Chemical Equilibrium - Video Tutorials & Practice Problems

Chemical Equilibrium Concept 1

Hey, guys, in this brand new video, we're going to take a look at the equilibrium state and figure out when exactly do some reactions reach equilibrium? Now, first, we're gonna say that most chemical reactions never go to completion When we say the word completion, all that really means is that our reactant since do not completely convert into products a reaction that goes to completion. Every amount of reactant that's their gets broken down in order to build up to make our products. But we're going to say that this doesn't happen with all chemical reactions, so there's always gonna be some amount of reactant left. Now, that amount could be a very small amount or could be a very large amount. It all depends on the chemical reactions. Now, since are reacting remount is always gonna be some amount. We're gonna say reaction concentrations do not do not go down to zero Now we're going to stay. Instead, these chemical reactions reach a state of chemical equilibrium in which the reaction moves in the forward and the reverse direction. Remember, we talked about this. We see that these reactions have double arrows. One going in the forward one going in the reverse, we're gonna say because they can go in the Ford or the reverse direction, they're called reversible reactions. Here we have a typical reaction. We have reacted a going in the four direction to give us product be and just realize we're going in the four direction here with this forward facing arrow. And we use K one to signify this forward direction. Now, in the same way, the reaction could go in the opposite direction where some of our product actually breaks down itself in order to rebuild some of the reactant that was lost. When we're going in the reverse direction, we use K minus one. The minus signifies that we're going in the reverse direction. Now, if we're gonna look at this plot here, you can see on this plot that are Blue Line represents our reacted A Our red line represents our product be. And what you should take from this chart is this We're gonna be losing reacting, so we lose reactant to make products. So that's the most common theme that we have to take from this image. And what you should realize here is eventually product amount will stop increasing and reacting amount will stop decreasing and they'll reach a plateau for both of them. So they're amounts are gonna be held constant after a while. It's at this five minute mark where they become constant in their concentrations. So we're gonna say equilibrium happens at that exact moment. Okay, so that's how we're able to tell. A reaction has reached chemical equilibrium. The reactant and the product concentrations or amounts have been held constant now reactions air still going on on a molecular level. But for every amount of reacting we lose. It's OK because our products are going in the reverse direction to make up for what we just lost. So in that way, they're leveled. Maintain a same number over time. Okay, so we're gonna say once our amounts plateau, that's when equilibrium is reached. Now, knowing that, I want you guys to take a look at this practice question on the bottom and try your best to answer it on your own. Once you figure out the answer, come back to our next video and click on the explanation. But after answering and see if your answer matches up with my own good luck on this question, guys,

Which one of the following statements does not describe the equilibrium state?

a. While at equilibrium, a dynamic process is still occurring.  

b. The concentration of the reactants is equal to the concentration of the products.

c. The concentration of the reactants and products reach a constant level.

d. At equilibrium, the net concentration of all species is not changing.

e. All are true.

• A. Choice A
• B. Choice B
• C. Choice C
• D. Choice D
• E. Choice E