Electrochemistry Quiz

Question 1Illustrative standard reduction potentials are +0.60 V at the cathode and −0.45 V at the anode. Find the standard cell potential in V, rounded to two decimals.

Enter a number in V.

Answers within 0.005 V of the expected value are accepted.

Question 2In the half-reaction Al³⁺ + n e⁻ → Al, what whole-number value of n balances charge?

Enter a number.

Answers within 0.5 of the expected value are accepted.

Question 3A steady current of 0.80 A runs for 150 s. Calculate the transferred charge in C, rounded to one decimal place.

Enter a number in C.

Answers within 0.05 C of the expected value are accepted.

Question 4A battery still contains chemicals but its voltage under load has fallen too low for a device. Which explanation fits?

The electrons have been consumed as a fuel inside the batteryThe electrolyte’s salt ions have stopped moving through the metal wireThe remaining chemicals prove that the terminal voltage stays fixedThe changing reactant conditions and internal losses reduce useful voltage

Question 5Thermodynamic data give a proposed reaction a positive standard cell potential, but it proceeds slowly. What does the positive value establish?

The electrodes deliver a large current at the proposed operating rateThe reactants finish reacting in a short fixed timeThe reaction is thermodynamically favored under standard conditionsThe reaction has a small activation barrier under standard conditions

Question 6An electrode’s atoms lose electrons during operation. Which description follows from that observation?

The electrolyte is supplying these electrons as ionsReduction occurs at this electrodeThe electrode is identified by its positive signOxidation occurs at this electrode

Question 7During an experiment, the salt bridge is removed from an otherwise connected galvanic cell. What role has been interrupted?

Electron movement directly between the two solutionsIon movement that limits charge buildup in the solutionsThe flow of electrode metal through the connecting wireA chemical source that creates fresh electrons from salt

Question 8An equation is doubled to balance its electrons with another half-reaction. What happens to its tabulated reduction potential?

It doubles because twice as many electrons are transferredIt changes sign because electrons cancel in the cell equationIt keeps the same value after the coefficients changeIt becomes zero once the electrons cancel from the equation

Question 9A more easily oxidized metal is electrically connected to a steel structure for protection. What is the intended mechanism?

The attached metal oxidizes in place of the protected steelThe attached metal replaces the electrolyte with an insulatorThe steel becomes the preferred site of metal dissolutionThe connection makes both metals resistant to losing electrons

Question 10A learner uses the negative electrode to identify the anode in both a battery and an electrolytic cell. Which rule corrects the mistake?

Identify the anode by the oxidation reactionIdentify the anode by its connection to the positive terminalIdentify the anode by where electrons are consumedIdentify the anode by the more concentrated solution

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Electrochemistry Quiz

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