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Second and Third Laws of Thermodynamics

#### Q. Consider the reaction Fe(s) + 2HCl(aq) → FeCl2(s) + H2(g) for which ΔH° = -7.400 kJ and ΔS° = 107.9 J/K at 298.15 K. (1) Calculate the entropy change of the UNIVERSE when 2.375 moles of Fe(s) react under standard conditions at 298.15 K. (2) Is this reaction reactant or product favored under standard conditions? (3) If the reaction is product favored, is it enthalpy favored, entropy favored, or favored by both enthalpy and entropy? If the reaction is reactant favored, choose 'reactant favored'.

Solved • Mar 25, 2020

Second and Third Laws of Thermodynamics

#### Q. Which equation is an expression of the second law of thermodynamics for a spontaneous process? a) ΔS univ = ΔS sys + ΔS surr > 0 b) ΔH univ = ΔH sys + ΔH surr< 0 c) ΔS univ = ΔS sys + ΔS surr = 0 d) ΔS univ = ΔS sys + ΔS surr < 0

Solved • Mar 3, 2020

Second and Third Laws of Thermodynamics

#### Q. Can an argon atom undergo vibrational motion? a) no. b) yes.

Solved • Mar 3, 2020

Second and Third Laws of Thermodynamics

#### Q. Consider the reaction 2C2H6(g) + 7O2(g) → 4CO2(g) + 6H2O(g) for which ΔH° = 2.855x10^3 kJ and ΔS° = 92.70 J/K at 298.15 K. (1) Calculate the entropy change of the UNIVERSE when 1.891 moles of C2H6(g) react under standard conditions at 298.15 K. (2) Is this reaction reactant or product favored under standard conditions? (3) If the reaction is product favored, is it enthalpy favored, entropy favored, or favored by both enthalpy and entropy? If the reaction is reactant favored, choose 'reactant favored'.

Solved • Feb 19, 2020

Second and Third Laws of Thermodynamics

#### Q. Consider the reaction 2CO(g) + 2NO(g) → 2CO2(g) + N2(g) for which ΔH° = -746.6 kJ and ΔS° = -198.0 J/K at 298.15 K. (1) Calculate the entropy change of the UNIVERSE when 1.546 moles of CO(g) react under standard conditions at 298.15 K. (2) Is this reaction reactant or product favored under standard conditions? (3) If the reaction is product favored, is it enthalpy favored, entropy favored, or favored by both enthalpy and entropy? If the reaction is reactant favored choose 'reactant favored'.

Solved • Feb 19, 2020

Second and Third Laws of Thermodynamics

#### Q. If this substance is a perfect crystal at T=0 K, what is the value of S at this temperature?

Solved • Dec 1, 2019

Second and Third Laws of Thermodynamics

#### Q. "Rotational" and "vibrational" motions contribute to the entropy in atomic gases like He and Xe. True. False.

Solved • Dec 1, 2019