(a)
Interpretation:
The standard enthalpy change (ΔH°) for the following reaction should be determined:
Concept introduction:
The standard enthalpy of fusion refers to the amount of heat required to melt 1 mole of a solid at its melting point. In the case of ice, the melting point is 0°C.
(b)
Interpretation:
The standard free change (ΔG°) for the following reaction should be determined
Concept introduction:
The change in the Gibbs free energy, ΔG is a
where,
(c)
Interpretation:
The standard free change (?S°) for the following reaction should be determined:
Concept introduction:
Entropy (S) is a thermodynamic function which measures the disorder or the degree of randomness of a system.
A fusion reaction which involves melting of solid is accompanied by an increase in entropy. The standard molar entropy is expressed as
(d)
Interpretation:
The standard free change (ΔG°) for the following reaction at T = -20 o C should be determined:
Concept introduction:
The change in the Gibbs free energy, ΔG is a thermodynamic function which governs the spontaneity of a chemical reaction. It is the amount of energy required to perform useful work The standard Gibbs free energy
where,
(e)
Interpretation:
The standard free change (ΔG°) for the following reaction at T = 20° C should be determined:
Concept introduction:
The change in the Gibbs free energy, ΔG is a thermodynamic function which governs the spontaneity of a chemical reaction. It is the amount of energy required to perform useful work The standard Gibbs free energy
where,
Want to see the full answer?
Check out a sample textbook solutionChapter 16 Solutions
Chemistry: Principles and Reactions
- Predict the sign of S for each of the following and explain. a. the evaporation of alcohol b. the freezing of water c. compressing an ideal gas at constant temperature d. dissolving NaCl in waterarrow_forwardAt 25 °C, what is the Keq for a reaction where ΔH∘= –9.3 kJ/mol and ΔS∘= 75.5 J/mol·K?arrow_forward4.36) Predict the signs of ΔH, ΔS, and ΔG of the system for the following processes at 1 atm: (a) ammonia melts at -60 C, (b) ammonia melts at -77.7 C, and (c) ammonia melts at -100 C. (The normal melting point of ammonia is -77.7 C.)arrow_forward
- Without doing any calculations, determine the sign of ΔSsysΔSsys for each of the following chemical reactions. Explain whyarrow_forward(a) Is an endothermic reaction more likely to be sponta-neous at higher temperatures or lower temperatures? Explain. (b) The change depicted below occurs at constant pressure. Ex-plain your answers to each of the following: (1) What is the sign of ΔH? (2) What is the sign of ΔS? (3) What is the sign of ΔSₛᵤᵣᵣ?(4) How does the sign of ΔG vary with temperature?arrow_forwardWhich of the following processes are spontaneous:(a) the melting of ice cubes at -10 °C and 1 atm pressure;(b) separating a mixture of N2 and O2 into two separatesamples, one that is pure N2 and one that is pure O2;(c) alignment of iron filings in a magnetic field; (d) thereaction of hydrogen gas with oxygen gas to form watervapor at room temperature; (e) the dissolution of HCl(g) inwater to form concentrated hydrochloric acid?arrow_forward
- A potential chemical reaction at 25.0 °C has a ΔHrxn of 163 kJ and a ΔSrxn of -354.3 J/K. What is the ΔGrxn in kJ.arrow_forward4.36) Predict the sign of ΔH, ΔS, and ΔG of the system for the following processes at 1 atm: (a) ammonia melts at -60 C, (b) ammonia melts at -77.7 C , and (c) ammonia melts at -100 C. (The normal melting point of ammonia is -77.7 C.)arrow_forwardLiquid water vaporizes spontaneously at 25ºC. What is the sign of ΔSuniv? Decide on the relative sizes of ΔSsys and ΔSsurr and give their signs.arrow_forward
- For which set of conditions is the reaction always nonspontaneous? ΔH = + and ΔS = + ΔH = - and ΔS = - ΔH = - and ΔS = + ΔH = + and ΔS = - ΔH = 0 and ΔS = 0arrow_forwardWhen delta G is negative A.enthalpy is negative B. reaction is spontaneous C.rx is at equilibrium D. rx is non-spontaneousarrow_forwardFor a particular reaction, AH = -32 kj and AS = -98 J/K. Assume that AH and aS do not vary with temperature. (a) At what temperature will the reaction have AG = 0? (b) If Tis increased from that in part (a), will the reaction be spontaneous or nonspontaneous?arrow_forward
- Chemistry: Principles and ReactionsChemistryISBN:9781305079373Author:William L. Masterton, Cecile N. HurleyPublisher:Cengage LearningChemistryChemistryISBN:9781305957404Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCostePublisher:Cengage LearningChemistry: An Atoms First ApproachChemistryISBN:9781305079243Author:Steven S. Zumdahl, Susan A. ZumdahlPublisher:Cengage Learning
- General Chemistry - Standalone book (MindTap Cour...ChemistryISBN:9781305580343Author:Steven D. Gammon, Ebbing, Darrell Ebbing, Steven D., Darrell; Gammon, Darrell Ebbing; Steven D. Gammon, Darrell D.; Gammon, Ebbing; Steven D. Gammon; DarrellPublisher:Cengage LearningChemistry for Engineering StudentsChemistryISBN:9781337398909Author:Lawrence S. Brown, Tom HolmePublisher:Cengage Learning