GCSE Chemistry 1 9 Catalysts and Activation Energy

hi guys welcome to this video which is going to be looking at how catalysts affect the rate of reaction and in particular the activation energy of reaction now you should remember from previous video that catalysts speed up the rate of reaction without getting used up what we're going to look at today is how that happens so here I've got graph which is showing me energy against time and as you can see I've got the reactants on the left and the products on the right now this line that I'm drawing up here is called the activation energy which nice and simply is the energy required to actually break the bonds to start the reaction so if use catalyst what it does is it lowers the activation energy you can see here I've drawn line that's lower down which means need less energy for that reaction to occur this means that more of my collisions are successful I'm not increasing the amount of collisions I'm not increasing the speed of the collisions I'm just lowering the energy required making more reactions successful which increases my rates of reaction and that's really all there is to it so I've got two questions let's just see how much of that you've picked up the first one which is knowit which is the absolute basic - this is explain how using catalyst speeds at the rate of reaction talk in terms of activation energy what does it do and then the think it you've got two graphs in front of you which one is more likely to have catalyst added to it granted neither of them or both of them could have had catalyst but out of the two which ones you think is more likely to have had catalyst added and then Weiss was saying explain it so today why you think that pause the video have go and we'll see how it done in minute okay let's have look at the answer then so if we start off with question 1 explain how using catalyst speeds at the rate of reaction nice and simply it lowers the activation energy so that's going to get you first mark and then for the second mark you can say one of two things which is either that less energy is needed to start the reaction or to break the bonds or you can say more collisions are successful if we move on to question 2 so we've got the two graphs so you're gonna get the first mark for saying which one is most likely to add catalyst which is because it's got the lower activation energy and that will be your explanation for it okay that brings this video to an end I've got review question for you which says look at the diagram below annotate it to explain the effect of adding catalyst on the rate of reaction so it's worth three marks so you need to explain what's happening between the reactants and the products and the activation energy thanks for watching guys if you enjoyed the video click on like down below you can have look at the latest video you can visit the website and you can also subscribe if you haven't done so already by now