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QUESTION 2 Mg(s) + 2Ag (aq) > 2Ag(s) + Mg* (aq) Determine which of the following statements 1s true for the chemical reaction. (A) (B) (C) (D) Silver ions are reduced and act as a reducing agent. Silver ions are oxidised and act as a reducing agent. Magnesium atoms are reduced and act as a reducing agent. Magnesium atoms are oxidised and act as a reducing agent
QUESTION 6 Calculate the cell potential produced by a Zn(s) | Zn7*(aq) || Cu**(aq) | Cu(s) galvanic cell under standard conditions. (A) -L10V (B) -0.42V (C) +0.34V (D) +110V
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 23 (6 marks) a) Identify the products of the electrolysis of 1) molten sodium chloride: [1 mark] 1) dilute aqueous sodium chloride solution: [1 mark] b) Explain how the nature of the electrolyte affects the products generated when a dilute aqueous solution of sodium chloride undergoes electrolysis. [4 marks]
QUESTION 27 (7 marks) Four unknown metals Q X Z and A were placed into separate test tubes containing a 0.1 M solution of their respective nitrate solutions. The results are shown in the table. Metal | Q(NO;) solution | X(NO3) solution | Z(NO3) solution | A(NO3) solution Coating formed Coating formed Coating formed Coating formed Coating formed Not tested coating bet Poet a) Identify the species oxidised in the reaction between Z and X(NO3)p. [1 mark] b) Identify the oxidising agent in the reaction between Z and Q(NO;) . [1 mark] c) Determine the products formed from the reaction between Z and A(NO;) . [1 mark] d) Predict the standard reduction potential table for the metals Q X Z and A by listing their reduction half-equations from strongest to weakest reducing agent. Explain your reasoning. [4 marks]
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 3 Predict which product is formed at the positive electrode when a 0.1 M aqueous solution of copper(II) sulfate is electrolysed using carbon electrodes. (A) Cu(s) (B) H (g) (C) O (g) (D) SO (g)
QUESTION 6 Which type of atoms would be more likely to gain electrons based on its position in the periodic table? (A) halogens (B) noble gases (C) alkali metals (D) alkaline earth metals
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 27 (6 marks) Arsenous acid H;AsO3 reacts with nitrate ions to form arsenic acid H;AsQOy and nitrogen dioxide. a) Determine the oxidation number of arsenic in arsenous acid. [1 mark] b) Use half-equations to balance the reaction. [4 marks] c) Determine which species is reduced in this reaction. [1 mark]
QUESTION 5 (10 marks) A sample of iron ore was tested for its iron content using the experimental procedure outlined. 8.00 g of iron Reacted with Fe2t (aq) Titrated with a | p 3+ ore sample H SO (aq) KMnO (aq) eed) All the iron (Fe) in the sample was converted to Fe** (aq) by reacting it with H SO (aq) forming hydrogen gas. The solution made up to a final volume of 500.0 mL. A 25.00 mL aliquot of the Fe** aqueous solution was titrated with a standardised solution of 0.0500 M KMnO . An average titre of 16.40 mL was obtained. a) Write a balanced chemical equation for the reaction between the iron (Fe) in the ore sample and sulfuric acid. [1 mark] b) Identify the species oxidised in the reaction in Question 5a). Explain your reasoning. [2 marks] c) Apply your understanding of half-equations to balance the redox equation. [2 marks] MnO (aq) + H (aq) + Fe (aq) > Mn? (aq) + H O()) + Fe? *(aq) d) Calculate the percentage of iron (Fe) in the ore sample. Show your working. [5 marks] Percentage iron (Fe) in ore sample = % (to one decimal place)
QUESTION 3 Which option is true for the redox equation? Fe(s) + CuCl (aq) ÔøΩ FeCl (aq) + Cu(s) (A) Fe is oxidised and Cu is the oxidising agent (B) Fe is oxidised and Cu? is the oxidising agent (C) Fe is oxidised and Cu is the oxidising agent (D) Fe** is oxidised and Cu?ÔøΩ is the oxidising agent
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 16 Determine the oxidation state of manganese in MnO . (A) (B) (C) (D) +] +2 +7 +8
QUESTION 17 Identify the redox reaction. (A) CaCO (s) > CaO(s) + CO (g) (B) CaO(s) + H 0(1) > Ca(OH) (s) (C) CL(g) + H 0() > HCl(aq) + HC1O(aq) (D) NaOH(aq) + HCl(aq) ÔøΩ NaCl(aq) + H O(1)
QUESTION 19 Three voltaic cells are constructed with metal Q as one electrode and metals R S or T as the other electrode. The potential differences for the cells are shown in the table. Voltaic cell Half-cell Half-cell Potential difference (V) Q(s)/Q**(aq) | R*(aq)/ R(s) 1.18 Q(s)/Q**(aq) | S?*(aq) / S(s) 0.72 3 T(s)/T**(aq) | Q?*(aq) / Q(s) 0.95 The relative strength of the reducing agents from strongest to weakest is (A) T>Q>S>R (B) S>Q>T>R (C) R>Q>S>T (D) Q>R>T>S
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 5 (8 marks) One step in the electrolytic refining of copper uses impure copper anodes and high purity copper cathodes in an electrolyte solution of copper(II) sulfate. a) Predict whether the concentration of the copper(II) sulfate solution will change during the purification process. Provide appropriate half-equations to support your reasoning. [4 marks] b) Ifthe copper anodes contain silver and zinc impurities determine whether either metal could be produced as a by-product of the electrolytic refining of copper. Explain your reasoning. [4 marks]
QUESTION 8 Identify the species being reduced in the equation. Br (l) + Sn**(aq) — Sn**(aq) + 2Br (aq) (A) Br (1) (B) Br (aq) (C) Sn°*(aq) (D) Sn**(aq)
QUESTION 11 The plating of silver is conducted during the operation of the electrochemical cell shown. | Voltage | _ source AgNO (aq) Determine which statement is true for this electrochemical cell. (A) The spoon acts as the cathode. (B) The silver electrode has a negative charge. (C) The silver ions in the solution are oxidised at the spoon. (D) The electrons flow from the spoon to the silver electrode.
QUESTION 24 (5 marks) R and Q are unknown transition metals from period 4 of the periodic table. Pieces of R and Q were placed separately into four 0.1 M aqueous solutions. The results are shown. 0.1 M aqueous solution Unknown oe Zn(NO3) Mg(NO3) Cu(NO3) AgNO -@[ Nocoing | Nocening | —Coving | Coming A second experiment was conducted to determine the potential difference produced by electrochemical cells constructed using metals R and Q as the electrodes. Electrochemical cell | Cathode Voltage (V) ee ee Determine the identity of metals R and Q. 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)
QUESTION 26 (5 marks) The table shows a series of reactions that were performed to produce organic compounds A B and C. conc. H SO (aq) / heat compound A and water H O(g) / heat compound B and propanol (4) KN (a) Determine the IUPAC name for compound A. [1 mark] IUPAC name: (b) Explain one structural difference between compound B and propanol. [2 marks] (c) Deduce the structural formula of compound C. [1 mark] (d) Describe one qualitative observation that would be expected for reaction 3. [1 mark]
QUESTION 25 (7 marks) During the contact process for manufacturing sulfuric acid sulfur dioxide (SO ) and oxygen (O ) are passed over a vanadium oxide catalyst to produce sulfur trioxide (SO3). In the process the vanadium oxide undergoes the following reactions. Reaction 1: SO (g) + V 0;(s) > SO3(g) + V»O (s) Reaction 2: 2V 0 (s) + O (g) — 2V 0;(s) Overall reaction: 2SO3(g) + 05(g) —225 5 280 (g) (a) Determine the oxidation state of vanadium in V 0 (s). [1 mark] (b) Determine if vanadium in V O (s) in reaction | is acting as an oxidising or reducing agent. Explain your reasoning. [2 marks] (c) Use the reactions provided to explain why V O (s) 1s a catalyst for the overall reaction. [4 marks]
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