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Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium

Chapter 18, Problem 12

Nitrogen reacts with fluorine to form nitrogen trifluoride: Calculate ∆G°, and determine whether the equilibrium composition should favor reactions or products at 25 °C (a) ∆G° = -6.7 kJ; the equilibrium composition should favor products. (b) ∆G° = -332 kJ; the equilibrium composition should favor reactants (c) ∆G° = -166 kJ; the equilibrium composition should favor products (d) ∆G° = +82.6 kJ; the equilbirum composiiton should favor reactants.

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well every once in this video we're talking about the reaction where a plus B yield C. And D. Were given the delta agent reaction and the delta s of reaction. We're being asked here to calculate for my delta G. And predict whether the practice or products are favored at equilibrium at 30 degrees Celsius. So from my formula for delta G of the reaction is equal to delta age of reaction minus T. For temperature multiplied by the delta S of reaction. Let's go ahead and plug in all these values and we do have it already. So that is negative 1 58 killer jewels minus for a temperature. That is 30 degrees Celsius. Of course we want the same kelvin's. So go ahead and add 273.2 15. Then from my delta as a reaction, This is 361 joules per Kelvin, we want to actually convert our jewels into killer jewels so we can do a direct conversion. So for everyone kill a jewel that we have, we have 1000 jewels. So once you put everything into a calculator, we get the value to be negative to 67. units. Of course being killed jules. So then my delta G of the reaction is equal to negative 67.44 killer jewels. That's going to be my first answer for this question. Moving on, we're being asked for the relationship between the Delta G and Cape to see if directors are products are being favorite here. So if my delta G value is less than zero, then my K. Values from G greater than one. It means here that the products our favorite. And if we have a case where my delta G. Is greater than zero, this means that my K. Must be less than one. And what this means is that my reactant, our favorite. Now, what happens if my delta G. Is equal to zero? This means that my, let's get this in format here. This means that my key constant here is equal to one. And what that means is that my reactant and by products are equal. So since my delta G of reaction is less than zero and my K. Is greater than one, my products are being favored. So actually highlight that right over here. So again, in this problem, we're being asked to calculate delta G. So that's this value here and to predict whether the reactors or products are being favored at equilibrium. The products are favored. And this is going to be my final answer for this problem.
Related Practice
Textbook Question
Identify the true statement about a spontaneous process. (a) A reaction that is nonspontaneous in the forward direction is spontaneous in the reverse direction. (b) Adding a catalyst will cause a nonspontaneous reaction to become spontaneous. (c) In a spontaneous process, the entropy of the system always decreases. (d) An endothermic reaction is always spontaneous.
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Textbook Question
Calculate ∆Stotal, and determine whether the reaction is spon-taneous or nonspontaneous under standard-state conditions. (a) -429 J/K; nonspontaneous (b) -123 J/K; spontaneous (c) +3,530 J/K; nonspontaneous (d) +184 J/K; nonspontaneous
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Textbook Question
Consider the following endothermic reaction of gaseous AB3 molecules with A2 molecules.

Identify the true statement about the spontaneity of the reaction. (a) The reaction is likely to be spontaneous at high temperatures. (b) The reaction is likely to be spontaneous at high temperatures. (c) The reaction is always spontaneous. (d) The reaction is always spontaneous.
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Textbook Question
Ammonium hydrogen sulfide, a stink bomb ingredient, decomposes to ammonia and hydrogen sulfide: Calculate the standard free-energy change for the rection at 25 °C if the total pressure resulting from the solid NH4S placed in an evacuated container is 0.658 atm at 25 °C. (a) -43.8 kJ (b) +1.04 kJ (c) -462 kJ (d) +5.51 kJ
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Textbook Question
Consider the following graph of total free energy of reactants and products versus reaction progress for the general reaction, Reactants -> Products. At which of the four points (labeled a, b, c, and d) is Q < K?

(a) Point a (b) Point c and d (c) Point a, c, and d (d) Point b
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Textbook Question

Spinach contains a lot of iron but is not a good source of dietary iron because nearly all the iron is tied up in the oxalate complex [Fe(C2O4)3]3-.

(b) Under the acidic conditions in the stomach, the Fe3+ concentration should be greater because of the reaction

[Fe(C2O4)3]3-(aq) + 6 H3O+(aq) ⇌ Fe3+(aq) + 3 H2C2O4(aq) + 6 H2O(l)

Show, however, that this reaction is nonspontaneous under standard-state conditions. (For H2C2O4, Ka1 = 5.9 × 10-2 and Ka2 = 6.4 × 10-5.)

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