Textbook Question
Rank each set of substances in order of increasing standard molar entropy (S°). Explain your reasoning. a. NH3(g); Ne(g); SO2(g); CH3CH2OH(g); He(g) c. CH4(g); CF4(g); CCl4(g)
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Ch.18 - Free Energy and Thermodynamics
Chapter 18, Problem 4
A reaction has ΔH°rxn = -112 kJ and ΔS°rxn = 354 J/K. At what temperature is the change in entropy for the reaction equal to the change in entropy for the surroundings?
Verified step by step guidance1
Identify the relationship between the change in entropy for the system (ΔS°_rxn) and the surroundings. The change in entropy for the surroundings (ΔS_surroundings) is given by the formula ΔS_surroundings = -ΔH°_rxn / T.
Set the change in entropy for the system equal to the change in entropy for the surroundings: ΔS°_rxn = -ΔH°_rxn / T.
Rearrange the equation to solve for the temperature (T): T = -ΔH°_rxn / ΔS°_rxn.
Substitute the given values into the equation. Remember to convert ΔH°_rxn from kJ to J by multiplying by 1000, so ΔH°_rxn = -112,000 J.
Calculate the temperature (T) using the rearranged equation with the substituted values.
Related Practice
Textbook Question
Without doing any calculations, determine the sign of ΔSsys for each chemical reaction. a. 2 KClO3(s) → 2 KCl(s) + 3 O2(g) c. Na(s) + 2 Cl2(g) → NaCl(s) d. N2(g) + 3 H2(g) → 2 NH3(g)
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Open Question
What is the molar entropy of a pure crystal at 0 K, and what is the significance of the answer?
Textbook Question
Which of these processes is spontaneous? a. the combustion of natural gas b. the extraction of iron metal from iron ore c. a hot drink cooling to room temperature d. drawing heat energy from the ocean's surface to power a ship
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Textbook Question
Which of these processes are nonspontaneous? Are the nonspontaneous processes impossible? a. a bike going up a hill b. a meteor falling to Earth c. obtaining hydrogen gas from liquid water d. a ball rolling down a hill
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