(a)
Interpretation:
For the formation of
Concept introduction:
Standard free energy change:
Standard free energy change is measured by subtracting the product of temperature and standard entropy change from the standard enthalpy change of a system.
(a)
Answer to Problem 18.104QP
The value of standard enthalpy change of formation
Explanation of Solution
To calculate: The value of
The value of standard enthalpy change of formation
(b)
Interpretation:
For the formation of
Concept introduction:
Standard free energy change:
Standard free energy change is measured by subtracting the product of temperature and standard entropy change from the standard enthalpy change of a system.
(b)
Answer to Problem 18.104QP
The value of standard entropy of formation of
Explanation of Solution
To calculate: The value of standard entropy of formation of
The value of standard entropy of formation of
(c)
Interpretation:
For the formation of
Concept introduction:
Standard free energy change:
Standard free energy change is measured by subtracting the product of temperature and standard entropy change from the standard enthalpy change of a system.
(c)
Answer to Problem 18.104QP
The calculated value of
Explanation of Solution
To compare: The calculated value of
Given reaction and information
Calculate the change in enthalpy and entropy
Calculate the value of
The calculated value of
(d)
Interpretation:
For the formation of
Concept introduction:
Standard free energy change:
Standard free energy change is measured by subtracting the product of temperature and standard entropy change from the standard enthalpy change of a system.
(d)
Answer to Problem 18.104QP
The result obtained by the student is not correct because the value of
Explanation of Solution
To check: The result obtained by the student
The correct equation is given by
The equation used by the student is given below
The result obtained by the student is not correct because the value of
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Chapter 18 Solutions
General Chemistry - Standalone book (MindTap Course List)
- For each of the following processes, identify the systemand the surroundings. Identify those processes that arespontaneous. For each spontaneous process, identify theconstraint that has been removed to enable the process to occur: Ammonium nitrate dissolves in water. Hydrogen and oxygen explode in a closed bomb. A rubber band is rapidly extended by a hangingweight. The gas in a chamber is slowly compressed by aweighted piston. A glass shatters on the floor.arrow_forwardUse the data in Appendix G to calculate the standard entropy change for H2(g) + CuO(s) H2O() + Cu(s)arrow_forwardThe molecular scale pictures below show snapshots of a strong acid at three different instants after it is added to water. Place the three pictures in the correct order so that they show the progress of the spontaneous process that takes place as the acid dissolves in the water. Explain your answer in terms of entropyarrow_forward
- 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.)arrow_forwardCoal is used as a fuel in some electric-generating plants. Coal is a complex material, but for simplicity we may consider it to be a form of carbon. The energy that can be derived from a fuel is sometimes compared with the enthalpy of the combustion reaction: C(s)+O2(g)CO2(g) Calculate the standard enthalpy change for this reaction at 25C. Actually, only a fraction of the heat from this reaction is available to produce electric energy. In electric generating plants, this reaction is used to generate heat for a steam engine, which turns the generator. Basically the steam engine is a type of heat engine in which steam enters the engine at high temperature (Th), work is done, and the steam then exits at a lower temperature (Tl). The maximum fraction, f, of heat available to produce useful energy depends on the difference between these temperatures (expressed in kelvins), f = (Th Tl)/Th. What is the maximum heat energy available for useful work from the combustion of 1.00 mol of C(s) to CO2(g)? (Assume the value of H calculated at 25C for the heat obtained in the generator.) It is possible to consider more efficient ways to obtain useful energy from a fuel. For example, methane can be burned in a fuel cell to generate electricity directly. The maximum useful energy obtained in these cases is the maximum work, which equals the free-energy change. Calculate the standard free-energy change for the combustion of 1.00 mol of C(s) to CO2(g). Compare this value with the maximum obtained with the heat engine described here.arrow_forwardFor each process, tell whether the entropy change of the system is positive or negative. (a) A glassblower heats glass (the system) to its softening temperature. (b) A teaspoon of sugar dissolves in a cup of coffee. (The system consists of both sugar and coffee.) (c) Calcium carbonate precipitates out of water in a cave to form stalactites and stalagmites. (Consider only the calcium carbonate to be the system.)arrow_forward
- Consider 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_forwardWhat is meant by the standard free-energy change G for a reaction? What is meant by the standard free energy of formation Gf of a substance?arrow_forwardDescribe the energy and entropy changes that occur in the following processes, and indicate whether the processes are spontaneous under the conditions stated: a.Lumber becomes a house b.A seed grows into a tree. c.On a hot day, water evaporates from a lake.arrow_forward
- The value of G for the reaction 2C4H10(g)+13O2(g)8CO2(g)+10H2O(l) is 5490. kJ. Use this value and data from Appendix 4 to calculate the standard free energy of formation for C4H 10(g).arrow_forwardDetermine the entropy change for the combustion of gaseous propane, C3H8, under the standard conditions to give gaseous carbon dioxide and water.arrow_forwardDefine the following: a. spontaneous process b. entropy c. positional probability d. system e. surroundings f. universearrow_forward
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