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 observations conclusions AH is A This reaction is spontaneous except below -21. °C but proceeds at a slower rate below 159. °C. AS is AH is B This reaction is faster above 140. °C than below. AS is AH is C This reaction is spontaneous only below 61. °C. AS is ✓ (pick one) positive negative unknown LAPIGA UNTU (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 observations conclusions AH is A This reaction is spontaneous except below -21. °C but proceeds at a slower rate below 159. °C. AS is AH is B This reaction is faster above 140. °C than below. AS is AH is C This reaction is spontaneous only below 61. °C. AS is ✓ (pick one) positive negative unknown LAPIGA UNTU (pick one) (pick one) (pick one)

Chemistry: An Atoms First Approach

2nd Edition

ISBN:9781305079243

Author:Steven S. Zumdahl, Susan A. Zumdahl

Publisher:Steven S. Zumdahl, Susan A. Zumdahl

Chapter16: Spontaneity, Entropy, And Free Energy

Section: Chapter Questions

Problem 2RQ: What is the second law of thermodynamics? For any process, there are four possible sign combinations...

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What is the second law of thermodynamics? For any process, there are four possible sign combinations for Ssys and Ssurr. Which sign combination(s) always give a spontaneous process? Which sign combination(s) always give a non-spontaneous process? Which sign combination(s) may or may not give a spontaneous process?
The reaction CO2(g)+H2(g)CO(g)+H2O(g) is not spontaneous at room temperature but becomes spontaneous at a much higher temperature. What can you conclude from this about the signs of H and S , assuming that the enthalpy and entropy changes are not greatly affected by the temperature change? Explain your reasoning.
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