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Question 1

Easy: Complete and balance the following redox reaction in acid solution:

Cl2(g) + Br-(aq) → Cl-(aq) + Br2(l)

For the balanced oxidation half-reaction, how many electrons are produced? How many bromide ions are there? (Always use smallest integer coefficients.)

Select one or more:  Explanation

Cl2(g) + Br-(aq) → Cl-(aq) + Br2(l)

2Br- + 2e- Br2(l)

Cl2(g)→2 Cl-(aq)

Cl2(g) + 2Br-(aq) + 2e- → 2Cl-(aq) + Br2(l)

Question 2

How many chlorine molecules are in the balanced equation? Question 3

Medium: Complete and balance the following redox reaction in acid solution:

Cu(s) + NO3-(aq) → NO(g) + Cu2+(aq)

For the balanced reduction half-reaction, how many electrons are needed? How many H+ ions are there?

Select one or more:  Explanation

Cu(s) + NO3-(aq) → NO(g) + Cu2+(aq)

Cu(s) ----> Cu2+(aq)  + 2e-

4H+ +  NO3-(aq) → NO(g)  + 2H2O

Question 4

How many H+ ions are in the balanced equation?

(If the H+ ions are the left side (reactant), write it as a positive number. If they are the right side (product), write it as a negative number.) Question 5

Complete and balance the following redox reaction in acid solution:

MnO4-(aq) + C2H2O4(aq) → Mn2+(aq) + CO2(g)

For the balanced oxidation half-reaction, how many electrons are produced? How many H+ ions are there?

Select one or more:  Question 6

How many H+ ions are in the balanced equation?

(If the H+ ions are the left side (reactant), write it as a positive number. If they are the right side (product), write it as a negative number.) Question 7

Complete and balance the following redox reaction in basic solution:

ClO-(aq) + CrO2-(aq) → Cl-(aq) + CrO42-(aq)

For the balanced oxidation half-reaction, how many electrons are produced? How many OH- ions are there?

Hint given in the general feedback.

Select one or more:  Explanation

Balance the half reaction as if it were in acid. Next neutralize the Hby adding OH-.

Question 8

How many OH- ions are in the balanced equation?

(If the OH- ions are the left side (reactant), write it as a positive number. If they are the right side (product), write it as a negative number.) Question 9

Complete and balance the following redox reaction (using smallest coefficients) in basic solution:

Br2(aq) → Br-(aq) + BrO3-(aq)

First balance the oxidation half-reaction. How many OH- ions are there in this half-reaction?

(If the OH- ions are the left side (reactant), write it as a positive number. If they are the right side (product), write it as a negative number.) Question 10

In the balanced reaction, how many Br- ions, OH- ions, and water moleules are there?

Select one or more:   Question 11

Complete and balance the following redox reaction in basic solution:

H2O2(aq) + N2H4(aq) → N2(g) + H2O(l)

First balance the reduction half-reaction. How many OH- ions are there in this half-reaction?

(If the OH- ions are the left side (reactant), write it as a positive number. If they are the right side (product), write it as a negative number.) Question 12

In the balanced reaction, how many N2 molecules, OH- ions, and water moleules are there?

Select one or more:   Question 13

Calculate Eº from the table of standard potentials (Appendix H p. A-15 (Tro) or Appendix 5 p. A27 (Zumdahl)) for the following reaction:

Zn(s) + Fe2+(aq) → Zn2+ + Fe(s) Question 14

Is the reaction spontaneous as written or spontaneous in the reverse direction under standard conditions?

Select one: Question 15

Calculate Eº for the following reaction:

AgCl(s) + Fe2+(aq) → Ag(s) + Fe3+(aq) + Cl-(aq)

Question 16

Is the reaction spontaneous as written or spontaneous in the reverse direction under standard conditions?

Select one: Question 17

Calculate Eº from for the following reaction:

Br2(l) + 2Cl-(aq) → Cl2(g) + 2Br-(aq) Question 18

Is the reaction spontaneous as written or spontaneous in the reverse direction under standard conditions?

Select one: Question 19

Warmup question Which of the following statements are true about a positive electrode in a half-reaction?

Select one or more:  Question 20

A half-cell that consists of a copper wire in 1.00 M CuNO3 solution is connected by a salt bridge to a half cell containing a 1.00 M X(II) acetate solution and an electrode of metal X. The voltage of the cell is 1.93 V, with metal X as the positive electrode. Calculate the standard reduction potential for the X half-reaction. The standard reduction potential of the copper half-reaction is 0.52 V. (Hint, write the half-reactions and the overall chemical equation for the spontaneous reaction.) Question 21

Calculate ΔGo (in J) for 1 moles of electron(s) in each half-reaction and a standard potential of 0.30 V. Question 22

Calculate ΔGo (in J) for 1 moles of electron(s) in each half-reaction and a standard potential of -0.46 V. Question 23

Calculate Keq for 2 moles of electron(s) in each half-reaction and a standard potential of 0.45 V. Question 24

Calculate Keq for 3 moles of electron(s) in each half-reaction and a standard potential of -0.27 V. Question 25

Calculate the potential for: Zn(s) + Fe2+(aq) → Zn2+(aq) + Fe(s)

when the concentrations of the soluble species are as follows:

[Fe2+] = 0.11 M, [Zn2+] = 0.00097 M

See problem 21, if you don't want to recalculate the standard potential. Question 26

Calculate the potential for: AgCl(s) + Fe2+(aq) → Ag(s) + Fe3+(aq) + Cl-(aq)

when the concentrations of the soluble species are as follows:

[Fe2+] = 0.34 M, [Fe3+] = 0.058 M, and [Cl-] = 0.0021 M.

Question 27

Calculate the potential for: Br2(l) + 2Cl-(aq) → Cl2(g) + 2Br-(aq) Use Eº = -.300 V

when the concentrations of the soluble species are as follows:

[Cl-] = 0.44 M, [Br-] = 6.7x10-3 M, PCl2 = 4.1x10-2 atm 