Electrochemistry Questions and Answers

Predict the products of the double replacement reaction below. X is a group 2 element, Sr(NO3)2(aq) + XSO4(aq) → ? A. X₂NO3 + Sr₂SO4 B. X(NO3)2 + SrSO4 C. X₂NO3 + SrSO4 D. No reaction

Which metal is the least reactive one according to the fictitious reaction below? A(s) + RX(aq) → NR A. R is less reactive B. A is less reactive C. X is less reactive D. RX is less reactive

Predict the products when solutions of iron (III) chloride and X₂S are reacted. X is an alkali metal. A. Fe₂S3 and XCI B. Fe₂S and X₂CI C. FeS and X₂CI D. No reaction

When the equation PO3³-(aq) + MnO4- (aq) -------> PO4³-(aq) + MnO2 (basic solution) is balanced with the set of smallest whole number stoichiometric coefficients, the coefficients of Off and H₂0 are respectively a. 3, 3 b. 2, 2 c. 4, 2 d. 2, 1 e. none of the other answers are correct

If 12.0 g of Cr are plated from an aqueous solution containing Cr³+ ions using a current of 3.50 amps, how many minutes did the current flow? Recall the faraday is 96,500 coulombs/mole and the atomic mass of Cr= 52.00 a. 2.39 x 104 min b. 133 min c. none of the other answers are correct d. 17.3 min e. 318 min

Consider the reaction: 2HBr(g) H₂(g) + Br₂(l) Using standard thermodynamic data at 298K, calculate the entropy change for the surroundings when 2.11 moles of HBr(g) react at standard condition

Predict what happens when tin metal is placed into a solution of nickel (II) iodide. Select one: a. Tin(l) iodide forms. b. Tin metal dissolves. c. Nothing happens d. Both a and b happen. e. Nickel is plated onto tin.

select the net ionic equation for the reaction that occurs when sodium chloride and lead(II) nitrate are mixed. 2Cl(aq)-> PbCl2(S) CI (aq)-> PbCl(s) Pb2+ (aq) + Pb2+ (aq) + 2NO3(aq)-> Na2NO3(s) NO3(aq)--> NaNO3(s) 2Na (aq) + Nat (aq) +

Electrochemistry is important in many aspects of daily life. i. Define voltaic cell. ii. Fill in the blanks for the drawing of a voltaic cell that's made with copper/copper (II) nitrate (E° = 0.34 V) and zinc/zinc (II) nitrate (E° = -0.76 V). Briefly explain the role of the salt bridge. iii. Using the equation Esell- E cathode-Eanode, calculate the overall cell potential for the cell in step b. Be sure to show all steps completed to arrive at the answer.

Which of the following is TRUE of an electrolytic cell? a) It results in oxidation at the cathode. b) It involves non-spontaneous redox reactions. c) It results in reduction at the anode. d) It produces electrical energy.

Which of the following is TRUE of BOTH a galvanic and an electrolytic cell? a) They involve non-spontaneous redox reactions. b) They require the input of electrical energy to drive the reaction c) They result in oxidation at the cathode and reduction at the anode. d) None of these choices is true of both galvanic and electrolytic cells

If the molar conductance of 0.04 M solution of weak monobasic acid is 10 S cm² mol-1 and at infinite dilution is 500 S cm² mol-¹ then the dissociation constant of the acid will be 8x 10-4 1.6 x 10-5 2.4 x 10-6 X 4.0 x 10-4

When creating a tin coating for steel, calculate the mass of Sn produced when a current of 5.0 A runs through a solution of tin (IV) nitrate for 90 minutes? O a) Ob) Oc) d) 132.0 g Sn 5.89 x 10-4 g Sn 0.332 g Sn 8.30 g Sn

In a galvanic cell, ions are able to flow from one half-cell to another to prevent charge build-up via: a) a salt bridge Ob) the electrodes Oc) a voltmetre d) a battery

Correctly balance the following redox reaction equation: Cu + Ag+ Cu²++ Ag a) Cu + 2 Ag+ → Cu²+ + Ag b) Cu + 2 Ag+ c) Cu + 3 Ag+ d) 2 Cu + Ag+ → Cu²+ + 2 Ag → → Cu²+ + 3 Ag Cu²+ + Ag

To create a gold plating for copper metal, calculate the mass of Au produced when a current of 2.0 A runs through a solution of gold (III) nitrate for 60 minutes? a) Ob) O c) d) 44.1 g Au 0.082 g Au 4.90 g Au 1.22 g Au

In an electrochemical cell, which combination of half-cells would produce the highest voltage? Select one: a. Zn(s) +S₂O3(aq) Zn²+ (aq) + 2SO42- (aq) b. 2I-+S₂O82- (aq) = I₂(aq) +2 SO42- (aq) c. Ni(s) + Cl₂(g) Ni²+ (aq) + 2Cl¯ (aq) d Zn(s) + Ni2+ (aq) Ni(s) + Zn²+ (aq) e. Mg(s) + Co³+ (aq) = Mg2+ (aq) + Co²+ (aq)

In England, a miniature electric bicycle has been constructed. The Ni-Cd batteries help the rider pedal for up to 3.00 h. If a charge of 1.51 × 104 C passes through the motor during those 3.00 h, what is the current?

Given the following equation: 2 AgNO3 + CaCl2 --> 2 AgCl(s) + Ca(NO3)2 What is the net ionic equation: Ca2+ + 2 NO3 --> Ca(NO3)2 Ca²+ + 2 CI --> CaCl₂ Ag + NO3 -> AgNO3 Ag + Cl -> AgCl

Mg(s) + 2 HCl(aq) → MgCl₂(aq) + H₂(g) In an experiment, a student places a small piece of pure Mg(s) into a beaker containing 250. mL of 6.44 M HCl(aq). A reaction occurs, as represented by the equation above. (a) Write the balanced net ionic equation for the reaction between Mg (s) and HCl(aq).

When Cd²+ ions are reduced to Cd atoms at the electrode surface, the concentration of Cd²+ at the surface becomes very small. Cd2+ ions from the bulk solution then moves to the electrode surface as a result of concentration gradient. The mechanism of reactant transport to the electrode surface just described is A. convection B. migration C. diffusion D. capillary action

3Zn(OH)4²- + 2Cr 3Zn +2Cr(OH)3+ 6OH- In the above redox reaction, use oxidation numbers to identify the element oxidized, the element reduced, the oxidizing agent and the reducing agent. name of the element oxidized: formula of the oxidizing agent: name of the element reduced: formula of the reducing agent:

Order the following elements from strongest to weakest reducing agent. Refer to Appendix L. You have 3 attempts. Li, Na, K, Ca, Mg, Ba

The heat of combustion of ethanol into carbon dioxide and water is -327 kcal at constant pressure. If heat evolved (in kcal) at constant volume and 27°C (if all gases behave ideally) is x. Then find the value of x/10 (R = 2 cal mol-1 K-¹)

Complete each of the following statements below using the figure below. H3C-Br + NaOCH 3 a. In the above reaction, nucleophile. b. In the above reaction, electrophile. c. In the above reaction, group. is the c. The above reaction should proceed via an mechanism.

Which one of the reactions below is NOT a redox reaction? 2H2 +O2-> 2H2O CH4+2O2 --> CO2 + 2H20 2Al+3ZnC12->2AICI3 +3Zn AgNO3 + NaCl-> AgCl + NaNO3 C+ 2H2 --> CH4

What is oxidized in the following reaction? Cr₂O3 + 2 Al Al₂O3 + 2 Cr Consider the numbers in the formulas in the choices below to be subscripts. AI Al2O3 Cr Cr203 None of the above

Determine the equilibrium constant, K, for the voltaic cell composed of the following 2 half reactions at 298 K. Pb²+ (aq) + 2e- Pb(s) Hg2+ (aq) + 2e → Hg(s)

Determine the Eof a voltaic cell composed of Zn(s) in a 1.00 M solution of Zn²+, and Cr(s) in a 1.00 M solution of Cr³+ at 25.00°C. Zn(s)/Zn²+ Eº = -0.762 V Cr(s)/Cr³+ Eº -0.740 V

A molecular biologist measures the mass of cofactor A in an average yeast cell. The mass is 95.77 pg. What is the total mass in micrograms of cofactor A in a yeast colony containing 10 cells? Write your answer as a decimal.

Which change in the system will not affect the equilibrium in the reaction below? N2O5(g) NO2(g) + NO3(g) A) decrease the amount of NO3 B) increase the amount of N2O5 C) increase the partial pressure of NO₂(g) D) increase the total pressure E) increase the volume F) add Argon G) None of the above F G E D B A

What makes this an oxidation-reduction reaction? This is an oxidation-reduction reaction because electrons get transferred. Write the half-reactions showing the oxidation and reduction reactions. Identify which is the oxidation reaction and which is the reduction reaction. oxidation half reaction: Al→ Al+³ +3e This is an oxidation reaction because electrons are being lost. Reduction half reaction: Ag+ +eAg What is oxidized in the reaction? What is reduced? Aluminum is oxidized because its oxidation state increases, and silver is reduced because its oxidation state decreases. In this simple electrochemical cell, what functions as the anode? What is the cathode? Is this a galvanic cell or electrolytic cell? Explain your answer. What would the overall potential for this cell be?

If equivalent conductivity of K+, Al³+ and SO42- at infinite dilution is x, y and z S cm² eq-¹. The value of equivalent conductivity of Potash alum at infinite dilution is

The resistance of a conductivity cell is X2 when 0.01 M HA is present in the cell. The pH of the cell is 3, the limiting molar conductivity of HA at infinite dilution is 400 S cm² mol-1. Find the value of 'X' if the value of the cell constant is 0.01 cm -1.

If at 298 K, the solubility of AgCl in 0.05 M BaCl2(completely dissociated) is found to be very nearly 10-9 M and EAg+/Ag = -0.80V. Then the value of EºCl-/AgCl/Ag at the same temperature will be (A) 1.39 V (C) -0.7705 V (B) 0.8295 V (D) 0.21 V

Lead is listed below zinc in the activity series. What will most likely happen when zinc particles are placed in lead nitrate solution? Zinc lead will form. Oxygen will evolve. No reaction will occur. Zinc nitrate will form.

Consider these two entries from a fictional table of standard reduction potentials. X³+ + 3e¯ → X(s) E° = -2.11 V Y³+ + 3e- Y(s ) E° = -0.19 V What is the standard potential of a galvanic (voltaic) cell where X is the anode and Y is the cathode?

Consider a galvanic cell in which Al³+ is reduced to elemental aluminum and magnesium metal is oxidized to Mg2+. Write the balanced half-cell reactions that take place at the cathode and at the anode.

What essential parts are needed to make a battery? voltage regulator oxidizing agent fuse porous barrier or salt bridge reducing agent acid cell

The voltage generated by the zinc concentration cell described by the line notation Zn(s) | Zn²+ (aq, 0.100 M) || Zn²+ (aq, ? M) | Zn(s) is 17.0 mV at 25 °C. Calculate the concentration of the Zn²+ (aq) ion at the cathode.

For the galvanic (voltaic) cell Fe(s) + Mn²+ (aq) → Fe²+ (aq) + Mn(s) (E° = 0.77 V at 25°C), what is [Fe²+] if [Mn²+] = 0.065 M and E = 0.78 V? Assume T is 298 K