create more product so that original product/reactant ratio is attained and the system is back at equilibrium.

Anastasia Yulo 1C
Posts: 90
Joined: Wed Sep 30, 2020 9:47 pm

Re: Le Chatelier's Principle

Postby Anastasia Yulo 1C » Sat Jan 16, 2021 8:51 am

It helps me to understand Le Chatelier's principle as a way to maintain balance and equilibrium of a reaction. If there are too many products, then the reaction will produce more reactants. The reaction will shift from products and/or reactants depending on the changes that it experiences.

Navdha Sharma 3J
Posts: 101
Joined: Wed Sep 30, 2020 9:46 pm

Re: Le Chatelier's Principle

Postby Navdha Sharma 3J » Sat Jan 16, 2021 10:24 am

Basically Le Chatelier's principle states that when a system experiences a disturbance (such as concentration, temperature, or pressure changes), it will respond to restore a new equilibrium state.

For instance, if there is an increase in the concentration of products, the equilibrium will shift towards increasing the reactants. And if there is an increase in the reactant concentration, then the equilibrium will shift towards the right to increase the product concentration.

Hana Sigsbee 3B
Posts: 97
Joined: Wed Sep 30, 2020 10:00 pm

Re: Le Chatelier's Principle

Postby Hana Sigsbee 3B » Sat Jan 16, 2021 6:40 pm

My little "dumbed down" version of it that I remember it with is essential that if the system is acted on it will compensate for that but doing more of the opposite action to keep the original K value.

Nayra Gharpetian 3F
Posts: 96
Joined: Wed Sep 30, 2020 9:40 pm
Been upvoted: 1 time

Re: Le Chatelier's Principle

Postby Nayra Gharpetian 3F » Sat Jan 16, 2021 6:43 pm

basically it says that if there is a change in the system the chemical reaction will "shift" to go back to equilibrium and minimize the effects of that change

Emily Langie 3L
Posts: 24
Joined: Wed Nov 13, 2019 12:23 am

Re: Le Chatelier's Principle

Postby Emily Langie 3L » Sun Jan 17, 2021 12:38 pm

Le Chatelier's Principle states that chemical reactions will adjust to minimize the effect of changes. So for example if you have the equilibrium expression
A + B <==> (forward and reverse rxn) C + D, and you add more of molecule A, then the amount of B will decrease because more is being used up, and the amounts of products C and D will increase.

DavidTabib 3H
Posts: 91
Joined: Wed Sep 30, 2020 10:06 pm

Re: Le Chatelier's Principle

Postby DavidTabib 3H » Sun Jan 17, 2021 6:01 pm

Le Chatelier's principle describes how a reaction maintains balance and equilibrium, by either shifting toward the reactants or products.

Biona Hui 1G
Posts: 14
Joined: Sun Jan 10, 2021 12:17 am

Re: Le Chatelier's Principle

Postby Biona Hui 1G » Sun Jan 17, 2021 9:08 pm

Le Chatelier's Principle is basically describing how a reaction tries to restore equilibrium after some sort of stress is added. Usually the condition changes, such as temperature is changed, reactant/product is added into the reaction (throwing off equilibrium), and for gases, the volume changes.

305572629
Posts: 86
Joined: Wed Sep 30, 2020 9:41 pm

Re: Le Chatelier's Principle

Postby 305572629 » Sun Jan 17, 2021 9:11 pm

Le Chatelier's principle states that a system at equilibrium reacts in a way/shifts in the direction that minimizes the stress applied to that system.


Return to “Applying Le Chatelier's Principle to Changes in Chemical & Physical Conditions”

Who is online

Users browsing this forum: No registered users and 1 guest