HW09 - REDOX and Electrochemical Cells

Question 13.0 pts

Balance the skeletal equation of hydrazine with chlorate ions, shown below:

N2H4(g) + ClO3-(aq) \longrightarrow NO(g) + Cl-(aq)

The reaction takes place in basic solution. What is the smallest possible integer coefficient of ClO3- in the balanced equation?

  1. 1
  2. 3
  3. 2
  4. 4

Question 23.0 pts

Identify the reducing agent in the reaction in question 1.
  1. ClO3-
  2. Cl-
  3. N2H4
  4. NO

Question 33.0 pts

In the reaction of thiosulfate ion with chlorine gas in an acidic solution, what is the reducing agent?

Cl2(g) + S2O32-(aq) \longrightarrow Cl-(aq) + SO42-(aq)

  1. Cl2
  2. S2O32-
  3. S2+
  4. Cl

Question 43.0 pts

Balance the reaction in question 3 using oxidation and reduction half-reactions. What is the smallest possible integer coefficient of SO42- in the combined balanced equation?

  1. 1
  2. 4
  3. 3
  4. 2

Question 53.0 pts

Balance the following equation between permanganate and formic acid in acid solution:

MnO4–    +    HCOOH    →     Mn2+    +    CO2

Three questions: (1) Which side does water end up on? (2) What is the coefficient for H+ ? (3) What is the coefficient for formic acid (HCOOH)?

  1. right ; 5 ; 5
  2. left ; 2 ; 5
  3. left ; 6 ; 3
  4. right ; 4 ; 2
  5. right ; 6 ; 5

Question 63.0 pts

Chlorate ion in acidic solution will decompose to form chlorine dioxide and chloride ions:

ClO2–     →     ClO2     +     Cl–

All species are aqueous (aq). Balance this reaction and answer these questions: (1) What is the total number of electrons transferred? (2) What is the coefficient for ClO2 ?  (3) Which side of the reaction is H+ and what is it's coefficient?

  1. 5 e– ; 5 ; left 6
  2. 2 e– ; 1 ; left 2
  3. 4 e– ; 2 ; right 2
  4. 4 e– ; 4 ; left 4
  5. 3 e– ; 2 ; right 4
  6. 4 e– ; 3 ; left 2

Question 73.0 pts

Consider the cell reaction represented by the skeletal equation:

Mn(s) + Ti2+(aq) \longrightarrow Mn2+(aq) + Ti(s)

What is the proper cell diagram for this reaction?

  1. Mn2+(aq) | Mn(s) || Ti(s) | Ti2+(aq)
  2. Mn(s) | Mn2+(aq) || Ti2+(aq) | Ti(s)
  3. Ti(s) | Ti2+(aq) || Mn2+(aq) | Mn(s)
  4. Ti2+(aq) | Ti(s) || Mn(s) | Mn2+(aq)

Question 83.0 pts

CopperZincBattery-01.png

In this electrochemical cell, what is the reduction half reaction?

  1. Cu2+(aq) + 2e- \longrightarrow ⟶ Cu(s)
  2. Zn2+(aq) + 2e- \longrightarrow ⟶ Zn(s)
  3. Cu(s) \longrightarrow ⟶ Cu2+(aq) + 2e-
  4. Zn(s) \longrightarrow ⟶ Zn2+(aq) + 2e-

Question 93.0 pts

In a galvanic cell...

  1. oxidation and reduction take place at the same time, but at different electrodes
  2. oxidation takes place at the cathode
  3. electrical energy is used to reverse spontaneous chemical reactions
  4. electrolytes are added to carry electrons between electrodes

Question 103.0 pts

In a working electrochemical cell (a galvanic cell or a battery), the cations in the salt bridge move toward the cathode.

  1. It depends on the charge of the cation.
  2. It is impossible to tell unless we know if the cathode is "+" or "-".
  3. False
  4. True













CH302 · 50520 Principles of Chemistry II


Spring 2023 · © mccord