Exam 20: Principles of Chemical Reactivity: Electron Transfer Reactions

Calculate E_cell for the following electrochemical cell at 25 °C. Pt(s) | Fe³⁺(aq, 0.100 M), Fe²⁺(aq, 0.040 M) || Cl^-(aq, 0.50 M) | AgCl(s) | Ag(s) The standard reduction potentials are as follows: AgCl(s) + e^- → Ag(s) + Cl^-(aq) E° = +0.222 V Fe³⁺(aq) + e^- → Fe²⁺(aq) E° = +0.771 V

Which of the following statements is true for electron transfer reactions?

Write a balanced net ionic equation for the reaction below in an acidic solution. Cr₂O₇^2-(aq) + Ni(s) ? Cr³⁺(aq) + Ni²⁺(aq)

Write a balanced chemical equation for the following reaction in a basic solution. ClO^-(aq) + Cr(OH)₃(s) ? Cl^-(aq) + CrO₄^2-(aq)

Write the balanced oxidation half-reaction for the following overall reaction: 2 H⁺(aq) + Ca(s) → Ca²⁺(aq) + H₂(g)

Calculate the value of the reaction quotient, Q, for the voltaic cell constructed from the following two half-reactions when the Zn²⁺ion concentration is 0.0110 M and the Ag⁺ ion concentration is 1.27 M? $\mathrm { Zn } ^ { 2 + } ( \mathrm { aq } ) + 2 \mathrm { e } ^ { - }$ ? $\mathrm { Zn } ( \mathrm { s } ) ; E ^ { \circ } = - 0.76 \mathrm {~V}$ $\mathrm { Ag } ^ { + } ( \mathrm { aq } ) + \mathrm { e } ^ { - }$ ? $\mathrm { Ag } ( \mathrm { s } ) ; E ^ { \circ } = 0.80 \mathrm {~V}$

Which of the following statements is true for the following reaction, assuming the given reaction proceeds in the forward direction? 3 Sn⁴⁺(aq) + 2 Cr(s) → 3 Sn²⁺(aq) + 2 Cr³⁺(aq)

Write a balanced chemical equation for the oxidation of solid cadmium by concentrated nitric acid, producing nitrogen dioxide gas and Cd²⁺(aq) ion.

Write the balanced reduction half-reaction for the following overall reaction: 2 Fe(s) + 3 Cl2(aq) → 2 Fe3+(aq) + 6 Cl-(aq)

Use the following standard reduction potentials to determine which species is the strongest oxidizing agent. Fe²⁺(aq) + 2 e^- ? Fe(s); E° = -0.41 V Pt²⁺(aq) + 2 e^- ? Pt(s); E° = 1.18 V Cr₂O₇^2-(aq) + 14 H⁺(aq) + 6 e^- ? 2 Cr³⁺(aq) + 7 H₂O( $\ell$ ); E° = 1.33 V

Aluminum(III) ion (Al³⁺) is reduced to solid aluminum at an electrode. If a current of 2.75 amperes is passed for 36 hours, calculate the mass of aluminum deposited at the electrode. (Assume 100% current efficiency.)

Calculate the equilibrium constant for the reaction below at 25 °C. Co(s) + 2 Cr³⁺(aq) → Co²⁺(aq) + 2 Cr²⁺(aq) The standard reduction potentials are as follows: Co²⁺(aq) + 2 e^- → Co(s) E° = -0.28 V Cr³⁺(aq) + e^- → Cr²⁺(aq) E° = -0.41 V

Calculate the copper(II) ion concentration at 25 °C in the cell Zn(s) | Zn²⁺(aq, 1.0 M) || Cu²⁺(aq) | Cu(s) if the measured cell potential is 1.06 V. The standard cell potential is 1.10 V.

If the $E _ { \text {cell } } ^ { \circ }$ = -0.362 V for a given electrochemical cell at 25 °C, calculate the pH of the solution at the cathode. Pt | H₂(g, 1.0 atm) | H⁺(aq, 1.00 M) || H⁺(aq) | H₂(g, 1.0 atm) | Pt

Use the following standard reduction potentials to determine which species is the best oxidizing agent. ()+4()+4\rightarrow2(\ell) =+1.229 ()+2\rightarrow2(\ell) =+0.789 ()+2\rightarrow2() =+0.535

Claculate the mass of chromium that can be deposited by electrolysis of an aqueous solution of chromium(III) sulfate, Cr₂(SO₄)₃, for 180 min using a constant current of 11.0 A. Assume 100% current efficiency. (F = 96485 C/mol)

When the given oxidation-reduction reaction in an acidic solution is balanced, what is the lowest whole-number coefficient for H⁺, and on which side of the balanced equation should it appear? MnO₄^-(aq) + Br^-(aq) → Mn²⁺(aq) + Br₂(l)

Calculate the charge, in coulombs, is required to deposit 1.5 g of solid magnesium from a solution of Mg²⁺(aq) ion.

Consider the following half-reactions. Ag⁺(aq) + e^- → Ag(s) E° = +0.80 V Cu²⁺(aq) + 2 e^- → Cu(s) E° = +0.34 V Pb²⁺(aq) + 2 e^- → Pb(s) E° = -0.13 V Fe²⁺(aq) + 2 e^- → Fe(s) E° = -0.44 V Al³⁺(aq) + 3 e^- → Al(s) E° = -1.66 V Which of the following species will oxidize lead, Pb(s)?

When a secondary battery provides electrical energy, it is acting as a voltaic cell. When the battery is recharging, it is operating as a(n) _____ cell.