Textbook Question
Given the data in Problem 18.78, calculate ∆G for the vaporization of benzene at:
(a) 70 °C
Predict whether benzene will boil at each of these temperatures and 1 atm pressure.
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Ch.18 - Thermodynamics: Entropy, Free Energy & Equilibrium
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McMurry 8th EditionCh.18 - Thermodynamics: Entropy, Free Energy & EquilibriumProblem 98
McMurry 8th EditionCh.18 - Thermodynamics: Entropy, Free Energy & EquilibriumProblem 98Chapter 18, Problem 98
Use the data in Appendix B to tell which of the following compounds are thermodynamically stable with respect to their constituent elements at 25 °C: (a) BaCO3(s) (b) HBr(g) (c) N2O(g) (d) C2H4(g).
Verified step by step guidance1
Step 1: Understand the concept of thermodynamic stability. A compound is thermodynamically stable with respect to its constituent elements if its standard Gibbs free energy of formation (ΔG_f^°) is negative at 25 °C.
Step 2: Locate the standard Gibbs free energy of formation (ΔG_f^°) values for each compound from Appendix B. These values are typically given in units of kJ/mol.
Step 3: For each compound, check the sign of the ΔG_f^° value. If ΔG_f^° is negative, the compound is thermodynamically stable with respect to its constituent elements at 25 °C.
Step 4: Analyze the data for each compound: (a) BaCO3(s), (b) HBr(g), (c) N2O(g), and (d) C2H4(g). Compare their ΔG_f^° values to determine their stability.
Step 5: Conclude which compounds are thermodynamically stable by identifying those with negative ΔG_f^° values.
Related Practice
Open Question
Define (a) the standard free-energy change, ∆G°, for a reaction, and (b) the standard free energy of formation, ∆G°f, of a substance.
Textbook Question
What is meant by the standard state of a substance?
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Open Question
Use the data in Appendix B to determine which of the following compounds are thermodynamically stable with respect to their constituent elements at 25 °C. (a) C6H6(l) (b) NO(g) (c) PH3(g) (d) FeO(s)
Textbook Question
Use the values of of ∆G°f in Appendix B to calculate the stan-dard free-energy change for the synthesis of dichloroethane from ethylene and chlorine:
C2H41g2 + Cl21g2S CH2ClCH2Cl1l2
Is it possible to synthesize dichloroethane from gaseous C2H4 and Cl2, each at 25 °C and 1 atm pressure?
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Textbook Question
Ethanol is manufactured in industry by the hydration of ethylene: Using the data in Appendix B, calculate ∆G° and show that this reaction is spontaneous at 25 °C. Why does this reaction become nonspontaneous at higher temperatures? Estimate the temperature at which the reaction becomes nonspontaneous.
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