K and Q [ENDORSED]

[Matthew Casillas 1C]

What is the difference between K and Q? Why do we need to know the difference?

[Sheridan Slaterbeck 1J]

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.

[404975170]

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.

[Hedi Zappacosta 1E]

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.

[Laurence Tacderas 1K]

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.

[Charles Gu 1D]

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

[KatelinTanjuaquio 1L]

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.

[kimberlyrose1G]

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.