when it comes to chemical reactions, were gonna say that many of them never go to completion. This means that react ints do not completely convert into products and as a result reacting concentrations do not go down to zero. We're going to say that these types of chemical reactions reach a chemical equilibrium in which the forward and reverse reactions are happening. What this means is, for example, we have three moles of H two gas reacting with one mole of N two gas to produce two moles of ammonia gasses product. What happens is initially all we have are reacting. It's over time those reactions will break down in order to recombine to form this product. We're gonna say moving in this forward direction to make product we have associated with it, our rate constant in the forward direction. When enough time has passed, the products have built up to a sufficient number, it will begin to break down and move in the reverse direction to reform our reactant that has associated with it, the rate of rate constant for the reverse direction. Now, when it comes to the rate constants, they're tied to rate here in our forward rate and our reverse rate, we're gonna say initially again, we only have react ints. So we're gonna start out with our forward rate in which reactant break down to form products. Realize here that over time this forward rate will decrease. That's because we're having less and less reactant that can break down. So the forward rate is slowing down at the same time, we have no reverse rate initially because there's no products, but once our products reach a sufficient amount, it will begin to break down and reform our reactant. When that starts to happen, we start to get a reverse rate over time both of these rates will reach a number in which they are equal when the rates become equal in both the forward and reverse direction. That is when equilibrium is established. Now with equilibrium we have our capital K variable here, which is our equilibrium constant. The equilibrium constant equals your rate constant in the four direction, divided by your rate constant in the reverse direction. It is also equal to products. Overreact ints Now remember in the latter part of chemistry, Jen came when you guys took it. Remember what associated with our equilibrium constant is our equilibrium expression here. We ignore solids and liquids we're gonna have here. NH three the coefficient becomes the power so that's squared Divided by age two Cubed Times and two. So this would represent our equilibrium expression or equilibrium equation. Now, if we had actual values for the products and reactions, we could plug them in and find a numerical value for our equilibrium constant. K. By knowing what that value is, we can determine which side of the equation is favored. Um Is the product side favored meaning that our reaction move more in the forward direction to make more products or is it favored in the reverse direction? Now, if we're gonna talk about that we have to take a look here at these three images. Now in the first image, realize here we have our reactant a Our product B. We start out with some reactant initially no products initially. Over time our reactant break down to form products. Realize here because of that our reactions over time are decreasing while our product is increasing Around the five minute mark. We can see that they're amounts reach a plateau where they stop changing it. Is that that exact moment? At five minutes where equilibrium is established here again, remember K. Equals products overreacting. So that's B over A. at Equilibrium. It looks like B is equal to around eight A. is equal to round one. So Kay here is eight, we're gonna say here when K is more than one or greater than one. That means that the ford direction is favored and products are favored because if your favorite in the forward direction, that means you're moving the forward direction more. So to help make more products in this one here we can see that our reactions are still decreasing. Products are still um reactions are decreasing. Products are increasing. But at the end, when equilibrium is established, we still have more reacting than we do product. So he will say this is around six. It looks like and then be here looks like it's around just over four. So in this situation you can see that your K. is less than one and that means that the reverse direction is more favored and that means your reactant, our favorite. So again, the magnitude for K. Weather, K is equal to or greater than greater than one. It means that products are favored if it's less than one, that means reactions are favored in this last image at five minutes, they both meet at around five. So Kay here equals one, which means that we are at ideal equilibrium. So when K equals one, that's more ideal equilibrium. So it's equal to one. So no direction is favored and products and reactions are both favored. So just realize that when it comes to the equilibrium of a chemical reaction, it's moving both in the forward and reverse direction. Because the rate of the forward direction, the rate of the reverse reaction get to a value that's equal after X. Amount of time. At that moment chemical equilibrium can be established um As we go deeper and deeper into chemical equilibrium, we'll talk about additional topics um such as equilibrium concentrations of reactions and products at the end. Ice charts of course as well as other important topics. But fundamentally remember that equilibrium cannot be established until the rate of the forward and the rate of adverse reactions get to an equal value. Yeah
