Electrochemistry Questions and Answers

In the Hall-Heroult process, a large electric current is passed through a solution of aluminum oxide (Al2O3) dissolved in molten cryolite (Na3AlF6), resulting in the reduction of the Al₂O3 to pure aluminum. Suppose a current of 6900. A is passed through a Hall-Heroult cell for 14.0 seconds. Calculate the mass of pure aluminum produced. Round your answer to 3 significant digits. Also, be sure your answer contains a unit symbol.

2. Consider the following chemical equations. Predict if the following solutions would conduct electricity weakly, strongly or not at all. a) KBr(s) → K+ (aq) + Br (aq) b) NH3(aq) + H₂O(1) NH(aq) + OH- (aq) c) C6H₁2O6(s) → C6H₁2O6 (aq)

Suppose a current of 0.530 A flows through a copper wire for 278. seconds. Calculate how many moles of electrons travel through the wire. Be sure your answer has the correct unit symbol and round your answer to 3 significant digits.

Suppose 620, mmol of electrons must be transported from one side of an electrochemical cell to another in 35.0 minutes. Calculate the size of electric current that must flow. Be sure your answer has the correct unit symbol and round your answer to 3 significant digits.

E Ag /Ag 2 Ag(s) + Fe²+ (aq) (1.0 M) = 2 Ag+ (aq) (1.0 M) + Fe(s) K = = +0.80 V Eº Fe²/Fe = -0.44 V At 25°C, calculate the free energy change and the equilibrium constant of the reaction above. AG° = kJ/mol

Suppose a current of 90. A flows through a copper wire for 139. seconds. Calculate how many moles of electrons travel through the wire. Be sure your answer has the correct unit symbol and round your answer to 2 significant digits.

Why is YOUR answer to #22 correct? Identify the TRUE statement(s) regarding standard reduction potentials that you based YOUR answer to #22 on. Select ALL that apply. (1 Point) * Reactions do not spontaneously occur if the difference in reduction potentials is equal to 0. If Ecell <0 then the reaction is NOT SPONTANEOUS. r Positive reduction potentials ALWAYS result in positive differences, thus the reaction is spontaneous. If Er cell is positive, then the reaction is SPONTANEOUS.

Which of the following statements about corrosion is true? Select all that apply. A. Connecting metal A to a more reactive metal will prevent or slow the corrosion of metal A because metal A serves as the anode. B. Seawater does not promote corrosion. C. Coating iron with zinc is a good way to prevent the iron from corroding. D. Oxidation on the surface of certain metals can prevent or slow corrosion of the metal. E. Connecting dissimilar metals is a good way to protect both metals against corrosion. Select 5 poi

certain half-reaction has a standard reduction potential Ered=+0.39 V. An engineer proposes using this half-reaction at the cathode of a galvanic cell that must provide at least 1.30 V of electrical power. The cell will operate under standard conditions. Vote for advanced students: assume the engineer requires this half-reaction to happen at the cathode of the cell. Is there a minimum standard reduction potential that the half-reaction used at yes, there is a minimum. the anode of this cell can have? If so, check the "yes" box and calculate the minimum. Round your answer to 2 decimal places. If there is no lower limit, check the "no" box. Is there a maximum standard reduction potential that the half-reaction used at the anode of this cell can have? If so, check the "yes" box and calculate the maximum. Round your answer to 2 decimal places. If there is no upper limit, check the "no" box. By using the information in the ALEKS Data tab, write a balanced equation. describing a half reaction that could be used at the anode of this cell. Note: write the half reaction as it would actually occur at the anode. no minimum O yes, there is a maximum. no maximum. 0 red red = Ov = 0-0 00 e™ X Ś ?

The following materials were used to construct the half-cells of a GALVANIC CELL: sodium sulfate (Na2SO4), zinc, zinc sulfate solution (ZnSO4), nickel, nickel (II) sulfate solution (NiSO4). Which of the following would they use as their ANODE electrode? Nickel Sodium sulfate (Na2SO4) Nickel (II) sulfate solution (NiSO4) Zinc sulfate solution (ZnSO4) Zinc

Suppose 0.880 mol of electrons must be transported from one side of an electrochemical cell to another in 212. seconds. Calculate the size of electric current that must flow. Be sure your answer has the correct unit symbol and round your answer to 3 significant digits.

Electroplating is a way to coat a complex metal object with a very thin (and hence inexpensive) layer of a precious metal, such as silver or gold. In essence the metal object is made the cathode of an electrolytic cell in which the precious metal cations are dissolved in aqueous solution. Suppose a current of 0.870 A is passed through an electroplating cell with an aqueous solution of AgNO3 in the cathode compartment for 77.0 seconds. Calculate the mass of pure silver deposited on a metal object made into the cathode of the cell. Round your answer to 3 significant digits. Also, be sure your answer contains a unit symbol.

Which of the following do you consider as the benefit of using citation and the appropriate style? You work within the academic norms. All of the choices O Evidence or expert witnesses support your argument.

Part B Each of the following is placed in a dialyzing bag and the bag is then immersed in distilled water. Which substances will be found inside the bag? Check all that apply. NaCl solution albumin mixture starch mixture Part C Consider a mixture of NaCl, albumin mixture, and starch mixtures in a dialyzing bag. The dialyzing bag is then immersed in distilled water. Which of the following actions should be taken to remove the most salt from the mixture?

A chemist fills a reaction vessel with 0.763 M lead (11) (Pb2+) aqueous solution, 0.637 M bromide (Br) aqueous solution, and 0.136 g lead (11) bromide (PbBr₂) solid at a temperature of 25.0°C. Under these conditions, calculate the reaction free energy AG for the following chemical reaction: Pb2+ (aq) +2 Br (aq) PbBr₂ (s) Use the thermodynamic information in the ALEKS Data tab. Round your answer to the nearest kilojoule.

An electrolyte is a substance that will conduct electricity when dissolved in water. A substance that conducts electricity well is a strong electrolyte. A substance that conducts electricity poorly is a weak electrolyte. In contrast, a substance that does not conduct electricity when dissolved in water is a nonelectrolyte. Watch the video about the electrolytic properties of sodium chloride, NaCl, and sugar. Part A Watch the animation, then check off the samples that will conduct electricity. Check all that apply. Solid NaCl NaCl solution Solid sugar Sugar solution

This chemical reaction is preformed using the same procedure it was before, but this time we are investigating the concept of mass conservation. To do this we must take note of the masses of ALL the substances throughout the course of the reaction. You will need to write a procedure explaining how you would perform this reaction to either prove or disprove the law of mass conservation. Take note of the following as you write your procedure: • The starting materials are provided as solids. • You should begin with 1-6 grams of each solid dissolved each in approximately 15 mL of water. • Remember that the solid produced in this reaction settles to the bottom of your glassware over time. E6 NB Q2 Homework Unanswered Write our a procedure that explains how you will perform the reaction and what data you will collect in order to help prove or disprove the law of mass conservation.

A half-cell consisting of a Mn(s) electrode in Mn²+ (aq) is connected to a half-cell consisting of a Ni(s) electrode in Ni²+ (aq). This produces a voltaic cell in the which the following overall reaction occurs. Mn(s) + Ni²+ (aq) → Mn²+ (aq) + Ni(s) Which half-cell is the oxidation half-cell? Which half-cell is the reduction half-cell? Which electrode (solid metal) is the cathode? Which electrode (solid metal) is the anode? What is the sign (+ or -) on the manganese electrode? What is the sign (+ or -) on the nickel electrode?

Which of the following processes is endothermic? A hot cup of coffee (system) cools on a countertop The chemical reaction in a "hot pack" often used to treat sore muscles The vaporization of rubbing alcohol The freezing of water

Which of the following atoms is paramagnetic? A) AI B) Ba C) Kr D) Zn E) Xe

Which of the following atoms is diamagnetic? A) Be B) B C) C D) O E) F

Through electrolysis, a student collects 11.3 g of hydrogen gas and 89.7 g of oxygen gas. The reaction was allowed to proceed to completion. What was the mass of water initially present? . Round your answer to the nearest tenth.

The quantity of heat of a body of matter absorbs or releases when it experiences a temperature change of 1 kelvin is the heat capacity of the body of matter True False

A chemist assembles the following electrochemical cell. One side of the cell contains a zinc electrode immersed in aqueous zinc nitrate solution. The other side of the cell contains an iron electrode immersed in aqueous iron(II) nitrate solution. In this reaction, zinc is the anode and iron is the cathode. Write equations showing the half-reactions that take place at each electrode. Include phase symbols. anode half-reaction: cathode half reaction:

A certain half-reaction has a standard reduction potential Ered=+1.16 V. An engineer proposes using this half-reaction at the cathode of a galvanic cell that must provide at least 0.60 V of electrical power. The cell will operate under standard conditions. Note for advanced students: assume the engineer requires this half-reaction to happen at the cathode of the cell. Is there a minimum standard reduction potential that the half-reaction used at the anode of this cell can have? If so, check the "yes" box and calculate the minimum. Round your answer to 2 decimal places. If there is no lower limit, check the "no" box. Is there a maximum standard reduction potential that the half-reaction used at the anode of this cell can have? If so, check the "yes" box and calculate the maximum. Round your answer to 2 decimal places. If there is no upper limit, check the "no" box. By using the information in the ALEKS Data tab, write a balanced equation describing a half reaction that could be used at the anode of this cell. Note: write the half reaction as it would actually occur at the anode.

AA and AAA batteries are called alkaline because; they are rechargeable batteries the redox reaction occurs in an acidic medium they are secondary batteries the redox reaction occurs in a basic medium

Which of the statements about cathodic protection of a metal pipe against corrosion is correct? The metal pipe is protected by attaching an active metal to make the pipe the cathode in an electrochemical cell The metal pipe is protected by coating the pipe with another metal whose standard reduction potential is less negative than that of the pipe The metal pipe is protected by attaching a dry cell to reduce any metal ions which might be formed The metal pipe is protected by attaching an active metal to make the pipe the anode in an electrochemical cell

Fill in the blanks. Just write the question number (i), (ii), (iii)....... in the answer box and give your answer next to the number. (i) The higher the pH, the corrosion. (ii) Rusting of iron requires both and water. (iii) Iron is coated with a thin layer of in galvanized iron. (iv) Standard hydrogen electrode (SHE) has this reduciton potential. (v) Salt bridge contains an electrolyte solution like

Use Nernst equation to calculate the potential for the following electrochemical cell at 25°C and 1 atm. (ROUND to 3 decimals; DO NOT INLCUDE UNITS) Pb (s) / Pb²+ (aq, 1.274M) || Cu²+ (aq, 1.132M)/ Cu (s) Given below standard reduction potentials: Cu²+ + 2e → Cu (s) Eº= 0.126 V Pb²+ + 2e → Pb (s) Eº= +0.340 V

Which of the following is a neutralization reaction? 2NO₂(g) → 2NO(g) + O₂(g) KCI (aq) + NaNO3(aq) → KNO3(aq) + NaCl(aq) HNO3(aq) + KOH(aq) → H₂(1) + KNO3(aq) H₂O(l) + SO3(g) → H₂SO4(aq) 4Na(s) + O₂(g) → 2Na₂O(s)

For the equilibrium 2 PH₂(g) Pp₂ = 0.289 atm, and PH 0.867 atm at 873 K. Calculate Kp. P₂(g) + 3 H₂(g), the equilibrium partial pressures are Pp PH

Which of the following sequences of resistivity is correct? The resistivity of a conductor < The resistivity of a semiconductor = The resistivity of an insulator The resistivity of a conductor < The resistivity of a semiconductor < The resistivity of an Insulator The resistivity of a conductor <The resistivity of a semiconductor > The resistivity of an insulator The resistivity of a conductor > The resistivity of a semiconductor > The resistivity of an Insulator

Sketch a galvanic cell based on the half-reactions shown below. (4 C) Al 3+(aq) + 3e- → Al(s) Ni 2+(aq) + 2e- → Ni(s) a. Label the anode and the cathode. b. Indicate where oxidation and reduction are occurring. c. Show the direction of flow of the electrons. d. Write a balanced ionic equation for the reaction

3Cu+ (ag) + Au3+ (aq)->3Cu²+(aq) + Au(s) A student studying the reaction represented above constructs a voltaic cell as shown in the diagram below. The cell contains an Au(s) electrode in a beaker containing 1.00 M Au(NO3)3(aq) and a Pt(s) electrode in a beaker containing 1.00 M CUNO3(aq) and 1.00 M Cu(NO3)2(aq). The standard reduction potentials associated with the cell are given in the following table. Half-reaction E° (V) Cu²+ (aq) + e→ Cu+ (aq) 0.16 Au³+ (aq) + 3 e → Au(s) 1.50 a. Calculate the value of the standard cell potential, E. b. Does the mass of the Pt(s) electrode increase, decrease, or remain the same as the cell operates? Justify your answer.

Enter electrons as e Use smallest possible integer coefficients. If a box is not needed, leave it blank. For the following electron-transfer reaction: 3I₂(s) + 2Al(s) → 6I- (aq) + 2Al³+ (aq) The oxidation half-reaction is: __+__→___+__ The reduction half-reaction is: __+__→___+__

Calculate Ecell for the following: 3 points H2O2 + Cr2O32- → O2 + Cr3+

Calculate the standard cell potential, E cell' for the equation Pb(s) + F₂ (g) → Pb2+ (aq) + 2F- (aq) Use the table of standard reduction potentials. E cell = __ V

Calculate the cell potential for the reaction as written at 25.00 °C, given that [Cr²+] = 0.778 M and [Fe²+] = 0.0100 M. Use the standard reduction potentials in this table. Cr(s) + Fe2+ (aq) = Cr²+ (aq)+Fe(s)

Calculate the standard potential, Eº, for this reaction from its equilibrium constant at 298 K. X(s) + Y4+ (aq) = X4+ (aq)+Y(s) K = 5.55 x 10-5 E =

What would the potential of a standard hydrogen electrode (S.H.E.) be under the given conditions? [H+] = = 0.15 M PH₂ = 2.2 atm T = 298 K

A current of 4.72 A is passed through a Pb(NO3)2 solution for 1.90 h. How much lead is plated out of the solution? mass of lead: ___ g

The chemist is able to set up the electrolytic cell successfully, and measures the current running through the circuit to be 1.60 A. How many moles of solid zinc will be created in 1 hour? (1F = 96,485 coulombs per mole of electrons)

Use the information in the ALEKS Data tab to sort the following chemical species by reducing power. species reducing power Al(s) choose one ✓ Ca(s) choose one ✓ Mg(s) choose one ✓ Ni(s) choose one✓

Elemental calcium is produced by the electrolysis of molten CaCl₂. 1. What mass of calcium can be produced by this process if a current of 8300 A is applied for 53 h? Assume that the electrolytic cell is 55 % efficient. Express your answer using two significant figures. 2. What is the minimum voltage needed to cause the electrolysis? Express your answer using three significant figures.

How many joules of heat are produced by the combustion of 2.50 liters of acetylene, C₂H2, stored in a container at a pressure of 20,000 mm of Hg (torr) and temperature of 30.0°C with excess oxygen gas? (△H combustion (ethylene) = 48.24 kj/g). The equation for the combustion of acetylene is: 2C₂H₂ (g) + 5O2(g) → 4CO2(g) + 2H₂O(g)

A galvanic cell was constructed with a nickel electrode that was dipped into 1.6 M NISO4 solution and a chromium electrode that was immersed into a solution containing Cr3+ at an unknown concentration. The potential of the cell was measured to be 0.501 V, with the chromium serving as the anode. The standard cell potential for this system was determined to be 0.487 V. What was the concentration of Cr3+ in the solution of unknown concentration? [Cr3+] = __________

The Nernst equation is one of the most important equations in electrochemistry. To calculate the cell potential at non-standard-state conditions, the equation is E = E˚-(2.303 RT/nF) * log10 where E is the potential in volts, Eº is the standard potential in volts, R is the gas constant, T is the temperature in kelvins, n is the number of moles of electrons transferred, and F is the Faraday constant, and is the reaction quotient. Using the common reference temperature, 25 °C or 298 K, the equation has the form E = E˚-[(0.0592)/n] log Q The reaction quotient has the usual form Q =[products]"/[reactants]" A table of standard reduction potentials gives the voltage at standard conditions, 1.00 M for all solutions and 1.00 atm for all gases. The Nernst equation allows for the calculation of the cell potential E at other conditions of concentration and pressure. For the reaction 2Co³+ (aq) + 2Cl-(aq)→2Co²+ (aq) + Cl₂ (g). Eº = 0.483 V what is the cell potential at 25°C if the concentrations are [Co³+] =0.598M, [Co²+]= 0.773M and [Cl-]= 0.890M and the pressure of Cl₂ is PCl2 = 5.30 atm ? Express your answer with the appropriate units.

A galvanic cell is constructed by wiring a vanadium electrode bathed in 1.0 M V^2+ (aq) to a mercury electrode bathed in 1.0 M Hg^2+ (aq), with the two solutions connected by a salt bridge. Consider the two half reactions listed below. What is the cell voltage for this device? V^2+(aq) + 2e^- --->V (s) E° = -1.130 V vs SHE Hg^2+(aq) + 2e^- --->Hg (l) E° = +0.911 V vs SHE Select one: a. -2.041 V b. +2.041 V c. -1.020 V d. +0.219 v e. -0.219 V

Molecules that are easily reduced and oxidized can be used like batteries to shuttle charge (energy) from one reaction to the next. a) True b) False

QUESTION: Will a reaction happen? Why? Cu (s) + FeSO4 (aq) → No reaction happens because Copper is more active than the Sulfate in the compound. No reaction happens because Copper is less active than the Sulfate in the compound. Yes, a reaction happens because Copper is more active than the Iron in the compound. Yes, a reaction happens because Copper is less active than the Iron in the compound. No reaction happens because Copper is more active than the Iron in the compound. Yes, a reaction happens because Copper is less active than the Sulfate in the compound. No reaction happens because Copper is less active than the Iron in the compound. Yes, a reaction happens because Copper is more active than the Sulfate in the compound.