Imagine a reaction that results in a change in both volume and temperature:

(b) Has there been an enthalpy change? If so, what is the sign of ∆H? Is the reaction exothermic or endothermic?

Video transcript

hi everyone for this problem it reads consider the process shown below, determine the sign of the entropy of reaction and classify the process as endo thermic or eggs. A thermic, so the two things we want to answer here is the sign of the entropy of the reaction. And we want to classify the process as either endo thermic or eggs. Ah Thermic. So let's take a look at the process. Okay, so we see here that we have a constant pressure of one atmosphere and we see that we're going from a temperature of 320 Kelvin to 370 Kelvin. And so what we can say here is that the temperature is increased at constant pressure. Okay, that's what we're observing. The temperature is increasing at constant pressure and what this means is this is going to lead to a change in entropy. And in simple terms the entropy of a reaction is determined by the net energy change that occurs during the reaction. Okay and so here we see that the Temperature is increasing from 320 Kelvin to 370 Kelvin. And so in terms of whether or not this is endo thermic or eggs. A thermic. Let's go ahead and write down what we know about endo thermic and eggs, a thermic as it relates to heat. So for a process or reaction to be endo thermic, what that means is heat is being absorbed and if he is being absorbed, that means the sign for the change in entropy is going to be positive. However, if a process or reaction is eggs a thermic that means heat is being released and the sign for the change in entropy is negative. Okay, so we'll go ahead and right here that this absorbed and released is representing heat and this is representing the sign for the change in entropy. Okay. So the question asks us to determine the sign and classify the process as endo thermic or eggs a thermic. So because heat is being released here, the process is going to be eggs a thermic because the temperature is increasing. Okay, so we know that this process is eggs a thermic. Alright. And so in terms of the sign for the change of entropy we know this is going to be negative. So it's going to be a value that is less than zero. So out of the answer choices given the answer choice that matches the correct one for this process is going to be answer choice. D The change in entropy is going to be less than zero because the sign is negative and the process is eggs a thermic because the temperature is increased so that is going to lead to a release in heat. Okay, so that is it for this problem. I hope this was helpful