Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropyAS.Note: if you have not been given enough information to decide a sign, select the "unknown" option.reactionACobservationsThis reaction is slower below 18. °C thanabove.This reaction is spontaneous only above97. °C.This reaction is always spontaneous, butproceeds faster at temperatures above72. °C.AH isAS isconclusionsAH isAS isAH isAS is✓ (pick one)positivenegativeunknown(pick one)(pick one)(pick one)(pick one)

The sign of enthalpy change for an endothermic reaction is positive and that for an exothermic reaction is negative. The sign of Gibbs' free energy change for a non-spontaneous process is positive and that for a spontaneous process is negative.The expression for Gibbs' free energy change ∆G is given as follows: ∆G=∆H-T∆S Here, ∆H = enthalpy change T = temperature ∆S = entropy changeCriteria of spontaneity: ∆H T∆S ∆G=∆H-T∆S Spontaneity of process + + - Spontaneous only when ∆H<T∆S + - + Always non-spontaneous - - - Spontaneous only when ∆H>T∆S - + - Always spontaneous(a) The first part has information only about the reaction kinetics, i.e. whether it is slow or fast. The kinetic data cannot predict the thermodynamics of a reaction. So the information is insufficient to predict signs of ∆H and ∆S in this case. (b) For the second case, the reaction is spontaneous at a temperature above 97oC. So ∆G must be negative above 97oC. The reaction is proceeding at a higher temperature, that's why it is an endothermic reaction. It is because endothermic reactions are favored at high temperatures. Therefore the enthalpy change is positive for this reaction. Since ∆H is positive for the given reaction, the term T∆S must be positive in order to make ∆G negative for the reaction to be spontaneous. The term T∆S will be positive when ∆S is positive. Hence ∆H and ∆S both will be positive at temperatures above 97oC for the second case.(c) For the third case, the reaction is spontaneous at all temperatures. So ∆G must be negative at all temperatures. The reaction proceeds faster at a temperature above 72oC, that's why it is an endothermic reaction. It is because endothermic reactions are favored at high temperatures. Therefore the enthalpy change is positive for this reaction. Since ∆H is positive for the given reaction, the term T∆S must be positive in order to make ∆G negative for the reaction to be spontaneous. The term T∆S will be positive when ∆S is positive. Hence ∆H and ∆S both will be positive at all temperatures for the third case.Conclusion: ∆H = unknown, ∆S = unknown ∆H = positive, ∆S = positive ∆H = positive, ∆S = positive

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Chemistry

Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A B с observations This reaction is slower below 18. °C than above. This reaction is spontaneous only above 97. °C. This reaction is always spontaneous, but proceeds faster at temperatures above 72. °C. AH is ΔS is conclusions AH is AS is AH is AS is ✓ (pick one) positive negative unknown (pick one) ✓ (pick one) ✓ (pick one) (pick one)

Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A B с observations This reaction is slower below 18. °C than above. This reaction is spontaneous only above 97. °C. This reaction is always spontaneous, but proceeds faster at temperatures above 72. °C. AH is ΔS is conclusions AH is AS is AH is AS is ✓ (pick one) positive negative unknown (pick one) ✓ (pick one) ✓ (pick one) (pick one)

Chemistry

10th Edition

ISBN:9781305957404

Author:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Publisher:Steven S. Zumdahl, Susan A. Zumdahl, Donald J. DeCoste

Chapter1: Chemical Foundations

Section: Chapter Questions

Problem 1RQ: Define and explain the differences between the following terms. a. law and theory b. theory and...

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For a reaction for which ∆H = -142 kJ/mol and ∆S = -178 J/mol･K, which of the following statements is true? A) The reaction is spontaneous above 798 K. B) The reaction is spontaneous below 798 K. C) The reaction will never reach equilibrium. D) The reaction will never be spontaneous.
Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy A.S. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A B observations This reaction is spontaneous except below -38. °C but proceeds at a faster rate above 185. *C. This reaction is endothermic and proceeds slower at temperatures below 36. *C. This reaction is always spontaneous, but proceeds faster at temperatures below -32. °C. conclusions AH is (pick one) ✓ (pick one) ✓ AS is AH is AS is AH is AS is X (pick one) (pick one) ✔ (pick one) ✓ (pick one)
Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A B C to deduce the signs of AH... observations This reaction is endothermic and proceeds slower at temperatures below 14. °C. This reaction is always spontaneous, but proceeds slower at temperatures below 110. °C. This reaction is spontaneous only above -37. °C. ΔΗ is AS is AH is AS is ΔΗ is AS is conclusions X (pick one) (pick one) (pick one) (pick one) (pick one) (pick one) (pick one) positive negative unknown 4 Maria
Try Again Your answer is incorrect. Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A reaction C: Your answer is incorrect. B с observations This reaction is spontaneous except below - 16. °℃ but proceeds at a faster rate above 133. °C. This reaction is always spontaneous, but proceeds slower at temperatures above 23. °C. The reverse of this reaction is always spontaneous but proceeds slower at temperatures below -50. °C. AH is As is conclusions AH is AS is AH is AS is X positive positive ↑ î negative î positive ŵ positive Ś ↑ positive ↑
For the synthesis of nitrogen dioxide, NO2: 2N2(g) + O2(g) 2NO2(g) this reaction has the energy diagram shown. What is the spontaneity of the reaction? Reaction coordinate Enthalpy
A. Predict the sign of AS', if possible, for each of the following reactions. If you cannot predict the sign for any reaction, state why. (2pts each) a) C2H2(g) + 2 H2(g) → C2H6(g) b) N2(g) + O2(g) → 2 NO(g) c) 2 C2H2(g) + 3 Oz(g) → 4 CO(g) +2 H2O(g) d) 2 C(s) + O2(g) → 2 COg) e) N2H4() → N2(g) +2 H20(g) f) C2H;OH() + 3 O2(g) → 2 CO2(g) + 3 H20() g) Pa(s) + 5 O2(g) → PO10(s) h) 2 NaHCO3(s) → NazCO3(s) + H20(g) + CO2(g)
Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A B с observations This reaction is always spontaneous, but proceeds faster at temperatures below 25. °C. This reaction is spontaneous except above 49. °C. The reverse of this reaction is always spontaneous but proceeds faster at temperatures above 93. °C. AH is AS is conclusions AH is AS is AH is AS is X (pick one) (pick one) (pick one) (pick one) (pick one) (pick one) S î ↑ î ↑
Use the observations about each chemical reaction in the table below to decide the sign (positive or negative) of the reaction enthalpy AH and reaction entropy AS. Note: if you have not been given enough information to decide a sign, select the "unknown" option. reaction A B C observations This reaction is spontaneous only above -7. °℃ but proceeds at a faster rate above 23. °C. This reaction is spontaneous except above -46. °C. This reaction is always spontaneous, but proceeds slower at temperatures below 79. °C. ΔΗ AS is AH is AS is conclusions AH is AS is X ✓ (pick one) ↑ positive negative unknown (pick one) (pick one) (pick one) (pick one) S ↑ ↑ ↑
What is the change in Gibb's Free Energy for a reaction that has an enthalpy change of -270.8 kJ/mol and a entropy change of 550.9 J/(mol K) at 44.7 °C? Your Answer: Answer units
Use the observations about each chemical reaction in the table below to decide the sign
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