I was told that a system is at equilibrium when the forward and the reverse reaction are happening at the same rate. I am just a little confused however because equilibrium can happen when the reactants and the products aren't necessarily at the same concentration. And if the concentration of one side is larger, won't more collisions happen and therefore will have a faster reaction rate than on the other side?
Answers
Answer:
Chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal.
LEARNING OBJECTIVES
Recall the relationship between the forward and reverse reaction rates when a reaction is at equilibrium
KEY TAKEAWAYS
Key Points
In a chemical equilibrium, the forward and reverse reactions occur at equal rates, and the concentrations of products and reactants remain constant.
A catalyst speeds up the rate of a chemical reaction, but has no effect upon the equilibrium position for that reaction.
Key Terms
chemical equilibrium: In a chemical reaction, the state in which both reactants and products are present at concentrations that have no further tendency to change with time.
the equilibrium position: The point in a chemical reaction at which the concentrations of reactants and products are no longer changing.
In theory, all chemical reactions are in fact double reactions: for every forward reaction, there is a subsequent reverse reaction. The idea can be illustrated as follows:
reactants
⇌
products
For plenty of reactions, however, the forward reaction is so favored, and the reverse reaction is so negligible, that reactions are written simply in terms of the solid forward arrow,
A
→
B
. However, we will now consider forward/reverse reaction pairs that exist in chemical equilibrium with one another.The Concept of Chemical Equilibrium
In a chemical reaction, chemical equilibrium is the state in which the forward reaction rate and the reverse reaction rate are equal. The result of this equilibrium is that the concentrations of the reactants and the products do not change. However, just because concentrations aren’t changing does not mean that all chemical reaction has ceased. Just the opposite is true; chemical equilibrium is a dynamic state in which reactants are being converted into products at all times, but at the exact rate that products are being converted back into reactants. The result of such a situation is analogous to a bridge between two cities, where the rate of cars going over the bridge in each direction is exactly equal. The result is that the net number of cars on either side of the bridge does not change.