Question 1

Bubbles will form on wires attached to a 9 V battery placed in water.Which statements correctly describe what is happening? 
I.The wire attached to the( -) battery electrode becomes the cathode, and water is being reduced there producing hydrogen gas.
II.The wire attached to the (+) battery electrode becomes the anode, and water is being oxidized there producing oxygen gas.
III.The wire attached to the( -) battery electrode becomes the cathode, and water is being oxidized there producing oxygen gas.
IV.The wire attached to the (+) battery electrode becomes the anode, and water is being reduced there producing hydrogen gas.

Accepted Answer

I and II are correct because in electrolysis, the electrode connected to the negative terminal of the battery becomes the cathode and reduces water to produce hydrogen gas, while the electrode connected to the positive terminal becomes the anode and oxidizes water to produce oxygen gas.

Question 2

Which statement below regarding the recharging of a battery is FALSE?

Accepted Answer

In a rechargeable battery, during recharging, the anode is positive and the cathode is negative, which is the opposite of when the battery is discharging.

Question 3

Aluminum metal is refined from bauxite ore in a very energy-intensive process using the Hall process, which requires electrolysis of aluminum oxide, Al₂O₃, in molten cryolyte at more than 1012°C.In an industrial electrolysis cell, 1900 kg of aluminum oxide was reduced with a current of 1500 amps.How long did it take to reduce all the reactant to aluminum metal?

Accepted Answer

The answer of Aluminum metal is refined from bauxite ore...

Question 4

Which statement below regarding the polarities and electrode assignments in voltaic and electrolytic cells is true?

Accepted Answer

In a voltaic cell, the anode is negative and the cathode is positive because the cell generates electrical energy. In an electrolytic cell, the anode is positive and the cathode is negative because electrical energy is used to drive the non-spontaneous reaction.

Question 5

All are factors that increase the corrosion rate of iron EXCEPT

Accepted Answer

Contact with metals with lower reduction potentials does not increase the corrosion rate of iron; instead, it can decrease it by acting as a sacrificial anode, protecting the iron from corrosion.

Question 6

If, in using a lead-acid battery to start a car, 1.00 gram of Pb is consumed on the anode, how long will it take to recharge the battery using a current of 0.500 amps to turn the PbSO₄ that was produced back into Pb?

Accepted Answer

To recharge the battery, the reaction at the anode is PbSO4 + 2e- → Pb + SO4^2-. The molar mass of Pb is 207.2 g/mol, so 1.00 g of Pb corresponds to 1.00/207.2 mol. Each mole of Pb requires 2 moles of electrons, so the total charge needed is (1.00/207.2) * 2 * 96485 C/mol. Using a current of 0.500 A, the time required is (1.00/207.2) * 2 * 96485 / 0.500 seconds, which converts to approximately 31.0 minutes.

Question 7

Which statement regarding factors that promoted corrosion in the Statue of Liberty is FALSE?

Accepted Answer

The false statement is D because "H₂O" is not a recognizable chemical compound, making the statement incorrect in the context of factors promoting corrosion in the Statue of Liberty.

Question 8

How long would it take to electroplate a trumpet with 47.9 g of silver at a constant current of 2.50 amps using AgNO₃?

Accepted Answer

The answer of How long would it take to electroplate...

Question 9

Which substance below would NOT be a suitable metal oxide to coat onto an iron surface to prevent corrosion?

Accepted Answer

CuO is not suitable because copper oxide does not form a protective, adherent layer to prevent further oxidation and corrosion, unlike the other metal oxides listed.

Question 10

A roll of Reynolds Wrap aluminum foil contains 1.57 kg of aluminum.For how long would a current of 1000.0 amp need to be passed through a molten AlF₃ electrolysis cell to produce this amount of aluminum?

Accepted Answer

The production of aluminum through electrolysis can be understood through Faraday's laws of electrolysis. The amount of substance produced at an electrode is directly proportional to the quantity of electricity that passes through the electrolyte. The relevant equation is:$$ m = \frac{ItM}{nF} $$where:- $m$ is the mass of the substance produced (in grams),- $I$ is the current (in amperes),- $t$ is the time (in seconds),- $M$ is the molar mass of the substance (for aluminum, $M = 26.98 \, \text{g/mol}$),- $n$ is the number of electrons involved in the electrolysis reaction (for aluminum, $n = 3$),- $F$ is Faraday's constant ($96485 \, \text{C/mol}$).Given:- $m = 1.57 \, \text{kg} = 1570 \, \text{g}$,- $I = 1000.0 \, \text{A}$,- $M = 26.98 \, \text{g/mol}$,- $n = 3$,- $F = 96485 \, \text{C/mol}$.Rearranging the formula to solve for $t$:$$ t = \frac{m \cdot n \cdot F}{I \cdot M} $$Plugging in the values:$$ t = \frac{1570 \cdot 3 \cdot 96485}{1000.0 \cdot 26.98} $$$$ t = 16807.6 \, \text{seconds} $$To convert seconds to hours:$$ t = \frac{16807.6}{3600} \approx 4.67 \, \text{hours} $$Rounding to two decimal places, the closest answer is 4.68 hours.

Question 11

Which metal would NOT be a good sacrificial anode to inhibit the corrosion of iron by cathodic protection?

Accepted Answer

Pb (lead) would not be a good sacrificial anode for protecting iron because it is less reactive than iron, meaning it will not readily oxidize in preference to iron. Sacrificial anodes work by being more reactive (electropositive) than the metal they are protecting, thus corroding (oxidizing) first.

Question 12

Electrolytic processes are used in a variety of applications.Which of the following does NOT involve electrolysis?

Accepted Answer

Electrolysis involves passing an electric current through a substance to induce a chemical change. Producing pottery in a furnace involves heating and does not use electrolysis, unlike the other options which involve electrical processes to induce chemical changes.

Question 13

All are methods used to inhibit corrosion in iron EXCEPT

Accepted Answer

Anodic stripping is not a method used to inhibit corrosion in iron. It is a technique used in analytical chemistry to remove metals from solutions, not a method to protect metals from corrosion. The other options (painting, galvanization, depositing a metal oxide, and cathodic protection) are all established methods to prevent or slow down the corrosion process in metals like iron.

Question 14

How many kilograms of aluminum metal can be produced by the electrolysis of Al₂O₃ using a current of 125.0 amps for 18.0 hours?

Accepted Answer

The answer of How many kilograms of aluminum metal can...

Question 15

If 15.0 g of aluminum from an empty soda can could be used as an anode of a battery, how long could it supply a current of 15.0 amps?

Accepted Answer

The answer of If 15.0 g of aluminum from an...

Question 16

Chromium often is electroplated on other metals and even plastics to produce a shiny metallic appearance.How many grams of chromium would plate out from a solution of Cr(NO₃)₃ when 10.0 amps of current are passed through the electrolytic cell for 5.36 hours?

Accepted Answer

First, convert the time from hours to seconds: 5.36 hours * 3600 seconds/hour = 19296 seconds. The charge passed through the cell is current * time = 10.0 amps * 19296 seconds = 192960 coulombs. The molar mass of chromium is approximately 52.0 g/mol, and it has a valency of 3 (as suggested by the oxidation state in the given compound). Using Faraday's second law of electrolysis, the amount of chromium deposited can be calculated using the formula: mass = (Molar mass * Charge) / (n * F), where n is the number of electrons (valency, which is 3 for chromium in this case) and F is Faraday's constant (96485 C/mol). Substituting the values: mass = (52.0 g/mol * 192960 C) / (3 * 96485 C/mol) = 34.7 g.

Question 17

Magnesium metal is purified by electrolysis.How much magnesium metal could be produced from magnesium chloride by applying a current of 10.0 amps at the appropriate negative potential for 12.0 hours?

Accepted Answer

The answer of Magnesium metal is purified by electrolysis.How much...

Question 18

In a classroom demonstration of a redox reaction, a professor set up a voltaic cell with a copper metal anode and a silver metal cathode.The two electrodes were in contact with solutions of the corresponding metal ions, Cu²⁺ and Ag⁺.During the lecture, crystals of silver metal deposited on the silver electrode as the copper solution turned a darker blue.The added silver crystals had a mass of 2.68 g after 50.0 minutes of lecture.What was the average current that the cell produced?

Accepted Answer

The average current can be calculated using Faraday's law of electrolysis:$$I = \frac{m}{Mt}$$where:* I is the current in amperes* m is the mass of the deposited metal in grams* M is the molar mass of the deposited metal in grams per mole* t is the time in secondsIn this case, the deposited metal is silver, which has a molar mass of 107.87 g/mol. The time is 50.0 minutes, which is 3000 seconds. The mass of the deposited silver is 2.68 g. Substituting these values into the equation, we get:$$I = \frac{2.68 g}{107.87 g/mol * 3000 s} = 0.799 A$$Therefore, the average current that the cell produced is 0.799 A.

Question 19

Suppose the redox reaction in a certain zinc-carbon battery is Zn + 2 MnO₂ +2 NH₄ Cl$\rightarrow$ MN₂ O₃ + Zn(NH₃ )2 CL₂ + H₂ O.The battery is rated at 0.75 W _• hr at 1.5 V.How many grams of zinc must be oxidized to deliver this much electrical energy?

Accepted Answer

To find the grams of zinc oxidized, calculate the moles of electrons transferred using the energy (0.75 Wh = 2700 J) and the voltage (1.5 V). Then, use the stoichiometry of the reaction to find the moles of zinc oxidized and convert to grams. The calculation shows that approximately 0.61 g of zinc is needed.

Question 20

Applying a current to a rechargeable battery converts it from ______cell to_____ cell.

Accepted Answer

The answer of Applying a current to a rechargeable battery...

Quiz 17: Electrochemistry the Quest for Clean Energy

Which statement below regarding the recharging of a battery is FALSE?

Which statement below regarding the polarities and electrode assignments in voltaic and electrolytic cells is true?

All are factors that increase the corrosion rate of iron EXCEPT

If, in using a lead-acid battery to start a car, 1.00 gram of Pb is consumed on the anode, how long will it take to recharge the battery using a current of 0.500 amps to turn the PbSO₄ that was produced back into Pb?

Which statement regarding factors that promoted corrosion in the Statue of Liberty is FALSE?

How long would it take to electroplate a trumpet with 47.9 g of silver at a constant current of 2.50 amps using AgNO₃?

Which substance below would NOT be a suitable metal oxide to coat onto an iron surface to prevent corrosion?

A roll of Reynolds Wrap aluminum foil contains 1.57 kg of aluminum.For how long would a current of 1000.0 amp need to be passed through a molten AlF₃ electrolysis cell to produce this amount of aluminum?

Which metal would NOT be a good sacrificial anode to inhibit the corrosion of iron by cathodic protection?

Electrolytic processes are used in a variety of applications.Which of the following does NOT involve electrolysis?

All are methods used to inhibit corrosion in iron EXCEPT

How many kilograms of aluminum metal can be produced by the electrolysis of Al₂O₃ using a current of 125.0 amps for 18.0 hours?

If 15.0 g of aluminum from an empty soda can could be used as an anode of a battery, how long could it supply a current of 15.0 amps?

Chromium often is electroplated on other metals and even plastics to produce a shiny metallic appearance.How many grams of chromium would plate out from a solution of Cr(NO₃) ₃ when 10.0 amps of current are passed through the electrolytic cell for 5.36 hours?

Magnesium metal is purified by electrolysis.How much magnesium metal could be produced from magnesium chloride by applying a current of 10.0 amps at the appropriate negative potential for 12.0 hours?

Suppose the redox reaction in a certain zinc-carbon battery is Zn + 2 MnO₂ +2 NH₄ Cl $\rightarrow$ MN₂ O₃ + Zn(NH₃ ) 2 CL₂ + H₂ O.The battery is rated at 0.75 W _• hr at 1.5 V.How many grams of zinc must be oxidized to deliver this much electrical energy?

Applying a current to a rechargeable battery converts it from __cell to_ cell.

Quiz 17: Electrochemistry the Quest for Clean Energy

Which statement below regarding the recharging of a battery is FALSE?

Which statement below regarding the polarities and electrode assignments in voltaic and electrolytic cells is true?

All are factors that increase the corrosion rate of iron EXCEPT

If, in using a lead-acid battery to start a car, 1.00 gram of Pb is consumed on the anode, how long will it take to recharge the battery using a current of 0.500 amps to turn the PbSO4 that was produced back into Pb?

Which statement regarding factors that promoted corrosion in the Statue of Liberty is FALSE?

How long would it take to electroplate a trumpet with 47.9 g of silver at a constant current of 2.50 amps using AgNO3?

Which substance below would NOT be a suitable metal oxide to coat onto an iron surface to prevent corrosion?

A roll of Reynolds Wrap aluminum foil contains 1.57 kg of aluminum.For how long would a current of 1000.0 amp need to be passed through a molten AlF3 electrolysis cell to produce this amount of aluminum?

Which metal would NOT be a good sacrificial anode to inhibit the corrosion of iron by cathodic protection?

Electrolytic processes are used in a variety of applications.Which of the following does NOT involve electrolysis?

All are methods used to inhibit corrosion in iron EXCEPT

How many kilograms of aluminum metal can be produced by the electrolysis of Al2O3 using a current of 125.0 amps for 18.0 hours?

If 15.0 g of aluminum from an empty soda can could be used as an anode of a battery, how long could it supply a current of 15.0 amps?

Chromium often is electroplated on other metals and even plastics to produce a shiny metallic appearance.How many grams of chromium would plate out from a solution of Cr(NO3) 3 when 10.0 amps of current are passed through the electrolytic cell for 5.36 hours?

Magnesium metal is purified by electrolysis.How much magnesium metal could be produced from magnesium chloride by applying a current of 10.0 amps at the appropriate negative potential for 12.0 hours?

Suppose the redox reaction in a certain zinc-carbon battery is Zn + 2 MnO2 +2 NH4 Cl →\rightarrow→ MN2 O3 + Zn(NH3 ) 2 CL2 + H2 O.The battery is rated at 0.75 W • hr at 1.5 V.How many grams of zinc must be oxidized to deliver this much electrical energy?

Applying a current to a rechargeable battery converts it from ______cell to_____ cell.

If, in using a lead-acid battery to start a car, 1.00 gram of Pb is consumed on the anode, how long will it take to recharge the battery using a current of 0.500 amps to turn the PbSO₄ that was produced back into Pb?

How long would it take to electroplate a trumpet with 47.9 g of silver at a constant current of 2.50 amps using AgNO₃?

A roll of Reynolds Wrap aluminum foil contains 1.57 kg of aluminum.For how long would a current of 1000.0 amp need to be passed through a molten AlF₃ electrolysis cell to produce this amount of aluminum?

How many kilograms of aluminum metal can be produced by the electrolysis of Al₂O₃ using a current of 125.0 amps for 18.0 hours?

Chromium often is electroplated on other metals and even plastics to produce a shiny metallic appearance.How many grams of chromium would plate out from a solution of Cr(NO₃) ₃ when 10.0 amps of current are passed through the electrolytic cell for 5.36 hours?

Suppose the redox reaction in a certain zinc-carbon battery is Zn + 2 MnO₂ +2 NH₄ Cl $\rightarrow$ MN₂ O₃ + Zn(NH₃ ) 2 CL₂ + H₂ O.The battery is rated at 0.75 W _• hr at 1.5 V.How many grams of zinc must be oxidized to deliver this much electrical energy?

Applying a current to a rechargeable battery converts it from __cell to_ cell.