Ch.19 - Free Energy & Thermodynamics

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Tro 6th Edition

Ch.19 - Free Energy & Thermodynamics

문제 6

What is ΔS° for the reaction between nitrogen gas and fluorine gas to form nitrogen trifluoride gas, and how can the sign of ΔS° be rationalized?

문제 7

Calculate ΔG°rxn for the reaction: CaCO3(s) → CaO(s) + CO2(g). Use the following reactions and given ΔG°rxn values: Ca(s) + CO2(g) + 1/2 O2(g) → CaCO3(s) ΔG°rxn = -734.4 kJ, 2 Ca(s) + O2(g) → 2 CaO(s) ΔG°rxn = -1206.6 kJ.

문제 27

Which of these processes is spontaneous? a. the combustion of natural gas b. the extraction of iron metal from iron ore c. a hot drink cooling to room temperature d. drawing heat energy from the ocean's surface to power a ship

문제 28

Which of these processes are nonspontaneous? Are the nonspontaneous processes impossible? a. a bike going up a hill b. a meteor falling to Earth c. obtaining hydrogen gas from liquid water d. a ball rolling down a hill

문제 29

Two systems, each composed of two particles represented by circles, have 20 J of total energy. Which system, A or B, has the greater entropy? Why?

문제 30

Two systems, each composed of three particles represented by circles, have 30 J of total energy. How many energetically equivalent ways can you distribute the particles in each system? Which system has greater entropy?

문제 31

Calculate the change in entropy that occurs in the system when 1.50 mol of isopropyl alcohol (C₃H₈O) melts at its melting point (-89.5 °C). See Table 12.9 for heats of fusion.

문제 32

Calculate the change in entropy that occurs in the system when 1.50 mol of diethyl ether (C₄H₁₀O) condenses from a gas to a liquid at its normal boiling point (34.6 °C). See Table 12.7 for heats of vaporization.

문제 35a

Without doing any calculations, determine the sign of ΔS_sys for each chemical reaction. a. 2 KClO₃(s) → 2 KCl(s) + 3 O₂(g) c. Na(s) + 2 Cl₂(g) → NaCl(s) d. N₂(g) + 3 H₂(g) → 2 NH₃(g)

문제 35b

Without doing any calculations, determine the sign of ΔS_sys for each chemical reaction. b. CH₂=CH₂( g) + H₂( g) → CH₃CH₃( g)

문제 40a

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

문제 40c

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. c. C₃H₈(g) + 5 O₂(g) → 3 CO₂(g) + 4 H₂O(g) ΔH°_rxn = -2044 kJ

문제 41d

Calculate ΔS_surrat the indicated temperature for each reaction. d. ΔH°_rxn= +114 kJ; 77 K

문제 43a

Given the values of ΔH°_rxn, ΔS°_rxn, and T, determine ΔS_univ and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) a. ΔH°_rxn = +135 kJ; ΔS°_rxn = -282 J/K; T = 298 K

문제 43c

Given the values of ΔH°_rxn, ΔS°_rxn, and T, determine ΔS_univ and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) c. ΔH°_rxn = -135 kJ; ΔS°_rxn = -282 J>K; T = 298 K

문제 44a

문제 44c

Given the values of ΔH°_rxn, ΔS°_rxn, and T, determine ΔS_univ and predict whether or not each reaction is spontaneous. (Assume that all reactants and products are in their standard states.) c. ΔH°_rxn = +75 kJ; ΔS°_rxn = -127 J/K; T = 298 K

문제 46

Calculate the change in Gibbs free energy for each of the sets of ΔH°_rxn, ΔS°_rxn, and T given in Problem 44. Predict whether or not each reaction is spontaneous at the temperature indicated. (Assume that all reactants and products are in their standard states.)

문제 48

Calculate the free energy change for this reaction at 25 °C. Is the reaction spontaneous? (Assume that all reactants and products are in their standard states.) 2 Ca(s) + O₂( g) → 2 CaO(s) ΔH°_rxn = -1269.8 kJ; ΔS°_rxn = -364.6 J/K

문제 49

Fill in the blanks in the table. Both ΔH and ΔS refer to the system.

문제 50d

Predict the conditions (high temperature, low temperature, all temperatures, or no temperatures) under which each reaction is spontaneous. a. H₂O(g) → H₂O(l) b. CO₂(s) → CO₂(g) c. H₂(g) → 2 H(g) d. 2 NO₂(g) → 2 NO(g) + O₂(g) (endothermic)

문제 51

How does the molar entropy of a substance change with increasing temperature?

문제 53e

For each pair of substances, choose the one that you expect to have the higher standard molar entropy (S°) at 25 °C. Explain your choices. a. CO(g); CO₂(g) b. CH₃OH(l); CH₃OH(g) c. Ar(g); CO₂(g) d. CH₄(g); SiH₄(g) e. NO₂(g); CH₃CH₂CH₃(g) f. NaBr(s); NaBr(aq)

문제 55a

Rank each set of substances in order of increasing standard molar entropy (S°). Explain your reasoning. a. NH₃(g); Ne(g); SO₂(g); CH₃CH₂OH(g); He(g) c. CH₄(g); CF₄(g); CCl₄(g)

문제 55b

Rank each set of substances in order of increasing standard molar entropy (S°). Explain your reasoning. b. H₂O(s); H₂O(l); H₂O(g)

문제 56

Rank each set of substances in order of increasing standard molar entropy (S°). Explain your reasoning. a. I₂(g); F₂(g); Br₂(g); Cl₂(g) b. H₂O(g); H₂O₂(g); H₂S(g) c. C(s, graphite); C(s, diamond); C(s, amorphous)

문제 57

Use data from Appendix IIB to calculate ΔSrxn ° for each of the reactions. In each case, try to rationalize the sign of ΔSrxn ° . a. C2H4(g) + H2(g) → C2H6(g)

문제 57b

Use data from Appendix IIB to calculate ΔS°_rxnfor each of the reactions. In each case, try to rationalize the sign of ΔS°_rxn. b. C(s) + H₂O(g) → CO(g) + H₂(g)

문제 57c

Use data from Appendix IIB to calculate ΔS°_rxnfor each of the reactions. In each case, try to rationalize the sign of ΔS°_rxn. c. CO(g) + H₂O(g) → H₂(g) + CO₂(g)

문제 57d

Use data from Appendix IIB to calculate ΔS°_rxnfor each of the reactions. In each case, try to rationalize the sign of ΔS°_rxn. d. 2 H₂S(g) + 3 O₂(g) → 2 H₂O(l) + 2 SO₂(g)