The entropy change for a certain nonspontaneous reaction at 50 °C is 104 J/K. (a) Is the reaction endothermic or exothermic? (b) What is the minimum value of ∆H (in kJ) for the reaction?

Video transcript

Hello everyone today. We have the following problem. A non spontaneous reaction has an entropy of 100 joules per kelvin at 80 degrees Celsius determined if the reaction is eggs, a thermic or endo thermic and calculate the minimum value possible for our delta H. Or our entropy change. So for a reaction to be non spontaneous our gifts, free energy or delta G has to be greater than zero. So if we assume that our gives free energy is greater than zero. The equation for gibbs free energy we can substitute that in here for or as our entropy minus the temperature times the entropy being greater than zero. We don't have the entropy. So what we're gonna do is We're going to have our temperature which was 80°C. However it has to be in terms of Kelvin. So we're just going to add to 73. And then our entropy was said to have a value of 100 jewels per kelvin. We're gonna make that greater than zero continuing this, we're gonna get our envelop or when we saw for entropy we're gonna get our entropy is greater than 35315 jewels. But then we're gonna have to convert this to kill a jewels by using the conversion factor that one killer jewels equal to 10 to the third jewels. And when our units cancel out, we're going to get an entropy change of being greater than 35.32 kg jewels. So in other words our entropy change has to be greater than 35.32 kg jewels going off of this. We see this as a positive value. Our entropy change is greater than zero or it's positive. And because it is greater than zero or positive, this reaction is indo thermic, meaning that heat is being added to the reaction. And with that we have solved the problem overall, I hope this helped, and until next time.