Using data from Appendix 2, calculate ΔS°rxn and ΔSsurr for each of the reactions in Problem 14.11 and determine if each reaction is spontaneous at 25°C.
(a)
Interpretation:
The standard entropy change of the reaction
Concept introduction:
Entropy is the measure of randomness in the system. Standard entropy change in a reaction is the difference in entropy of the products and reactants.
Where,
Standard entropy change in a reaction and entropy change in the system are same. Enthalpy is the amount energy absorbed or released in a process.
The enthalpy change in a system
Where,
Standard enthalpy change in a reaction and entropy change in the system are same.
Using the value for the change in enthalpy in a system and the temperature, we can calculate
The summation of the change in entropy of the system and surroundings will give the value for the change in enthalpy in the universe(
Answer to Problem 14.23QP
The standard entropy of formation,
The entropy of surroundings,
The given reaction is spontaneous
Explanation of Solution
Given,
To calculate
The
To calculate
The
To calculate
To calculate
Since ,
(b)
Interpretation:
The standard entropy change of the reaction
Concept introduction:
Entropy is the measure of randomness in the system. Standard entropy change in a reaction is the difference in entropy of the products and reactants.
Where,
Standard entropy change in a reaction and entropy change in the system are same. Enthalpy is the amount energy absorbed or released in a process.
The enthalpy change in a system
Where,
Standard enthalpy change in a reaction and entropy change in the system are same.
Using the value for the change in enthalpy in a system and the temperature, we can calculate
The summation of the change in entropy of the system and surroundings will give the value for the change in enthalpy in the universe(
Answer to Problem 14.23QP
The standard entropy of formation,
The entropy of surroundings,
The given reaction is non-spontaneous
Explanation of Solution
Given,
To calculate
The
To calculate
The
To calculate
To calculate
Since,
(c)
Interpretation:
The standard entropy change of the reaction
Concept introduction:
Entropy is the measure of randomness in the system. Standard entropy change in a reaction is the difference in entropy of the products and reactants.
Where,
Standard entropy change in a reaction and entropy change in the system are same. Enthalpy is the amount energy absorbed or released in a process.
The enthalpy change in a system
Where,
Standard enthalpy change in a reaction and entropy change in the system are same.
Using the value for the change in enthalpy in a system and the temperature, we can calculate
The summation of the change in entropy of the system and surroundings will give the value for the change in enthalpy in the universe(
Answer to Problem 14.23QP
The standard entropy of formation,
The entropy of surroundings,
The given reaction is nonspontaneous
Explanation of Solution
To record the given data
To calculate
Explanation:
The
To calculate
The
To calculate
To calculate
Since,
(d)
Interpretation:
The standard entropy change of the reaction
Concept introduction:
Entropy is the measure of randomness in the system. Standard entropy change in a reaction is the difference in entropy of the products and reactants.
Where,
Standard entropy change in a reaction and entropy change in the system are same. Enthalpy is the amount energy absorbed or released in a process.
The enthalpy change in a system
Where,
Standard enthalpy change in a reaction and entropy change in the system are same.
Using the value for the change in enthalpy in a system and the temperature, we can calculate
The summation of the change in entropy of the system and surroundings will give the value for the change in enthalpy in the universe(
Answer to Problem 14.23QP
The standard entropy of formation,
The entropy of surroundings,
The given reaction is spontaneous
Explanation of Solution
To record the given data
To calculate
The
To calculate
The
To calculate
To calculate
Since,
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Chapter 14 Solutions
Chemistry: Atoms First
- 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_forwardConsider the reaction of 1 mol H2(g) at 25C and 1 atm with 1 mol Br2(l) at the same temperature and pressure to produce gaseous HBr 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_forwardThe combustion of acetylene, C2H2, is a spontaneous reaction given by the equation 2C2H2(g)+5O2(g)4CO2(g)+2H2O(l) As expected for a combustion, the reaction is exothermic. What is the sign of H? What do you expect for the sign of S? Explain the spontaneity of the reaction in terms of the enthalpy and entropy changes.arrow_forward
- 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_forwardDefine the following: a. spontaneous process b. entropy c. positional probability d. system e. surroundings f. universearrow_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
- Decide whether the following processes will be spontaneous, and why. The why can be general, not specific. a Ice melting at 5C b Ice melting at +5C c KBr(s) dissolving in water d An unplugged refrigerator getting cold e A leaf falling from a tree to the ground f The reaction Li(s)+12F2(g)LiF(s) g The reaction H2O(l)H2(g)+12O2(g)arrow_forwardWhich of the following are spontaneous processes? a A cube of sugar dissolves in a cup of hot tea. b A rusty crowbar turns shiny. c Butane from a lighter burns in air. d A clock pendulum, initially stopped, begins swinging. e Hydrogen and oxygen gases bubble out from a glass of pure water.arrow_forwardThe free energy for a reaction decreases as temperature increases. Explain how this observation is used to determine the sign of either H or S.arrow_forward
- The decomposition of diamond to graphite [C(diamond) C(graphite)] is thermodynamically favored, but occurs slowly at room temperature. a. Use fG values from Appendix L to calculate rG and Keq for the reaction under standard conditions and 298.15 K. b. Use fH and S values from Appendix L to estimate rG and Keq for the reaction at 1000 K. Assume that enthalpy and entropy values are valid at these temperatures. Does heating shift the equilibrium toward the formation of diamond or graphite? c. Why is the formation of diamond favored at high pressures? d. The phase diagram shows that diamond is thermodynamically favored over graphite at 20,000 atmospheres pressure (about 2 GPa) at room temperature. Why is this conversion actually done at much higher temperatures and pressures?arrow_forwardIdentify each of the processes listed as spontaneous or nons-pontaneous. For each nonspontaneous process, describe the corresponding spontaneous process in the opposite direction. (a) A group of cheerleaders builds a human pyramid. (b) Table salt dissolves in water. (c) A cup of cold coffee in a room becomes steaming hot. (d) Water molecules in the air are converted to hydrogen and oxygen gases. (e) A person peels an orange, and you smell it from across the room.arrow_forwardCalculate H and G for the following reactions at 25C, using thermodynamic data from Appendix C; interpret the signs of H and G. a 2PbO(s)+N2(g)2Pb(s)+2NO(g)\ b CS2(l)+2H2O(l)CO2(g)+2H2S(g)arrow_forward
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