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### K and Q

Posted: Sun Jan 13, 2019 11:55 pm
What is the difference between K and Q? Why do we need to know the difference?

### Re: K and Q  [ENDORSED]

Posted: Mon Jan 14, 2019 12:01 am
Even though K and Q have the same formula P/R it is the numbers that you plug in that are different. Only once the reaction reaches equilibrium can you plug in for K. But Q is at any point during the reaction. K is only one number, whereas Q can be many different numbers.

### Re: K and Q

Posted: Mon Jan 14, 2019 12:02 am
K is the equilibrium constant and Q is the reaction quotient. K is used when the system is equilibrium and Q is used when the system is not in equilibrium. You can compare K and Q to find out which direction the reaction will proceed.

### Re: K and Q

Posted: Mon Jan 14, 2019 9:22 am
you can find out whether a reaction is at equilibrium using Q if you are given K. Calculate Q, and if the number is equal to K, then the reaction is at equilibrium.

### Re: K and Q

Posted: Mon Jan 14, 2019 9:33 am
Q, the reaction quotient, uses the molar concentrations of the reactants and products at any point during the reaction, while K is the value when the reaction is at equilibrium. If the two values are equal, then the reaction is at equilibrium. If not, then more products or reactant will form so Q can equal K.

### Re: K and Q

Posted: Thu Jan 17, 2019 5:43 pm
If Q, the reaction quotient, is greater than K, then the reaction will favor the reactants but if Q is smaller than K than the reaction will favor the products

### Re: K and Q

Posted: Thu Jan 17, 2019 7:08 pm
Both K and Q use the formula [Products]/[Reactants]. However, K is used only when the reaction is at equilibrium. This means that the concentrations of the products and reactants must be at equilibrium (but not necessarily equal to each other!). Q on the other hand can be found at any time of the reaction.

Q is helpful as it lets us know to which side of the equation the reaction currently "sits" at. For example, if Q > K, then the concentration of products is larger than its concentration at equilibrium because the greater number of products, the greater the value of Q. Conversely, if Q < K, then the concentration of reactants is greater than its concentration at equilibrium because the greater the value of reactants, the smaller the value of Q.

### Re: K and Q

Posted: Thu Jan 17, 2019 9:00 pm
Even though K and Q are calculating the same way, K occurs at equilibrium and we calculate Q in order to know if the reaction is at equilibrium or if it working as a forward or reverse reaction, shifting right or left, respectively.