6. (15 points) The following reaction is endothermic: [CoCl2C6H2O] + 6 SOCl2 6 C

Question

6. (15 points) The following reaction is endothermic:

[CoCl2C6H2O] + 6 SOCl2    6    CoCl2 + 12 HCl + 6 SO2 H  > 0

i) (6 pts) The reaction is also spontaneous, at some temperatures. What is the sign ( + or -) of S of the system (S Sys) for this reaction? Explain or show how you decided.

ii) (9 pts) The reaction will be non-spontaneous at low temperatures. Explain why an endothermic reaction becomes non-spontaneous at low temperatures. Your answer must include consideration of the S of the surroundings. You should also remember Clausius’s definition of entropy for this question. (Assume that the numerical values and signs of H Sys and of S Sys do not change with temperature, and that the reaction occurs at constant pressure.)

5. (30 points) A major topic in this course is how to decide whether a reaction or other processwill occur spontaneously. The 2nd Law of Thermodynamics tells us how to decide:“The total entropy of the universe increases in any spontaneous process.” (Gilbert, p.661)
We learned about several ways to decide on spontaneity, but each is actually anapplication of the 2nd Law of Thermodynamics.Listed below are three seemingly different quantities or concepts that can, in principle,allow us to decide whether a system will change spontaneously from its current state to someother, equilibrium state.For each of these, 1) explain how you would, in principle, be able to use it to decidewhether the system will change spontaneously, and, 2) explain how it is consistent with the 2ndLaw of Thermodynamics. Include (at least) one relevant equation in your answers for each part

.a) The number of microstates in the current configuration of an isolated system.

b) Gibbs free energy of a system.

c) The magnitude of Q for a mixture, relative to the value of K.

Answer a) The number of microstates in the current configuration of an isolated system.

Answer b) Gibbs free energy of a system.

Answer c) The magnitude of Q for a mixture, relative to the value of K.

Explanation / Answer

6. (15 points) The following reaction is endothermic:

[CoCl2C6H2O] + 6 SOCl2    6    CoCl2 + 12 HCl + 6 SO2 H  > 0

i) (6 pts) The reaction is also spontaneous, at some temperatures. What is the sign ( + or -) of S of the system (S Sys) for this reaction? Explain or show how you decided.

dG = dH - T*dS

dG < 0, for spontaneous so

dH - T*dS < 0

if dH is positive, then dS must be POSITIVE as well

ii) (9 pts) The reaction will be non-spontaneous at low temperatures. Explain why an endothermic reaction becomes non-spontaneous at low temperatures. Your answer must include consideration of the S of the surroundings. You should also remember Clausius’s definition of entropy for this question. (Assume that the numerical values and signs of H Sys and of S Sys do not change with temperature, and that the reaction occurs at constant pressure.)

From here, dH - T*dS < 0, if dS is too low, then dH > T*dS,

meaning that this will be positiv ein dG value, therefore, favours reverse reaction

The entropy of the surrounding is getting much more negative than that of the system

so the total entropy of the unvierse will be negative, which is not possible

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