Video Transcript

Hi, I'm Robin Higgins, and this is what represents heat added in a chemical equation? So, let's have an example of a typical chemical equation that requires heat. How about burning something, that requires heat. Let's pick glucose which has a structure of C6H12O6, and when we burn things we're going to put them in oxygen air, and that goes towards combustion which makes carbon dioxide and water. So, do some quick balancing, and we have our chemical equation. So, we know that if we take sugar, glucose, and put it in oxygen, nothing happens, there is no chemical reaction. And that's because this isn't all you need to make this reaction happen. You need to add heat, you need to add a flame, you need to get it going with energy. So, if we're going to represent heat, we can do a couple of things. One, usually on top of the reaction arrow we can just write heat, and that implies that you heated this in some way before the reaction happened. And another kind of quick way to do it that chemists like to use is a little triangle. So, you can either do both, one or the other, and this just implies that you heated this in some way before it did this reaction. And so another thing that chemists like to do is in other reactions use hv, and this means light. So, if you ever see something like this, and it has hv on here, it means that you had to shine light before this reaction happened. And these are kind of two quick ways that chemists use to show you that some other type of energy was entered into your reaction. I'm Robin Higgins, and this has been how is heat added expressed in a chemical reaction.