Abeka Chemistry chapter 16
Assign an oxidation number for each element in the following compounds and ions: FeSO₄
+2, +6, -2
Assign an oxidation number for each element in the following compounds and ions: PO₄³⁻
+5, -2
Assign an oxidation number for each element in the following compounds and ions: ClO₄⁻
+7, -2
Choose the stonger reducing agent from the following pair: H₂, Fe
Fe
Which member of the following pair is the stronger reducing agent? Fe or Fe²⁺
Fe
Assign an oxidation number to each element in the following compound or ion. HNO₃
H is +1, N is +5, O is -2
Choose the stonger reducing agent from the following pair: Hg, NO
Hg
Which member of the following pair is the stronger reducing agent? H₂ or SO₄²⁻
H₂
Choose the stronger oxidizing agent from the following pair: H₃O⁺, Fe²⁺
H₃O⁺
During the electrolysis of molten potassium iodide (KI) tell the direction of migration for each ion.
Iodide ions (anions) migrate toward the anode and K⁺ ions (cations) migrate toward the cathode.
What does a negative voltage for a given half-cell indicate about the ease of reduction of the metal ion relative to the hydrogen ion, H⁺?
It is more difficult to reduce than H⁺.
Choose the stonger reducing agent from the following pair: I⁻, Au
I⁻
Which member of the following pair is the stronger reducing agent? Al or K
K
MnO₄⁻(aq) and I⁻(aq) react in basic solution to form MnO₂(s) and IO₃⁻(aq). Use the oxidation number method to write the balanced net ionix equation for this reaction.
Pg 286 chapter review problem #2 letter b
What does a metal's position in an activity series indicate about the chemical properties of that particular metal?
The closer to the top the metal is in the list, the more active the metal is and the stronger a reducing agent the metal is. When two different metals are involved in a redox reaction, the metal higher in the list will be oxidized and give up electrons that will reduce the cation of the less active metal.
What is corrosion?
The deterioration of metals caused by electrochemical processes.
Aluminum metal reacts with hydrochloric acid to form aluminum chloride and hydrogen gas: 2 Al(s) + 6 HCl(g)→2AlCl₃(aq) + 3 H₂ (g) which element undergoes oxidation?
aluminum
What is a redox reaction?
an oxidation-reduction reaction--one involving a transfer of electrons
Write the half reactions for the electrolysis of molten potassium iodide (KI). Write the net reaction.
cathode: 2K⁺ + 2e⁻ → 2K anode: 2 I⁻ → I₂ + 2 e⁻ net: 2 I⁻ +2 K⁺ → I₂ + 2 K
What constitutes an electric current?
the flow of electric charge, whether as electrons or ions
What is electrolysis?
the use of an electric current to cause a nonspontaneous redox reaction
Copper metal reacts with bromine in basic solution to produce insoluble copper (I) oxide, bromide ion, and water. Write a balanced equation for this redox reaction.
2 Cu + Br₂ + 2 OH⁻→Cu₂O + 2 Br⁻ + H₂O
Assign an oxidation number for each element in the following compounds and ions: Al₂O₃
=3, -2
What is a voltaic cell?
A device that converts the chamical potential energy of a spontaneous redox chemical reaction into electric energy.
How might you perform an experiment to determine whether Na or Fe (metals) is more active?
Answers will vary. Some ideas: Place a strip of Fe in a Na⁺ salt solution such as NaCl (aq); if no reaction occurs, Na is more active. (You cannot use Na metal in water since they react.)
How might you perform an experiment to determine whether Ag or Zn (metals) is more active?
Answers will vary. Some ideas: Place strips of Ag and Zn in separate beakers containing Zn²⁺ or Ag⁺ ions, respectively. If Zn²⁺ reacts with Ag, Ag is more active; and if Ag⁺ reacts with Zn, Zn is more active.
How might you perform an experiment to determine whether Cu or Hg (metals) is more active?
Answers will vary. Some ideas: Place strips of Cu in Hg₂²⁺ salt solution; if no reaction, Hg is more active. Or place drops of Hg in Cu²⁺ salt solution; if no reaction, Cu is more active than Hg.
If the values of E° for the nickel, copper, gold, and hydrogen half-cells are -0.25 V, +0.34 V, +1.50 V, and 0.0V, respectively, arrange these half-cells in order of decreasing ability to be reduced (beginning with the most easily reduced).
Au, Cu, H₂, Ni
Choose the stronger oxidizing agent from the following pair: I₂, Au³⁺
Au³⁺
Assign an oxidation number to each element in the following compound or ion. CO₂
C is +4, O is -2
Choose the stonger reducing agent from the following pair: Ca, Mg
Ca
Assign an oxidation number to each element in the following compound or ion. CrO₄²⁻
Cr is +6, O is -2
Distinguish between electric current in a metal and electric current in an electrolyte solution.
Electric current in metals consists of a flow of electrons, whereas electric current in an electrolyte consists of a flow of ions.
Choose the stronger oxidizing agent from the following pair: Ca²⁺, Mg²⁺
Mg²⁺
Assign an oxidation number to each element in the following compound or ion. NH₄⁺
N is -3, H is +1
Which member of the following pair is the stronger reducing agent? Mn²⁺ or NO
NO
Choose the stronger oxidizing agent from the following pair: Hg₂²⁺, NO₃⁻
NO₃⁻
Which member of the following pair is the stronger reducing agent? Ni or I⁻
Ni
Beaker A contains a strip of nickel in aluminum sulfate, and beaker B contains a strip of aluminum in a solution of nickel sulfate. Tell what happens in each beaker and explain.
No reaction occurs in beaker A, but the aluminum strip dissolves and nickel metal forms in beaker B. Al is a stronger reducing agent than Ni, and Ni²⁺ is a stronger oxidizing agent than Al³⁺ (Ni²⁺ is below Al in Table 16.3); thus, Al is oxidized by Ni²⁺ rather than Ni getting oxididized by Al³⁺.
Are the ions that serve as charge carriers in electrochemical cells always involved in the redox reactions at the electrodes? Expalin.
No; it depends on their ease of oxidation or reduction relative to the other species present.
Explain the processes that occur at each electrode during the electrolysis of molten potassium iodide (KI).
Oxidation of I⁻ ions to form I₂ occurs at the anode (+); reduction of K⁺ ions to form molten K occurs at the cathode (-).
For voltaic cells with each of the following half-cell combinations, write the reactions occurring in each half-cell; write the overall reaction; tell which half-cell is the anode and which is the cathode; and calculate the standard cell potential. (refer to table 16.4) Cl⁻/Cl₂ and Br⁻/Br₂
Pg 286 chapter 16 review problem #6 letter a
For voltaic cells with each of the following half-cell combinations, write the reactions occurring in each half-cell; write the overall reaction; tell which half-cell is the anode and which is the cathode; and calculate the standard cell potential. (refer to table 16.4) Cr/Cr³⁺ and Cd/Cd²⁺
Pg 286 chapter 16 review problem #6 letter b
For voltaic cells with each of the following half-cell combinations, write the reactions occurring in each half-cell; write the overall reaction; tell which half-cell is the anode and which is the cathode; and calculate the standard cell potential. (refer to table 16.4) Al/Al³⁺ and Cr³⁺/Cr₂O₇²⁻
Pg 286 chapter 16 review problem #6 letter c
Where in an electrochemical cell does oxidation occur? Where does reduction occur?
Pg 286 chapter 16 review question #4
What is the standard electrode potential of a substance? How does this potential relate to the substance's position in an activity series?
Pg 286 chapter 16 review question #8
MnO₄⁻(aq) and I⁻(aq) react in basic solution to form MnO₂(s) and IO₃⁻(aq). identify the element oxidized, the element reduced, the oxidizing agent, and the reducing agent.
Pg 286 chapter review problem #2 letter a
Aluminum metal reacts with hydrochloric acid to form aluminum chloride and hydrogen gas: 2 Al(s) + 6 HCl(g)→2AlCl₃(aq) + 3 H₂ (g) Which element undergoes reduction?
hydrogen
Aluminum metal reacts with hydrochloric acid to form aluminum chloride and hydrogen gas: 2 Al(s) + 6 HCl(g)→2AlCl₃(aq) + 3 H₂ (g) Which element is the oxidizing agent? The reducing agent?
hydrogen; aluminum