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 always spontaneous, but proceeds faster at temperatures above -13. C The reaction is spontaneous except below 89. "Cut proceeds at a faster rate above 124 °C. Crystallization of a pure compounds spontaneous only be 128. "C conclusions (pick one) (pick one) AN is (pick one) AN is AN IN (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 observations This reaction is always spontaneous, but proceeds faster at temperatures above -13. C The reaction is spontaneous except below 89. "Cut proceeds at a faster rate above 124 °C. Crystallization of a pure compounds spontaneous only be 128. "C conclusions (pick one) (pick one) AN is (pick one) AN is AN IN (pick one) (pick one)

Chemistry for Engineering Students

4th Edition

ISBN:9781337398909

Author:Lawrence S. Brown, Tom Holme

Publisher:Lawrence S. Brown, Tom Holme

Chapter10: Entropy And The Second Law Of Thermodynamics

Section: Chapter Questions

Problem 10.50PAE: For the reaction NO(g)+NO2(g)N2O3(g) , use tabulated thermodynamic data to calculate H and S. Then...

See similar textbooks

Similar questions

The free energy change, G, for a process at constant temperature and pressure is related to Suniv and reflects the spontaneity of the process. How is G related to Suniv? When is a process spontaneous? Nonspontaneous? At equilibrium? G is a composite term composed of H, T, and S. What is the G equation? Give the four possible sign combinations for H and S. What temperatures are required for each sign combination to yield a spontaneous process? If G is positive, what does it say about the reverse process? How does the G = H TS equation reduce when at the melting-point temperature of a solid-to-liquid phase change or at the boiling-point temperature of a liquid-to-gas phase change? What is the sign of G for the solid-to-liquid phase change at temperatures above the freezing point? What is the sign of G for the liquid-to-gas phase change at temperatures below the boiling point?
10.104 (a) When a chemical bond forms, what happens to the entropy of the system? (b) Thermodynamically, what allows any bond formation to occur? (c) What do your answers to parts (a) and (b) suggest must be true about the formation of chemical bonds for the octet rule to hold?
Benzene can be prepared from acetylene. 3C2H2(g)C6H6(g). Determine the equilibrium constant at 25 C and at 850 C. Is the reaction spontaneous at either of these temperatures? Why is all acetylene not found as benzene?
On the basis of your experience, predict which of the following reactions are spontaneous. (a) CO2(s)CO2(g) at 25°C (b) NaCl(s)NaCl(l) at 25°C (c) 2NaCl(s)2Na(s)+Cl2(g) (d) CO2(g)C(s)+O2(g)
Chemists and engineers who design nuclear power plants have to worry about high-temperature reactions because it is possible for water to decompose. (a) Under what conditions does this reaction occur spontaneously? 2H2O(g) 2H2(g) + O2(g) (b) Under conditions where the decomposition of water is spontaneous, do nuclear engineers have to worry about an oxygen/hydrogen explosion? Justify your answer.
For the reaction CH3OH(l)+32O2(g)2H2O(l)+CO2(g) the value of G is 702.2 kJ at 25C. Other data are as follows: Hf (kJ/mol) at 25C S (J/molK) at 25C CH3OH(l) 238.7 126.8 H2O(l) 285.8 70.0 CO2(g) 393.5 213.7 Calculate the standard entropy, S, per mole of O2(g).
A reaction has H298=100 kj/mol and S298=250 J/mol K. Is the reaction spontaneous at room temperature? If not, under what temperature conditions will it become spontaneous?
How does the second law of thermodynamics explain a spontaneous change in a system that becomes more ordered when that process is exothermic?
What types of experiments can be carried out to determine whether a reaction is spontaneous? Does spontaneity have any relationship to the final equilibrium position of a reaction? Explain.
For the reaction NO(g)+NO2(g)N2O3(g) , use tabulated thermodynamic data to calculate H and S. Then use those values to answer the following questions. (a) Is this reaction spontaneous at 25°C? Explain your answer. (b) If the reaction is not spontaneous at 25°C, will it become spontaneous at higher temperatures or lower temperatures? (c) To show that your prediction is accurate, choose a temperature that corresponds to your prediction in part (b) and calculate G . (Assume that both enthalpy and entropy are independent of temperature.)
Many plastic materials are organic polymers that contain carbon and hydrogen. The oxidation of these plastics in air to farm carbon dioxide and water is a spontaneous process; however, plastic materials tend to persist in the environment. Explain.
Limestone is predominantly CaCO3, which can undergo the reaction CaCO3(s)CaO(s)+CO2(g). We know from experience that this reaction is not spontaneous, yet S for the reaction is positive. How can the second law of thermodynamics explain that this reaction is not spontaneous?