hi everyone, i'm trying to study some chemistry on my own, and i'm trying to learn what a chemical equillibrium is, but i'm finding the concept kind of confusing.
i think that it's when the reactant molecules and the product molecules are still colliding, but the concentrations of the reactants and products are the same. in other words, it's when the reaction is complete.
do i have the right idea? thank you!
I think you are on the right track as long as you understand what "when the concentrations of the reactants and products are the same."
If you have a reaction like
2A + B ==> A2B, the equilibrium is when the RATE of 2A + B to give A2B is the same as the RATE of A2B dissociating to give the 2A + B products. When equilibrium is attained the forward reaction (that's 2A + B to give A2B) is still going on and the reverse reaction (that's A2B ==> 2A + B) is still going on so the concentrations really ARE changing BUT the NET concentration of A, B, and A2B ARE NOT changing BECAUSE 2A + B are producing A2B at the same rate as A2B is producing 2A + B. So it isn't correct to say the concentrations are not changing because the both the forward and the reverse reaction are continuing but the net concentrations are not changing. The idea here is that at equilibrium you have a dynamic (an on-going reaction in both directions) equilibrium and not a static equilibrium. In other words the reactants don't produce A2B and then stop at some appropriate point and the A, B, and C molecules/compounds just sit there and look at each other. They continue to react but as long as the forward and reverse reaction rates are the same then that dynamic (moving) equilibrium keeps the net concentrations of A, B, and A2B the same. Hope this helps clear up any confusion. The concept of chemical dynamic equilibrium is an important concept and if you get that down pat it makes the next concepts easier to understand. I applaud you reaching out to make sure you have it under control.
Perhaps I should add that although the net concentrations of those reactants and products are the same I don't mean ALL of them are the same: i.e., the concentration of A probably will be different than the concentration of B and the concentration of C will be different from those of A an B. Depending upon the actual identity of A, B and C it is possible that one or more could be the same concentration.
thank you! this clears it up a lot!!!
Hi! That's a great question. Chemical equilibrium is actually a state in a chemical reaction where the concentration of reactants and products no longer changes over time. It doesn't mean that the reaction has stopped, but rather that the rates of the forward and reverse reactions are equal.
In a chemical reaction, reactant molecules collide with each other to form product molecules. At the same time, product molecules collide with each other to reform reactant molecules. Initially, the concentration of reactants is higher than the concentration of products. As the reaction progresses, the concentration of products increases, while the concentration of reactants decreases.
Eventually, after numerous collisions, the rates of the forward and reverse reactions become equal. The concentrations of reactants and products reach a constant value, and the system is said to be at equilibrium. It is important to note that the reaction is not complete at equilibrium - it simply means that the concentrations of reactants and products no longer change.
To determine if a chemical reaction has reached equilibrium, you can compare the concentrations or pressures of reactants and products over time. If these values remain constant, it indicates an equilibrium state. Additionally, equilibrium is characterized by the absence of macroscopic change in the properties of the system, such as color, temperature, and pressure.
Understanding chemical equilibrium involves the concept of the equilibrium constant (K). The equilibrium constant is a numerical value that represents the ratio of the concentrations of products to reactants at equilibrium. It helps to determine the extent to which reactants are converted into products in a particular chemical reaction.
To summarize, chemical equilibrium occurs when the concentrations of reactants and products in a reaction no longer change over time. It is important to note that equilibrium does not mean the reaction has stopped. It is a dynamic state where reactant molecules continue to collide and form product molecules, while product molecules collide and form reactant molecules.