Without doing any calculations, determine the signs of ΔS_sys and ΔS surr for each chemical reaction. In addition, predict under what temperatures (all temperatures, low temperatures, or high temperatures), if any, the reaction is spontaneous. a. C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(g) ΔH°_rxn = -2044 kJ

Video transcript

Hello everyone. Today, we have the following problem without doing any calculations determine the science of our change in entropy of the system and the change of entropy of our surroundings for this chemical reaction in addition, predict under what temperatures if any, the reaction is spontaneous. So from this given the reaction converts six moles of gas, we have this one mole of our propane and we have five moles of oxygen gas and it converts that to seven moles. We have three of carbon dioxide and four of water. So we have increased the number of gas particles thus increasing the disorder of the reaction. And so we can say that our entropy of the system is greater than zero. So we can eliminate choice A, we can eliminate choice D Yeah. For our energy of our surroundings, we were given hour change in envoy of the reaction which was negative 2044 kilojoules. And so this change in our envoy is less than zero, meaning that the reaction is exothermic, meaning that it releases energy. So this will increase the entropy of the surroundings. So our entropy of our surroundings will also be greater than zero. From this, we can choose Andrew C as our answer. But let's see where at what temperatures this reaction will be spontaneous. So from this reaction, we see that we have an exothermic reaction, our change in our entropies are greater than zero. This means that this reaction is spontaneous at all temperatures. And this is because both terms in the equation of Gibbs free energy will favor spontaneity. And that gives her energy is the following. So we have the change in entropy subtracted by the temperature multiplied by the entropy. And so our change to entropy will dramatically increase while our change in entropy will decrease. And so with that, we have concluded that the answer is c overall, I hope I felt. And until next time.