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Chemistry the Central Science 13th Edition Custom for Lamar University
- What is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the explosive decomposition of TNT? Use your knowledge of TNT and the chemical equation, particularly the phases, to answer this question. (Thermodynamic data for TNT are not in Appendix G.) 2C7H5N3O6(s) 3N2(g) + 5H2O() + 7C(s) + 7CO(g)arrow_forwardCalculate the standard Gibbs free-energy change when SO3 forms from SO2 and O2 at 298 K. Why is sulfur trioxide an important substance to study? (Hint: What happens when it combines with water?)arrow_forwardWhich contains greater entropy, a quantity of frozen benzene or the same quantity of liquid benzene at the same temperature? Explain in terms of the dispersal of energy in the substance.arrow_forward
- 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.arrow_forwardThe standard molar entropy of methanol vapor, CH3OH(g), is 239.8 J K1 mol-1. (a) Calculate the entropy change for the vaporization of 1 mol methanol (use data from Table 16.1 or Appendix J). (b) Calculate the enthalpy of vaporization of methanol, assuming that rS doesnt depend on temperature and taking the boiling point of methanol to be 64.6C.arrow_forwardConsider the reaction of 2 mol H2(g) at 25C and 1 atm with 1 mol O2(g) at the same temperature and pressure to produce liquid water at these conditions. If this reaction is run in a controlled way to generate work, what is the maximum useful work that can be obtained? How much entropy is produced in this case?arrow_forward
- Describe how the standard entropy of hydrogen gas at 25C can be obtained from heat measurements.arrow_forwardSolid NH4NO3 is placed in a beaker containing water at 25 C. When the solid has completely dissolved, the temperature of the solution is 23.5 C. (a) Was the process exothermic or endothermic? (b) Was the process spontaneous? (c) Did the entropy of the system increase? (d) Did the entropy of the universe increase?arrow_forwardWhat determines Ssurr for a process? To calculate Ssurr at constant pressure and temperature, we use the following equation: Ssurr = H/T. Why does a minus sign appear in the equation, and why is Ssurr inversely proportional to temperature?arrow_forward
- Diethyl ether, (C2H5)2O, was once used as an anesthetic. Calculate the entropy change, rS, for the vaporization of ether if its heat of vaporization is 26.0 kJ/mol at the boiling point of 35.0 C.arrow_forwardWhat is the sign of the standard Gibbs free-energy change at low temperatures and at high temperatures for the combustion of acetaldehyde? CH3CHO(l)+52O2(g)2CO2+2H2O(l)arrow_forwardYeast can produce ethanol by the fermentation of glucose (C6H12O6), which is the basis for the production of most alcoholic beverages. C6H12O6(aq) 2 C2H5OH() + 2 CO2(g) Calculate rH, rS, and rG for the reaction at 25 C. Is the reaction product- or reactant-favored at equilibrium? In addition to the thermodynamic values in Appendix L, you will need the following data for C6H12O6(aq): fH = 1260.0 kl/mol; S = 289 J/K mol; and fG = 918.8 kl/mol.arrow_forward
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