Reactivity 3: electron transfer (HL)

15 original questions · 15 derived marking activities. Teaching explanations are AI-authored; independent teacher review is pending.

15 of 30 activities match

• Question 1Define oxidation and reduction in terms of electron transfer.AI checkedFoundation2 marksNo calculator+
• Question 3Using standard electrode potentials E°(Cu²⁺/Cu) = +0.34 V and E°(Zn²⁺/Zn) = −0.76 V, calculate E°cell for the reaction Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s), stating which half-cell is the cathode.AI checkedStandard4 marksCalculator+
• Question 5State how the sign of E°cell indicates whether a redox reaction is spontaneous under standard conditions, and hence state whether the reaction between Zn(s) and Cu²⁺(aq) is spontaneous, given E°cell = +1.10 V.AI checkedStandard2 marksNo calculator+
• Question 7A current of 2.00 A is passed through molten lead(II) bromide, PbBr₂(l), for 1930 seconds using inert electrodes. Calculate the number of moles of electrons transferred. (F = 96500 C mol⁻¹)AI checkedEnrichmentStandard4 marksCalculator+
• Question 9Using n(e⁻) = 0.0400 mol from the electrolysis of molten PbBr₂, calculate the mass of lead deposited at the cathode. (Pb²⁺ + 2e⁻ → Pb; Ar(Pb) = 207)AI checkedStandard3 marksCalculator+
• Question 11Explain why the standard hydrogen electrode (SHE) is assigned a standard electrode potential of exactly 0.00 V, and outline why this matters for tabulating other electrode potentials.AI checkedStandard3 marksNo calculator+
• Question 13Aqueous copper(II) sulfate is electrolysed using inert platinum electrodes under the usual laboratory conditions. Identify the cathode and anode products, explain why water rather than sulfate is oxidised at the anode, and write a balanced anode half-equation.AI checkedChallenge4 marksNo calculator+
• Question 15Two electrolytic cells are connected in series: one contains molten PbBr2 and the other aluminium oxide dissolved in molten cryolite. Assume 100% current efficiency for metal deposition in each. Deduce which cell deposits more moles of metal for the same charge and explain why. Use Pb2+ + 2e- -> Pb and Al3+ + 3e- -> Al.AI checkedStandard3 marksNo calculator+
• Question 17State the Nernst equation. For Zn(s) + Cu2+(aq) -> Zn2+(aq) + Cu(s) at fixed temperature, explain how increasing only [Cu2+] above 1 mol dm^-3 affects cell potential when [Zn2+] remains at 1 mol dm^-3. Treat ion activities as proportional to concentration.AI checkedEnrichmentChallenge3 marksNo calculator+
• Question 19A current of 1.5 A is passed through molten aluminium oxide to deposit aluminium metal at the cathode: Al³⁺ + 3e⁻ → Al. Calculate the time required to deposit 2.70 g of aluminium. (Ar(Al) = 27, F = 96500 C mol⁻¹)AI checkedEnrichmentChallenge5 marksCalculator+
• Question 21State one practical reason for electroplating an object with a metal such as chromium or silver, and outline the role of the object being plated in the electrolytic cell.AI checkedFoundation3 marksNo calculator+
• Question 23Outline how a hydrogen-oxygen fuel cell generates electrical energy, including the half-equations at each electrode in alkaline conditions, and state one advantage of a fuel cell compared with burning hydrogen directly as a fuel.AI checkedChallenge4 marksNo calculator+
• Question 25Distinguish between a primary cell and a secondary cell, giving one example of each.AI checkedFoundation2 marksNo calculator+
• Question 27Write the standard cell notation (cell diagram) for a voltaic cell made from a Zn(s)/Zn²⁺(aq) half-cell and a Cu(s)/Cu²⁺(aq) half-cell, given that zinc is the more easily oxidised metal.AI checkedEnrichmentStandard3 marksNo calculator+
• Question 29Explain, in terms of electron transfer, why iron rusts when exposed to both oxygen and water, and state one method of preventing rusting based on this mechanism.AI checkedChallenge4 marksNo calculator+