CHEMISTRY · Single correct · AP · Chemistry · Thermodynamics and Electrochemistry · Thermodynamics and Electrochemistry
Problem
Which of the following best explains why, for a galvanic cell in which the reaction quotient Q<1, the measured cell potential increases slightly when the temperature is raised from 298 K to 320 K?
(a) A higher temperature decreases the value of Q, shifting the reaction farther from equilibrium and therefore increasing the potential.
(b) The temperature-dependent factor RT/nF in the Nernst equation grows with T, so the −(RT/nF)lnQ term, which is positive when Q<1, contributes more strongly to the potential.
(c) The standard potential E∘ rises significantly with temperature, directly increasing the measured cell potential.
(d) Raising the temperature increases the reaction’s equilibrium constant K, pushing the cell reaction forward and thus producing a larger potential.