What is Hess's law, and why does it 'work'?

Video transcript

Hello everyone today we are being given the following problem describe Hess's law and give a reason why it works. So the first thing I'm gonna do is you want to recall what hess's law involves and Hess's law is going to involve was known as the entropy of reactions. And so what is entropy entropy is a state function. And when something is a state function this means that it is independent of the path taken to the final step, meaning the path, it does not matter as long as it goes from start to finish. And so therefore we can conclude that the change in entropy which would be a change in h delta H is going to be equal to the sum. And this is the greek letter for some epsilon it's going to be equal to the sum of entropy changes for each step. And so which answer choice aligns with that D according to his law, the entropy the entropy change of the overall reaction is equal to the sum of the entropy changes for each individual step has his law works because it obeys the law of conservation of energy, meaning if we start with one g of a reactant we will end up with one g of product. And so with that we have answered our question overall. I hope that this helped And until next time