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Exam 2 ReviewExam 2 Review


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Basic Electro-chemistry

Potpourri Liquids andSolids

Properties ofSolutions

100100 100100 100100 100100

200200 200200 200200 200200

300300 300300 300300 300300

400400 400400 400400 400400500500 500500 500500 500500

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100:100: Basic ElectrochemistryBasic Electrochemistry

F2(g) has a standard reduction potential of2.87 V and Cl2(g) has a standard

reduction potential of 1.33 V. Which gas

is a stronger oxidizing agent?

What is F2(g)


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A 1.0 M KMnO4 solution is electrolyzed.This species is reduced at the cathode.

What is MnO4?


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The reactions for a lead storage (car)battery are shown below.PbSO4 + H

+ + 2e Pb + HSO4 E = 0.40V

PbO2 + HSO4 + 3H+ +2e PbSO 4 + 2H2O E =

+1.60V

The net reaction has this potential.

What is Ecell = 2.00 V?


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A concentration cell is constructed usingPb2+ at 0.20 M and 0.020 M. Thispotential is measured in the cell.



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A Zn|Zn2+

(0.10 M)||Cu2+

(2.50 M)|Cu with1.0 L of soln in each half cell. After 10.0hr of drawing 10.0 A, determine the cellpotential.



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100:100: PotpourriPotpourri

In the Pourbaixdiagram on theright, whichconversions are

potentialindependentreactions?

What are: Mn2+ to Mn(OH)2(s) Mn(OH)2(s) to Mn(OH)3

(s)


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200:200: PotpouriPotpouri

The quinone/hydroquinone redox couplehas the following reduction reaction:

Q(aq) + 2H+ + 2e QH2(aq)

The slope of a plot of EQ/QH 2 versus pH forthis reaction has this value.

What -0.05916 V/pH unit?


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In an attempt to prevent corrosion, a steel(Fe) pipe is connected to a piece of Al,which can act as a sacrificial anode. Theobserved rate of Fe corrosion is not

slowed appreciable. Why?

What is the aluminum forms an oxide (Al2O3(s)) preventing

it from acting as a sacrificial anode?


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A certain weak acid, HA, has a density of 4.70 g/Lin the gas phase at a temperature of 25 C anda pressure of 1.00 atm. When 2.30 g of this acidis dissolved in enough water to make 0.100 L of

solution, the pH is found to be 2.00. This valueis the Ka for HA.What is 5.26 10

4


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100:100: Liquids & SolidsLiquids & Solids

You receive a shipment of oranges in themail that are arranged in a closestpacked structure. Closer examinationreveals that the structure has only

trigonal and tetrahedral holes. This is thearrangement of oranges in the closestpacked structure. (CCP or HCP)

What is the hexagonal closest packed arrangement?


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This phenomenon leads to the nonlineartrend in boiling points.

What is hydrogen bonding?


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Based on the heating curve for thismaterial below, by what factor is Hvap

larger than Hfus ?

-250

-200

-150

-100

-50

0

0 50 100 150 200

Time

Temperature(oC)

What is afactor of 6?


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On the right is the structureof an importantsuperconductor madefrom Y, Ba, Cu, and O.

Based on the structure,this is the formula ofYBCO.

What is YBa2Cu3O7?


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100:100: Properties of SolutionsProperties of Solutions

Pickling (converting a cucumber to apickle for example) relies on thisprocess.

What is osmosis?


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Raoults can be used to describe thevapor pressure of a mixture of twovolatile species. Use the relationship tosketch the vapor pressure as a function

of A when the Pvap of pure A is greaterthan pure B and the two liquids mixendothermically.

What is: ?


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For which of the following gases wouldHenrys law most accurately describethe relationship between partial pressureand mole fraction in an aqueous

solution: HNO3(g), HCl(g) or HCN(g)?

What is HCN?


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Since the lattice enthalpy of KCl(s) is 715kJ/mol, Hhyd for Cl is 406 kJ/mol and

Hhyd for K+ is 278 kJ/mol, the Hsoln

for KCl(s) has this value.

What is 31 kJ/mol?


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