When a suspected drunk driver blows 188 mL of their breath through the fuel-cell breathalyzer described in Section 19.7, the breathalyzer produces an average of 324 mA of current for 10 s. Assuming a pressure of 1.0 atm and a temperature of 25 °C, what percent (by volume) of the driver’s breath is ethanol?

A rechargeable battery is constructed based on a concentration cell constructed of two Ag/Ag⁺ half-cells. The volume of each half-cell is 2.0 L, and the concentrations of Ag⁺ in the half-cells are 1.25 M and 1.0 × 10^–3 M. b. What mass of silver is plated onto the cathode by running at 3.5 A for 5.5 h?

A rechargeable battery is constructed based on a concentration cell constructed of two Ag/Ag⁺ half-cells. The volume of each half-cell is 2.0 L, and the concentrations of Ag⁺ in the half-cells are 1.25 M and 1.0 × 10^–3 M. c. Upon recharging, how long would it take to redissolve 1.00 × 10² g of silver at a charging current of 10.0 amps?

Calculate ∆G°_rxn and K for each reaction.

a. The disproportionation of Mn²⁺(aq) to Mn(s) and MnO₂(s) in acid solution at 25 °C.

b. The disproportionation of MnO₂(s) to Mn²⁺(aq) and MnO₄^–(aq) in acid solution at 25 °C.

Calculate ∆G°_rxn and K for each reaction. a. The reaction of Cr²⁺(aq) with Cr₂O₇^2–(aq) in acid solution to form Cr³⁺(aq).