Zadanie 1e
Many rechargeable batteries use an alkaline electrolyte. In the nickel-cadmium cell, cadmium, Cd, is the anode. Cd(OH)2(s) + 2 e− → Cd(s) + 2 OH−(aq) E⊖ = −0.81 V…
Standard cell potential and spontaneity
Calculate E°cell = E°(cathode) - E°(anode) from standard electrode potentials, identify which half-cell is oxidized, and predict whether a redox reaction is spontaneous in the forward or reverse direction from the sign of E°cell.
Tę umiejętność sprawdzają 24 zadania wzorowane na arkuszach IB z lat 2022–2026.
Zadania sprawdzające tę umiejętność: 24 Otwórz w wyszukiwarce z filtrami
Zadanie 40
An electrochemical cell is written in cell notation with its standard cell potential. Pb(s) ∣ Pb2+(aq) ∣∣ Mg2+(aq) ∣ Mg(s) Ecell⊖ = −2.24 V What is correct about the cell reaction as written? In each option the sign of…
Zadanie 37
What is the standard cell potential, Ecell⊖, of the following cell? Pb2+(aq) + 2 e− ⇌ Pb(s) E⊖ = −0.13 V Zn2+(aq) + 2 e− ⇌ Zn(s) E⊖ = −0.76 V A. −0.89 V B. −0.63 V…
- Materiał graficzny
Zadanie 39
The table shows standard electrode potentials for three metals. Which combination undergoes a spontaneous reaction under standard conditions? A. Cd and Cr3+ B. Cr and Cd2+ C. Cr and Mn2+ D. Cd and Mn2+
- Tabela do uzupełnienia
Zadanie 2c
Using section 19 of the data booklet, predict and explain what would be observed if zinc and silver metals were each added to a separate sample of blue copper(II) sulfate solution.
- Tabela do uzupełnienia
Zadanie 4b
The electrode potential, E, of the Sn4+/Sn2+ half-cell is not fixed: it depends on the concentrations of the two tin ions, as given by the equation: Determine the electrode…
Zadanie 5a
(i) In the nickel–metal hydride (NiMH) rechargeable battery the negative electrode is a metal alloy, M, that absorbs hydrogen. The two electrode reactions during discharge are shown below.…
- Materiał graficzny
Zadanie 5b
For a different pair of half-cells, the standard Gibbs energy change, ΔG⊖, works out to −370.6 kJ mol−1, with a single electron transferred between the electrodes in the cell reaction. Deduce what these two half-cells are. Use…
Zadanie 35
A voltaic cell is made by connecting a manganese half-cell (Mn(s) in Mn2+(aq)) and a tin half-cell (Sn(s) in Sn2+(aq)) under standard conditions. Mn2+(aq) + 2 e− ⇌ Mn(s) E⊖ = −1.18 V…
Zadanie 7b
A standard hydrogen electrode is connected to a half-cell consisting of a zinc rod in a solution of zinc nitrate, Zn(NO3)2(aq), to form a voltaic cell. (i) Write the cell diagram for the spontaneous reaction, using "|" for a phase boundary and "||" for…
Zadanie 7e
The diagram shows a voltaic cell made from a zinc half-cell and a copper half-cell. The salt bridge contains aqueous potassium nitrate, KNO3(aq). Electrons flow through the external circuit in the direction shown. Use section 19 of the data booklet to…
- Materiał graficzny
Zadanie 8a
The diagram shows the apparatus. The left-hand half-cell is the anode and the right-hand half-cell is the cathode; the electrodes and solutions are not labelled. State which electrode and which solution are in each half-cell, and state the direction of…
- Materiał graficzny
Zadanie 29
A voltaic cell is constructed from a half-cell of metal M in a solution of M2+ ions and a half-cell of metal N in a solution of N2+ ions. The half-cells are joined by a salt bridge and an external wire.…
Zadanie 31
A half-cell of metal X in a 1.00 mol dm−3 solution of X2+ ions is connected to a standard hydrogen electrode (SHE). The voltmeter reads 0.34 V and the X electrode is the positive terminal. Which statement is correct? A. The standard…
Zadanie 4b
(i) Outline why electrons flow from the iron half-cell to the copper half-cell when the two are connected by a wire. Use section 19 of the data booklet. (ii) Formulate equations for the reactions taking place at the anode (negative electrode) and at the…
Zadanie 4c
(i) Calculate the standard cell potential for the voltaic cell. Use section 19 of the data booklet. (ii) Calculate the standard Gibbs energy change, ΔG⊖, in kJ mol−1, for the cell reaction. Use sections 1 and 2 of the data…
Zadanie 30
The standard electrode potentials of two half-cells are given below. The cell is represented as Which expression gives the standard cell potential, in V? A. 0.34 + 3(1.66) B. 0.34 + 1.66 C.…
- Tabela do uzupełnienia
Zadanie 5f
The standard electrode potential, E⊖, of the half-cell Al3+(aq) + 3 e− ⇌ Al(s) is −1.66 V. (i) Calculate the standard cell potential for the reaction 2 Al(s) + 6 H2O(l) → 2 Al3+(aq) + 6 OH−(aq) + 3 H2(g) Use section 19 of the data…
Zadanie 5f
(i) Calculate the standard cell potential for the reaction 2 Al(s) + 6 H2O(l) → 2 Al3+(aq) + 6 OH−(aq) + 3 H2(g) Use section 19 of the data booklet. (ii) Deduce whether this reaction is spontaneous under standard conditions at 298 K, and give a reason.
Zadanie 2b
A block of zinc attached to a steel structure acts as a sacrificial anode. (i) Calculate the standard cell potential, in V, of a cell made from zinc and steel half-cells. Use section 19 of the data booklet and take the standard electrode potential of steel to…
Zadanie 3a
(i) Silver ions oxidize copper metal. 2 Ag+(aq) + Cu(s) → 2 Ag(s) + Cu2+(aq) Calculate the standard cell potential, Ecell⊖, in V, for this reaction. Use section 19 of the data booklet. (ii) Determine, giving a reason, whether lead(II)…
Zadanie 30
Which E⊖ value, in V, for the reaction Mg(s) + Fe2+(aq) → Mg2+(aq) + Fe(s) can be deduced from the following equations? Mg(s) + 2 Ag+(aq) → Mg2+(aq) + 2 Ag(s) E⊖ = 3.17 V…
Zadanie 3f
The diagram shows an unlabelled voltaic cell for the reaction: Ni(s) + 2 Ag+(aq) → Ni2+(aq) + 2 Ag(s) (i) Identify, using species from the equation, what W, X, Y and Z are, and state the direction of electron flow in the external circuit. (ii) Write the…
- Materiał graficzny
Zadanie 30
Some standard electrode potentials for copper are shown. Cu2+(aq) + e− ⇌ Cu+(aq), E⊖ = +0.15 V Cu+(aq) + e− ⇌ Cu(s), E⊖ = +0.52 V Cu2+(aq) + 2 e− ⇌ Cu(s), E⊖ = +0.34 V…