Question 25.12: An aqueous solution containing aqueous gold(III) ions was el......

General Chemistry [1096620]

An aqueous solution containing aqueous gold(III) ions was electrolyzed with a current of 0.0381 amperes until 1.47 grams of gold was deposited at the cathode. Determine the duration of the experiment.

Step-by-Step

The 'Blue Check Mark' means that this solution was answered by an expert.
Learn more on how do we answer questions.

The equation for the reaction at the cathode is

Au^{3+}(aq) + 3\ e^– → Au(s)

Thus, one mole of electrons (96 485 C) deposits one-third of a mole of $Au(s)$ . The number of coulombs required to deposit 1.47 grams of $Au(s)$ is given by

Z = (1.47\ g\ Au)\left(\frac{1\ mol\ Au}{197.0\ g\ Au} \right) \left(\frac{3\ mol\ e^–}{1\ mol\ Au} \right) \left(\frac{96\ 485\ C}{1\ mol\ e^-} \right) =2160\ C

The time required at a current of 0.0381 amperes is given by (Equation 25.2)

$Z = It$ (25.2)

t =\frac{Z}{I} =\frac{2160\ C}{0.0381\ C·s^{–1}} = 5.67 × 10^{4}\ s = 15.7\ h

Related Answered Questions

Question: 25.11

A schematic diagram for a methane-oxygen fuel cell is shown in Figure 25.15. The equations for the half-cell reactions are given below. Anode: CH4(g) + 2 H2O(l) → CO2(g) + 8 H^+(aq) + 8 e^– Cathode: 2 O2(g) + 8 H^+(aq) + 8 e^– → 4 H2O(l) / Overall: CH4(g) + 2 O2(g) → CO2(g) + 2 H2O(l) Use the ...

Verified Answer:

\Delta G^{\circ}_{rxn} =\Delta G^{\circ}_{f...

Question: 25.9

Write out the cell equation for the cell Fe(s)|Fe^2+(aq, 0.100 M)||Fe^2+(aq, 2.00 M)|Fe(s) Calculate the voltage generated by this “concentration cell” at 25.0°C. Why do you think this cell is called a concentration cell? ...

Verified Answer:

The two half reactions and the corresponding value...

Question: 25.8

Use the data in Table 25.3 to determine whether Co^3+(aq), a fairly strong oxidizing agent, is capable of oxidizing water to O2(g) in acidic aqueous solution under standard conditions at 25.0°C, according to the equation 4 Co^3+(aq) + 2 H2O(l) → 4 Co^2+(aq) + O2(g) + 4 H^+(aq) ...

Verified Answer:

The oxidation of

H _{2}O(l )

to [la...

Question: 25.7

The standard voltage of the cell Zn(s)|ZnSO4(aq)||CuSO4(aq)|Cu(s) at 25.0°C is E°cell = 1.10 V. Given that E°red = –0.76 V for the electrode half reaction described by Zn^2+(aq, 1 M) + 2 e^− → Zn(s) calculate E°red at 25.0°C for the electrode half reaction given by Cu^2+(aq, 1 M) + 2 e^− → Cu(s) ...

Verified Answer:

The oxidation takes place at the left-hand electro...

Question: 25.3

Write the equations for the electrode half reactions and the net cell reaction for the electrochemical cell Cd(s)|CdSO4(aq)|Hg2SO4(s)|Hg(l) This cell does not have a salt bridge because it has only one electrolyte solution, CdSO4(aq) (all the other species are either liquids or solids). ...

Verified Answer:

By our convention, oxidation is assumed to take pl...

Question: 25.10

Another commonly used electrode that is used to measure pH is described by the cell diagram Cl^–(aq)|Hg2Cl2(s)|Hg(l) and the corresponding (reduction) half reaction Hg2Cl2(s) + 2 e^– → 2Hg(l) + 2Cl^−(aq) E°red = 0.268 V This electrode is called a calomel electrode because Hg2Cl2(s) used to be ...

Verified Answer:

The equation for the overall cell reaction is [lat...

Question: 25.6

The measured voltage at 25.0°C of a cell in which the reaction described by the equation Zn(s) + Cu^2+(aq, 1.00 M) ⇋ Cu(s) + Zn^2+(aq, 0.100 M) occurring at the concentrations given is 1.13 V. Calculate the value of E°cell for the cell. ...

Verified Answer:

Using Equation 25.13 with

ν_{e} = 2

...

Question: 25.5

The value of E°cell at 25.0°C for the equation Zn(s) + Cu^2+(aq) ⇋ Cu(s) + Zn^2+(aq) (25.11) is 1.10 V. Calculate the equilibrium constant at 25.0°C for this equation. ...

Verified Answer:

From Equation 25.10, we have

ln\ K =\frac{ν...

Question: 25.4

Consider an electrochemical cell in which the cell reaction described by the equation H2(g) + 2AgCl(s) ⇋ 2Ag(s) + 2H^+(aq) + 2Cl^−(aq) takes place. In this reaction, H2(g) reduces AgCl(s) to silver metal. Predict the effect of the following changes on the observed cell voltage: (a) increase in the ...

Verified Answer:

Using Le Châtelier’s principle, we predict the fol...

Question: 25.2

Consider the electrochemical cell shown in Figure 25.7. Indicate the current flow in the external circuit and in the cell electrolyte solutions. ...

Verified Answer:

From the figure we see that the

Pb(s)[/late...