## Reaction Direction

Anokhi Patel 2B
Posts: 76
Joined: Fri Aug 09, 2019 12:17 am

### Reaction Direction

How do we determine is the reaction is "left" or "right". And does the direction of the reaction matter if it is composition or decomposition?

MingdaH 3B
Posts: 133
Joined: Thu Jul 11, 2019 12:17 am

### Re: Reaction Direction

The left and right portions are arbitrary, as, given a reversible reaction, you could switch both sides and the left directional reaction would now be the new right directional compound

Nicholas Chin 1G
Posts: 100
Joined: Thu Jul 11, 2019 12:17 am

### Re: Reaction Direction

You determine it by comparing the equilibrium constant (K) with the reaction quotient (Q). If Q is less than K, then there are less products so the reaction is going to the right. If Q is greater than K, then there are more products so the reaction is going to the left. In this case, it doesn't matter what type of reaction it is.

RasikaObla_4I
Posts: 100
Joined: Thu Jul 25, 2019 12:15 am

### Re: Reaction Direction

If Q>K then the reaction moves to the left because the concentration of products is greater than the concentration of reactants so the reaction would move towards the side of the reactants to reach equilibrium. If Q<K, then the reaction moves to the right because the concentration of reactants is greater than the concentration of products so the reaction would move towards the side of the products to reach equilibrium.

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Reaction Direction

I know that K represents the equilibrium constant, but what does Q represent in this situation?

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Reaction Direction

How do you solve for Q in this situation?

Morgan Carrington 2H
Posts: 54
Joined: Wed Nov 14, 2018 12:22 am

### Re: Reaction Direction

005384106 wrote:I know that K represents the equilibrium constant, but what does Q represent in this situation?

In this situation, Q would represent the state of the reaction at a point where equilibrium has not been reached yet. This is why they are asking about which direction the reaction will occur ("left" or "right") because the Q value will determine it.

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Reaction Direction

I am confused with the equilibrium ratio when using molarity values compared to the equilibrium ratio using partial pressure. Can someone please explain this to me. Thank you

Veronica Lu 2H
Posts: 89
Joined: Wed Sep 18, 2019 12:18 am
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### Re: Reaction Direction

When dealing with equilibrium, the reactions are typically reversible meaning that it could be left to right or the other way around

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Reaction Direction

Morgan Carrington 2H wrote:
005384106 wrote:I know that K represents the equilibrium constant, but what does Q represent in this situation?

In this situation, Q would represent the state of the reaction at a point where equilibrium has not been reached yet. This is why they are asking about which direction the reaction will occur ("left" or "right") because the Q value will determine it.

How will I know whether a reaction will occur left or right based on Q?

Jesse Anderson-Ramirez 3I
Posts: 54
Joined: Thu Sep 26, 2019 12:18 am

### Re: Reaction Direction

005384106 wrote:
Morgan Carrington 2H wrote:
005384106 wrote:I know that K represents the equilibrium constant, but what does Q represent in this situation?

In this situation, Q would represent the state of the reaction at a point where equilibrium has not been reached yet. This is why they are asking about which direction the reaction will occur ("left" or "right") because the Q value will determine it.

How will I know whether a reaction will occur left or right based on Q?

If Q>K the reaction will move to the left because the concentration of products is greater than the concentration of reactants. If Q<K the reaction will move to the right because the concentration of reactants is greater than the concentration of products.The reaction will move towards the direction necessary to reach equilibrium.

005384106
Posts: 101
Joined: Sat Aug 24, 2019 12:16 am

### Re: Reaction Direction

What is the reaction quotient, Q? Can you determine it by concentration values or K?

Alan Cornejo 1a
Posts: 98
Joined: Fri Aug 30, 2019 12:15 am

### Re: Reaction Direction

One way to determine if the reaction will proceed right or left is by comparing to equilibrium value to the reaction quotient value. If your reaction quotient (Q) is less than K than your reactants will continue to react and your reaction will proceed to the right towards the products and vice versa, if Q is greater than K then the reaction will favor going left towards the reactants.

Owen-Koetters-4I
Posts: 50
Joined: Fri Sep 28, 2018 12:16 am

### Re: Reaction Direction

Compare Q and K

Gurmukhi Bevli 4G
Posts: 49
Joined: Wed Nov 14, 2018 12:20 am

### Re: Reaction Direction

You can determine them using Q and K, for Q>K, the reaction favors reactants and moves left, for Q<K, it favors products and proceeds to the right.

Nicoli Peiris 1B
Posts: 67
Joined: Wed Sep 30, 2020 10:02 pm

### Re: Reaction Direction

It was mentioned in the modules to compare Q and K. Where Q is the reaction quotient and K is the equilibrium constant.

SahajDole_1C
Posts: 63
Joined: Wed Sep 30, 2020 9:33 pm

### Re: Reaction Direction

If the K value is a huge number, then it is towards products but if it is a small number then it's towards reactants.

Ariel Guan 1H
Posts: 66
Joined: Wed Sep 30, 2020 9:36 pm
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### Re: Reaction Direction

If Q > K then it favors left and if Q < K then it favors right

Gabriel Nitro 1E
Posts: 60
Joined: Wed Sep 30, 2020 9:32 pm
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### Re: Reaction Direction

Hi,

In order to determine the predominant direction of a reaction, it depends on how you phrase it. Whether you are talking about the relative magnitudes of the K value (1) or a response in doing something to perturb the system (2). Note, whether the reaction is a decomposition or synthesis reaction doesn't necessarily tell you much about direction.

(1) If K is large, it favors the products while if K is small, it favors the reactants.

(2) If you do something to disrupt the system (I've listened some scenarios below), you must use Le Chatelier's Principle to determine the direction.
- Increasing/Decreasing the concentrations of reactants/products
- Increasing/Decreasing the volume
- Increasing/Decreasing the partial pressures of reactants/products
- Increasing/Decreasing the temperature

Hope this helps! :)

Kareena Patel 1G
Posts: 62
Joined: Wed Sep 30, 2020 9:58 pm

### Re: Reaction Direction

It depends on what is provided. If K>1 the products are favored. If K<1, the reactants are favored. If the reaction quotient Q is provided then you use both Q and K to determine the direction. If Q<K, it shifts right and reactants are favored. If Q>K, it shifts left and products are favored.

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