Tes - CHM2046 Test 4 Version A Answers underlined 1A) How...

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Unformatted text preview: CHM2046 Test 4 Version A Answers underlined 1A) How many electrons are transferred in the following reaction? (balance the equation) 3Mg(s) 6e- + 3Mg 2+ (aq) 2Al 3+ (aq) + 6e- 2Al(s) Net: 3Mg(s) + 2Al 3+ (aq) 2Al(s) + 3Mg 2+ (aq) A) 6 B) 2 C) 3 D) 1 E) 4 2A) The value of K sp for iron(III) hydroxide is 1.1 10 36 at 25 o C. Determine G for in kJ/mol. Fe(OH) 3 (s) Fe 3+ (aq) + 3OH (aq) A) +7.8 10-19 kJ/mol B) -52 kJ/mol C) 1.1 10 36 kJ/mol D) +205 kJ/mol E) -2.0 10 2 kJ/mol G for = -RT ln K = 8.314 J/Kmol 298 K ln (1.1 10 36 ) = (- 8.314 J/Kmol 298 K -82.79775) /1000 J = +205 kJ 3A) What is undergoing reduction in the redox reaction represented by the following cell notation? Fe(s)|Fe 3+ (aq)||Cl 2 (g)|Cl- (aq)|Pt ( reduction on the right, after the ||) Cl 2 + 2e- 2Cl- A) Fe(s) B) 3 Fe (aq) + C) 2 Cl (g) D) Cl (aq) E ) P t 4A) Use the standard half-cell potentials listed below to calculate the standard cell potential for the following reaction occurring in an electrochemical cell at 25C. (The equation is balanced.) 3 2 3Cl (g) 2Fe(s) 6Cl (aq) 2 Fe (aq) + + + 2 Cl (g) 2e 2Cl (aq) + E = +1.36 V 3 Fe (aq) 3e Fe(s) + + E = -0.04 V (written as oxidation in net eqn; reverse direction and sign of E o ; then add to other half eqn) A) +4.16 V B) -1.40 V C) -1.32 V D) +1.32 V E) +1.40 V 3Cl 2 (g) + 6e- 6Cl- E = +1.36 V reduction 2Fe(s) 2Fe 3+ (aq) + 6e- E = +0.04 V oxidation 5A) Calculate G rxn for the reaction below at 25 o C using the data given C 2 H 5 OH( l ) + 3O 2 (g) 2CO 2 (g) + 3H 2 O(g) G f (kJ/mol) -174.9 0 -394.4 -228.6 A) +923.4 kJ B) -1004.2 kJ C)-1299.7 kJ D) -3000.1 kJ E) +2114.2 kJ G rxn = (n G prod ) - (n G react ) = [2(-394.4) + 3(-228.6)]kJ [-174.9 + 0]kJ = -1474.6 kJ + 174.9 kJ = -1299.7 kJ 6A) Determine the redox reaction represented by the following cell notation. Mg(s) |Mg 2+ (aq) ||Cu 2+ (aq) |Cu(s) Mg oxidized, Cu 2+ reduced and eqn must be b a l a n c e d A) 2 2 Cu(s) Mg (aq) Mg(s) Cu (aq) + + + + B) 2 2 Mg(s) Cu (aq) Cu(s) Mg (aq) + + + + C) 2 2 2Mg(s) Cu (aq) Cu(s) 2Mg (aq) + + + + D) 2 2 2Cu(s) Mg (aq) Mg(s) 2Cu (aq) + + + + E) 2 2 3Mg(s) 2Cu (aq) 2Cu(s) 3Mg (aq) + + + + 7A) Determine the equilibrium constant for the following reaction at 298 K....
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Tes - CHM2046 Test 4 Version A Answers underlined 1A) How...

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