The contents of the closed box in each of the following illustrations represent a system, and the arrows show the changes to the system during some process. The lengths of the arrows represent the relative magnitudes of q and w. (a) Which of these processes is endothermic?

Video transcript

Welcome back everyone in this example, we have the boxes below which represents a thermodynamic system. We're told that the arrows pertain to the direction of heat and work that is applied or taken from the system with the length corresponding to their relative magnitudes. We need to identify which of the processes is endo thermic. So our first step is to recall what endo thermic means, and we should recall that for an endo thermic reaction. We have heat being absorbed by our system or reaction. So looking at choice A. Here we have our symbol for heat, which we should recall is represented by Q. So this is heat and we have an arrow going towards the direction of our thermodynamic system here, which is this box. And so because this arrow is going into our system, we would say that according to choice A heat is gained by the system. And sorry, this says system. So before we go ahead and confirm that A is an endo thermic process. Let's go ahead and move onto choice B. Where in choice B. We can see that our value for heat is also shown as going with an arrow in the direction of our system where we also have our variable for work. So this is our variable for work here where we have an arrow going from the surroundings of our system into our system. And this means that work is done on our system or in terms of the prompt work is being applied to the system and we also observed that we still have heat being gained by system. So moving onto choice, see we have now an arrow leaving our system for heat going out to the surroundings. And so we can say that heat is transferred from system to the surroundings, whereas for our symbol for work, we have an arrow for work leaving our system and going outward to the surroundings. And so we would say that work is done by system to the surroundings. So going back to our prompt, we need to just determine which of these processes. A. B or C. Is endo thermic, and that is only in regards to heat. So we don't really need to worry about the variable for work. But as we saw in examples A and B. Our symbol for heat showed an arrow going towards our system, meaning that heat was gained by our system in both cases. And so we would agree that therefore this is an endo thermic process in choice A. Because our system is absorbing heat and therefore Choice B. Is also an endo thermic process. And that means that to complete this example, the correct choices for the processes that are endo thermic would be choices A and choices be which depict our thermodynamic system gaining heat in an endo thermic process. So A and B. Are our final answers. If you have any questions, please leave them down below and I will see everyone in the next practice video