CHEM 1010H Study Guide - Midterm Guide: Heat Capacity, Redox, Chemical Kinetics

13. Consider the following reaction at constant P. Use the information here to determine the value of Assurr at 355K. Predict whether or not this reaction will be spontaneous at this temperature. 2N0 02 2N0. AH 114 kJ 2(g) 2(g) A) ASsur 114 kJ/K, reaction is spontaneous B) Assurr +114 kJ/K, reaction is spontaneous C) ASsurr +321 J/K, reaction is spontaneous D) AS sur 321 J/K, reaction is spontaneous E) AS surr +321 J/K, cannot predict whether this reaction is spontaneous without more information 14. Consider a reaction that has a positive AH and a positive AS. Which of the following statements is TRUE? A) This reaction will be spontaneous only at low temperatures B) This reaction will not be spontaneous at any temperatures This reaction will be spontaneous at all temperatures I) This reaction will not be spontaneous at low temperatures It is not possible to determine without more information 15. Place the following in order of decreasing standard molar entropy

Consider the table of thermodynamic parameters shown in the table and the formation of methanol from carbon monoxide and hydrogen at 298K: CO(g) + 2H_2(g) rightarrow CH_3OH(g) What is Delta H degree for this reaction at 298K? +90.7 kJ/mol -90.7 kJ/mol +128.1 kJ/mol -128.2 kJ/mol What is Delta S degree for this reaction at 298K? +90.1 J/mol-K +221 J/mol-K -90.1 J/mol-K -221 J/mol-K -332 J/mol-K Based on the values you found for Delta H degree and Delta S degree above, this reaction is always spontaneous never spontaneous spontaneous only at low temperatures spontaneous only at high temperatures Is this reaction spontaneous (in the forwards direction) under standard conditions at 298K? Yes, because Delta G degree = -25 kJ/mol Yes, because Delta G degree = +25 kJ/mol No, because Delta G degree = -25 kJ/mol Yes, because Delta G degree = -29 kJ/mol No, because Delta G degree = -29 kJ/mol

Given the following thermodynamic data and balanced equation, calculate the standard free energy change (delta G degree) for the reaction at 25 degree C. Also, based on the calculated (delta G degree), is the reaction spontaneous or non- spontaneous at this temperature? [delta G degree = delta H degree - (delta S degree middot T)] CH_4 (g) + 2 O_2 (g) rightarrow CI_2 (g) + 2 H_2 O(I) delta H degree = -806 kJ {delta S degree [CO_2 (g) = 213.6 J/mol middot K]}, {delta S degree [H_2 O(I) = 129.3 J/mol middot K}}, {delta S degree [CH_4 (g) = 186.2 J/mol middot K]}, {delta S degree [O_2 (g) = 205 J/mol middot K]} a) 0.0 kJ: Reaction is at Equilibrium b) 268.6 kJ: Reaction is Non-Spontaneous c) -268.6 kJ: Reaction is Spontaneous d) -806 kJ: Reaction is Spontaneous e) 806 kJ: Reaction is Non-Spontaneous Given the following thermodynamic data and balanced equation, calculate the standard free energy change (delta G degree) for the reaction at 25 degree C. Also, based on the calculated (delta G degree), is the reaction spontaneous or non-spontaneous at this temperature? [delta G degree = delta H degree - (delta S degree middot T)] 2 Mg O(s) rightarrow 2 Mg (s) + O_2 (g) delta H degree = 1203 kJ {delta S degree [Mg (s) = 32.5 J/mol middot K] }, {delta S degree€‚ [O_2 (g) = 205 J/mol middot K]}, {delta S degree [MgO(s) = 26.8 J/mol middot K]} a) 1139 kJ: Reaction is Non-Spontaneous b) -1139 kJ: Reaction is Spontaneous c) 216.4 kJ: Reaction is Non-Spontaneous d) -216.4 kJ: Reaction is Spontaneous e) 472 kJ: Reaction is Non-Spontaneous Ozone in the lower atmosphere is a pollutant that can form by the following reaction involving the oxidation of unburned hydrocarbons. Using the following thermodynamic data at 25 degree C, calculate the standard change in Free Energy (delta G degree) for the following reaction: CH_4(g) + 8O_2(g) rightarrow ’CO_2(g) + 2H_2 O(g) + 4O_3(g) delta G degree = ? {delta G degree [CO_2 (g) = 394.4 kJ/mol]}, (delta G degree [H_2 O(g) = -228.6 kJ/mol]}, {delta G degree [O_3(g) = 163.2 kJ/mol]}, {delta G degree €‚[CH_4 (g) =-50.5 kJ/mol]}, {delta G degree [O_2(g) = 0.0 kJ/mol]} a) -465.0 kJ b) 148.4 kJ c) -114.9 kJ d) 114.9 kJ e) -148.4 kJ