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QUESTION 10 Voltage source Fork (cathode) Which of the following is true for the electrochemical cell? |Reaction |Anode =| Flow |Flowofelectrons = electrons Ss ÔøΩÔøΩÔøΩ From ÔøΩÔøΩÔøΩÔøΩÔøΩ negative terminal of the power pack through the wire to the negative electrode. spontaneous positive electrode From the positive terminal of the power pack through the wire and the electrolyte to the negative electrode. (C) | non-spontaneous | negative electrode | From the negative terminal of the power pack through the wire and the electrolyte to the positive terminal. (D) | non-spontaneous | oxidation From the negative terminal of the power pack through the wire to the negative electrode.
QUESTION 17 Which of the following represents a spontaneous redox reaction with the correct standard electrode potential? Eerie EY) (A) | 2NaÔøΩ(aq) + 2Br (aq) > 2Na(s) + Br>(aq) (B) | Sn**(aq) + 2Ag(s) > Sn(s) + 2AgÔøΩ(aq) (C) | Zn(s) + Cl (g) > Zn**(aq) + 2Cl (aq) 2.12 (D) | 2Al(s) + 3Sn**(aq) > 2A1ÔøΩ*(aq) + 3Sn(s)
QUESTION 20 This stimulus has not been published for copyright reasons. View electrochemical cell Figure 17.3 in OpenStax Galvanic Cells https://openstax.org/books/chemistry-2e/pages/17-2-galvanic-cells. Determine which of the following statements 1s true for the electrochemical cell. (A) Copper ions are reduced. (B) Copper is the positive electrode. (C) Electrons flow through the salt bridge. (D) Oxidation occurs on the surface of the copper
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Difficulty: C
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Paper 1
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2020
QUESTION 1 (12 marks) When zinc metal was placed into a blue solution of copper(II) nitrate the solution became colourless and a red-brown deposit of copper formed on the bottom of the beaker. a) Identify if the reaction that occurred can be classified as a redox reaction. Explain your reasoning. [3 marks] b) When the copper deposited in the reaction was collected and reacted with concentrated nitric acid copper(II) nitrate solution and nitrogen dioxide gas formed. Cu(s) + 4 HNO; (aq) ÔøΩ Cu(NO;) (aq) + 2 NO (g) + 2H O(1) EÔøΩ = +0.46 V 1) Determine the reduction half-equation for this reaction. [2 marks] 11) Determine the standard reduction potential EÔøΩ for the reduction half-equation. [1 mark] c) Apply your understanding of standard reduction potentials to explain why: 1) copper can dissolve in concentrated nitric acid but does not dissolve in concentrated hydrochloric acid. [3 marks] 11) NO is the gaseous product rather than H when copper dissolves in nitric acid. [3 marks]
QUESTION 24 (6 marks) The cell diagram represents a voltaic cell at standard conditions. The copper solution is blue because of the presence of Cu*(aq) ions. The acidified permanganate solution is purple because of the presence of MnO (aq) ions. Half-cell Half-cell ÔøΩÔøΩÔøΩ_ ÔøΩÔøΩ____ Cu(s) | Cu** (aq) | | MnO (aq) | Pt(s) Salt bridge a) Predict which direction the electrons will flow in the voltaic cell by comparing the relative strength of the oxidising agents. Explain your reasoning. [3 marks] b) Determine the standard reduction potential EÔøΩ for the cell. [1 mark] c) Predict two qualitative observations associated with the flow of electrons and the movement of ions in the voltaic cell. [2 marks]
QUESTION Il Determine the species that travels through the salt bridge towards the reduction half-cell in the electrochemical cell at standard conditions. Salt bridge (A) zinc ions (B) nitrate ions (C) copper ions (D) potassium ions
QUESTION 12 The zinc electrode Cu electrode (v) KNO Salt bridge Cp \ Cu*(aq) NO; (aq) (A) gains electrons and acts as the anode. (B) acts as the cathode and has a positive charge. (C) undergoes reduction and has a negative charge. (D) is oxidised and donates electrons to the copper ions. ET / \ ÔøΩ \ 7 S 7 2 - u- ZnÔøΩ*(aq) Zn electrode NO; (aq)
QUESTION 24 (7 marks) This electrochemical cell was constructed using copper and platinum electrodes. Cu(s) | CuÔøΩ*(aq) (1M) || Fe**(aq) (1M) Fe**(aq) (1M) | Pt(s) a) Compare the standard electrode potential (ÔøΩÔøΩ) of the two half-cells. Similarity: Difference: Significance: b) Write a balanced redox equation for the electrochemical cell. c) Determine the cell potential (in volts) for the electrochemical cell. Cell potential = V (to two significant figures) d) Determine the oxidising agent. Explain your reasoning
QUESTION 3 (7 marks) An experiment was conducted at standard state conditions to investigate the potential difference (V) produced by different galvanic cells. The three cells used in the experiment are shown. graphite Cell 1 graphite Cell 2 graphite Cell 3 (a) Predict which cell produced the highest voltage. Explain your reasoning. [3 marks] (b) Determine the maximum voltage that could be produced by a fourth galvanic cell constructed from any of the components used in the first three cells. Use oxidation and reduction half-equations to justify your answer. [4 marks]
QUESTION 7 Determine which half-cell produces the largest potential difference when joined with a Zn(s) | Zn7*(aq) half-cell to form a galvanic cell. (A) Mg(s) | Mg**(aq) (B) Cu’*(aq) | Cu(s) (C) H*(aq) | H (g) (D) F (g)|F (aq)
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