Q and K

[Melissa Solis 1H]

Can someone briefly explain how we compare Q and K to determine the direction of the reaction?

[Vince Li 2A]

Q is the same thing as K, except in Q, the reaction has not finished. Let's say that the equilibrium constant (K) for a reaction is 2. If the Q is calculated to be 0.5, in order to reach K, the numerator has to be larger. In terms of the reaction, more products need to be formed to increase the numerator. (Note: the equation for K is always the concentrations of the products over the concentrations of the reactants). On the other hand, if Q is 3, then in order to decrease Q, the denominator needs to increase, meaning that the number of reactants needs to increase.

[Catie Donohue 2K]

Hi! When Q is equal to K, the reaction is at equilibrium and the reaction is not "moving" in either direction. When Q>K, there are more products than what is needed at equilibrium, so the reaction will move in the reverse direction (towards the reactants to make more reactants) to make up for this difference. When Q<K, there are less products than the amount that is needed at equilibrium, so the reaction will move in the forward direction (towards the products) to create more products and bring the solution back to equilibrium.

[Tam Nguyen 2B]

When the reaction quotient (Q) is greater than your equilibrium constant(K), the reaction will favor the reactants. When Q is less than K, the reaction will favor the products. I try to remember it by the way the mouth (>/<) faces in the greater than/less than signs. Whichever way the mouth faces (>) is where the reaction goes.

Also if your Q = K then the reaction is at equilibrium and won't favor either side.

[Nayra Gharpetian 3F]

If Q<K, the reaction will favor the products. If Q>K, the reaction will favor the reactants

[Jarrett Sung 3B]

You find Q and K the same way, by putting the concentrations of products over concentrations of reactants, taking into account the coefficients. If Q > K, the reaction favors the reactants and if Q < K, the reaction favors the products. Also, if Q = K, the reaction is at equilibrium.

[Bella Bursulaya 3G]

If Q < K, then you know the reaction will proceed in the forward direction (towards products) because if Q is less than K, the denominator of Q is larger. Since we know the denominator is the reactants, this means that there are more reactants than there should be at equilibrium. Using the same logic, if Q > K the reaction will proceed in the reverse direction (towards reactants). If Q = K, the reaction is at equilibrium.

[manisha_joseph_1H]

If Q < K, then the forward reaction is favored and therefore the formation of products. This is because if Q < K, the denominator of the reaction quotient becomes larger which means that the concentration of the reactants is increasing. Since the concentration of the reactants is larger than that of the products, the reaction will shift in favor of forming the products. If Q > K, then the reverse reaction is favored and therefore the formation of the reactants. This is because if Q > K, the numerator of the reaction quotient becomes larger which means that the concentration of the products is increasing. Since the concentration of the products is larger than the reactants, the reaction will shift in favor of forming the reactants.

[Adam Bustamante 1I]

When Q is less than K, the reaction will be in the forward direction (favoring the products). If Q is larger than K, the reaction will be in the reverse direction, favoring the reactants.

[Sofia Azmat 1I]

A general rule is that, if Q<K, the reaction will favor the products, and if Q>K, the reaction will favor the reactants. When Q=K, the reaction is at equilibrium

[Julianna_flores3E]

If Q<K then the reaction will favor the products and when Q<K the reaction will favor the reactants.

[Rachel Kwan 1B]

If you want to understand Q and K in the context of delta G, two equations show you their relationship!

You use delta G = deltaGnought + RTlnQ when you aren't at equilibrium (hence Q)

Use deltaGnought = -RTlnK when you are at equilibrium (hence K)

Notice that delta G doesn't appear in the equation at equilibrium

[RitaThomas_3G]

Hey! So if Q<K, then a forward reaction likely occurs, which means products are favored. When Q>K, a reverse reaction likely occurs, which means reactants are favored. If Q=K, the system is at equilibrium.

[Jaden Joodi 3J]

If Q<K, there are more reactants than products. This means that more reactants will become products in order to reach equilibrium.
The opposite is also true.
If Q > K, there are more products than reactants. This means that more products will become reactants in order to reach equilibrium.
If Q=K, then the system is at equilibrium

[Mina Tadros 3L]

If Q>K, then there are more products present than is needed for equilibrium; thus, the reaction will proceed to the reactants until equilibrium is established. If Q<K, then there are more reactants present than is needed for equilibrium to be established; thus, the reaction will proceed towards the products until equilibrium is established. If Q=K, then the reaction is in equilibrium, and neither the products nor reactants are favored. The rate at which products and reactants are forming is equivalent.

[Melis Kasaba 2B]

Q is the reaction quotient and K is the equilibrium constant.

K > Q: reaction will proceed forward, reactants --> products
K < Q: reaction will proceed in reverse direction, products --> reactants
Q = K: system is already at equilibrium

[Simran Bains 2C]

If Q is less than K, then it would proceed in the forward direction, but if Q is larger than K, then it would proceed in the reverse direction.

[Melanie Lin 3E]

Hi! When Q<K, reactants are greater relative to it's proportion at equilibrium, so the reaction will go towards products. It will be the reverse for Q>K.

[Vivian_Le_1L]

If Q<K, there are more reactants than products. The formation of products is favored in the forward reaction, because there is more reactants to make products.
The opposite is also true.
If Q > K, there are more products than reactants. The formation of products is favored in the reverse reaction (favor formation of reactants in forward reaction) because there is now more products to begin with.
If Q=K, then the system is at equilibrium

[Justin Zhang_1A]

If K is greater than Q, then products are favored and the reaction proceeds forwards. If K is less than Q, then the reactants are favored and the reaction likely proceeds in reverse.

[Carolina Gomez 2G]

If Q > K, then the reactions favors the forward reaction (formation of products) and if Q < K the reaction favors the formation of reactants. If Q = K then the reaction is at equilibrium.

[Kyle Dizon 3A]

We learned this back in the first few weeks, but if Q is larger than K, the products would be favored. Having a smaller Q will result in a favor of reactants. If they are equal, they are claimed to be in equilibrium.

[YuditGaribay3J]

I understand what K is for but I still have a hard time understanding what Q is. How do we use it to compare with K?

[AlbertGu_2C]

Q is when the reaction is not necessarily at equilibrium yet. If Q<K, the reaction favors the products. If Q>K, the reaction favors the reactants. If Q=K then the reaction is at equilibrium

[Jack_Pearce_2H]

If Q<K then the reaction will eventually shift to the right in order to establish more production of products. If Q>K then the opposite occurs, the reaction will eventually shift to the left to establish eq. and produce more reactants.

[Neel Sharma 3F]

When Q is less than K the reaction proceeds to the products. When Q is greater than K the reaction proceeds to the reactants. Hope this helps!

[Joanna Huang]

If Q>K, the reaction shifts towards the reactants. If Q<K, the reaction shifts toward the products.

[Gabe_Ek 1G]

Hi! When Q<K, reactants are greater relative to it's proportion at equilibrium, so the reaction will go towards products. It will be the reverse for Q>K.


When Q<K, there are more reactants are and the reaction with shift towards the products. It is the reverse when Q>K.

[Aanya Tanti 3C]

If q>k, the reaction will proceed left towards the reactants. If q<k, the reaction will proceed to the right to make more products.

[Alen Huang 2G]

If Q is greater than K then the reverse direction is favored and if Q is less than K then the forward direction is favored.

[Halle Villalobos 3E]

Hi! If Q<K, the reaction will proceed towards the right to produce more products. If Q>K, the reverse reaction will be favored and more reactants will be produced. I hope this helps!

[Sukhkiran Kaur 3I]

If Q<K, the reaction will favor the products. If Q>K, the reaction will favor the reactants.

[Kareena Patel 1G]

If Q>K the reaction shifts left towards the reactants and if Q<K then the reaction shifts right towards the products.

[Faith Lee 2L]

Both Q and K refer to the ratio of products to reactants; the only difference is that K is the constant when the system is at equilibrium while Q can be used to describe a system at non-equilibrium states. Since systems want to reach equilibrium, we know that if Q < K, then there are too little products compared to reactants and more products will tend to form (forward reaction is favored). Likewise, if Q > K, there are too little reactants compared to products and more reactants will tend to form (reverse reaction is favored). Hope this helps! :)

[Ranen_Chang_2G]

Q and K are ratios of products to reactants. If Q > K, then you have more products than reactants so it favors the reactants. If Q<K, then you have more reactants than products so it favors the products.

[Tiao Tan 3C]

Q and K are both ratios of [products]/[reactants], but K is the ratio at equilibrium.
When Q is less than K the reaction favors to the products. When Q is greater than K the reaction favors to the reactants.

[DPatel_2L]

If Q<K it would favor the products and vice versa.

[Thomas Gimeno]

Q is a representation of the ratio of products over reactants when not at equilibrium, K is a representation of the ratio of products over reactants when at equilibrium. If Q is bigger, that means the there are currently more products then there would be at equilibrium meaning the reactants are favored. If Q is smaller, then that means there are currently more reactants than there would be at equilibrium so the products would be favored.

[Susan Chamling 1F]

K is at equilbrium, so when Q < K it means it favors products while Q > K means it favors reactants.

[Gabe_Ek 1G]

Since K is usually always at equilibrium, when Q<K the reaction moves towards the products and when Q>K it favors the products.

[Rose_Malki_3G]

If Q is larger than K, then the reaction will go in the reverse direction. If K is greater than Q then the reaction will move in the forward direction. And when Q equals K, then that means the reaction has reached equilibrium