Factors Influencing Rates

There are four major factors that directly influence how fast or slow a reaction proceeds. Now here, we're going to say, for reaction to occur, reactive molecules must collide with enough energy. And with this whole idea of energy and collisions, we have collision frequency and successful collisions. Now, collision frequency is the number of molecule collisions per unit of time. And successful collisions are just those energetic collisions resulting in product formation because sometimes molecules may collide together, but they may not do it with the right amount of energy or force, and therefore products will not be made. So if we take a look here, we have molecules that are energized. They're energized and hit each other with enough force, and this results in a successful collision where they're stuck together. If they don't have enough energy, then they're not going to lead to a successful collision. They will not stick together, and eventually they will just bounce off one another. So keep this in mind. These are the fundamental things we need for any successful collision for chemical reaction to proceed, click on the next video and let's go a little bit more in depth in terms of these four factors that have a direct impact on the successful collisions

the four factors that have a direct impact on influencing reaction rates include concentration of reactant surface area of reactant temperature and catalysts. Now here, if we take a look at concentration of reactions first, we're going to say the condition is if we increase the reactant concentrations, what effect does this have on collisions? While increasing the amount of reactant within a mixture means they're gonna be more reactant floating around. This is going to result in increased in collision frequency because since there's more molecules floating around, you have a higher likelihood of them bouncing into each other. This results in an increase in your rate. Now, surface area of reactivates here. You want to have a larger surface area. So we want to increase our surface area. Usually, when we talk about surface area for compounds, we can look at compounds as either being linear or branched. When we say linear, linear compounds have higher surface areas. Here we have hydrocarbon, it's made up of ch three, ch two, ch two, ch three branch means that whereas in linear we just have a straight line of elements together, something that's branched, has a portion of it that's sticking out here. The c street part is a branching group, branching decreases our surface area. So just remember if we can increase the surface area of our reactant, that's gonna cause an increase in our collision frequency which in itself again will cause an increase in our rate. Now temperature, we're gonna say here that increasing, increasing our temperature is going to cause an increase in our collision frequencies. If you think of it in terms of your heating up your mixture, your solution, which has reacting molecules floating around. If you're heating it up, those molecules will absorb that extra external heat source and basically use it to power themselves up. This will cause them to move around with greater energy. If they're moving faster, they can bump into each other even faster. So this is going to cause an increase in collision frequency because there's an increase in collision energy from absorbing the thermal energy. Now we're gonna say, the rule of thumb is if we increase the temperature by just 10°C, this causes a doubling of our rate. So our rate would increase by two x. So increasing temperature increases, collisions, increases the force of collisions because the molecules are moving faster. All of this causes an increase in our rate. Finally, a catalyst, we're going to say the addition of a catalyst. Remember edition of a catalyst causes a decrease in your activation energy and that's a good thing because the lower your activation energy is, the more likely that your reactant can become products. So decreasing our activation energy will cause an increase in successful collisions, which in turn will cause an increase in your rate. So, these are the four factors you need to keep in mind when dealing with reaction rates affecting them can have a big impact on how fast or slow your chemical reaction will proceed

which of the following would cause the rate of a chemical reaction to slow? All right, a increase in temperature of the reactant. Remember, the rule of thumb is if you're increasing the temperature of the reactant, that's always going to cause an increase in your rate, because the molecules will absorb this thermal energy and use it to energize themselves to move faster, hitting each other more often and, with greater force, be increasing concentration of the reactant well. If you're increasing the concentration of reactant, there's more reactions floating around, so they're more likely to hit each other, which increases their chances of successfully colliding together. So this would only increase your rate, not decrease it. See increased surface area of the reactant. Increasing the surface of your area of your reactions always causes an increase in your rate, because there's just more spots where things can connect together. So here this always makes the rate faster. The answer here is increase in volume that the reactions take up. This is the answer. If we think about it, let's say we have a container that's this big, and in it we have some floating molecules. They have to collide in order to successfully combine. But what would happen if I increase the volume of the container? Yeah, while keeping the number of molecules the same, right? No, I'm not. I didn't actually count each dot from the first container, but just think of this visualization. Here. The container is bigger. Are the reactive molecules more likely or less likely to collide together? Now they're less likely because there's so much more space between them. There's a lower chance of them finding each other colliding. And then, hopefully some of those collisions lead to sticking together because, remember, you can collide with each other. That doesn't guarantee you'll stick together. Alright, so here, increasing the volume that the reactions increasing volume that the reactions take up means the increase in the container volume. This does not help reaction rate. It lowers it because reactive molecules are less likely to find each other right. So here only option D would potentially slow down a chemical reaction