A voltaic cell is constructed in which the anode is a Cr²+ | Cr³+ half cell and the cathode is a Fe²+ | Fe³+ half cell. The half-cell compartments are connected by a salt bridge. (Use the lowest possible coefficients. Be sure to specify states such as (aq) or (s). If a box is not needed, leave it blank.) The anode reaction is: + The cathode reaction is: + The net cell reaction is: + In the external circuit, electrons migrate | electrode. In the salt bridge, anions migrate compartment. + the Fe²+ | Fe³+ electrode ( the Cr²+ | Cr³+ compartment ( the Cr²+ | Cr³+ *|Fe3+ the Fe²+

A voltaic cell is constructed in which the following cell reaction occurs. The half-cell compartments are connected by a salt bridge. Ni²+ (aq) + Mn(s) →→→ Ni(s) + Mn²+(aq) The anode reaction is: + The cathode reaction is: In the external circuit, electrons migrate In the salt bridge, anions migrate compartment. + the Ni Ni2+ electrode the Ni Ni2+ compartment ( Ac the Mn| Mn²+ electrode.. the Mn|Mn²+

A fast, reversible, single electron, charge transfer reaction is being investigated with CV. For a scan rate of 50 mV/s, a bulk concentration of 3.2 mmol/L, B = 0.5 and a diffusion coefficient of 10^-5 cm2/s what was the maximum peak current density? A) 7.4 A/cm2 B) 5.2 mA/cm2 C) 5.2 A/cm2 D) 7.4 mA/cm2 Points Earned: Correct Answer(s): D 0.0/4.0

Calculate the diffusion overpotential for hydrogen formation, 2H+(aq) + 2e- = H2(g) at current density of 0.25 A/cm2 and temperature of 25 °C, if the limiting current is 1 A/cm2 A) -7.40 mV B) -0.31 mV C) -3.70 mV Points Earned: Correct Answer(s): C 4.0/4.0

When the following half reaction is balanced under acidic conditions, what are the coefficients of the species shown? | Cl₂ + H₂O CIO3+ H+ In the above half reaction, the oxidation state of chlorine changes from + to +

A voltaic cell is constructed from a standard Sn²+ | Sn half cell (E° red = -0.140V) and a standard Cd²+ | Cd 2+ half cell (Eºred = -0.403V). The anode reaction is: + The cathode reaction is: + The spontaneous cell reaction is: + The cell voltage is V. 1 + + +

For a Cu2+/Cu+ electrochemical couple under charge transfer control with an exchange current density of 2 10^-3 A/cm2, an asymmetry parameter of 0.5 and an overpotential of 5 mV at 25 °C, what is the theoretical current density? A) 1.40 mA/cm2 B) 701 mA/cm2 C) 0.70 mA/cm2 D) 8.36 mA/cm2 Points Earned: Correct Answer(s): C 0.0/4.0

A voltaic cell is constructed from a standard Co²+ | Co half cell (E° red = -0.280V) and a standard Cu²+ | Cu* half cell (E° red= 0.153V). (Use the lowest possible coefficients. Be sure to specify states such as (aq) or (s). If a box is not needed, leave it blank.) The anode reaction is: + The cathode reaction is: + The spontaneous cell reaction is: + The cell voltage is V. + + + A

Calculate the anodic charge transfer overpotential for the oxygen half-reaction, (1/2)02(g) + 2H+ + 2e = H2O(l) on Pt in 1 mol/L H2SO4(aq) solution at 25 °C if the exchange current density is 10-6 A/cm2, the transfer coefficient is 0.75, the current density is 0.1 A/cm2 and the limiting current density is 0.2 A/cm2 A) 8.90 mV B) 0.383 V C) 0.592 V Points Earned: Correct Answer(s): C 0.0/4.0

for a Cu2+/Cu+ electrochemical couple with a diffusion coefficient for the electrochemically active species as 10^-5 cm2/s, a bulk concentration of 2 mol/L, a Nernst diffusion layer of 10 μm and a current density of 0.5 A/cm2 at 25 °C, what is the theoretical mass transfer overpotential? A) -0.67 mV B) -6.66 mV C) -7.71 mV D) 14.21 mV Points Earned: Correct Answer(s): C 0.0/4.0