NAME______Chem 241 Sp 2006

Helpful information:

NA = 6.022x1023 mol-1, Avogadro’s numberR =8.3145 JK-1mol-1,the gas constant

c = 3 x 108 m/s, the speed of lighte = 1.602 x 10-19 C, the charge of an electron

m = 9.11 x 10-31 kg, the mass of an electrono = 8.85 x 10-12C2J-1m-1, permittivity of vacuum

h = 6.6262 x 10-34 J•s, Planck’s constant

F = 96,500 Jmol-1V-1 Faraday’s constant1 J = 1kg•m2•s-2 = 6.24 x 1018eV

log[H+] = 2.3(ln[H+])

Hf (kJ.mol):Cl2(g), 0; Cl(g), +121; F2(g), 0; F(g), +79; Na(g), 108;

Avg. Bond energies (kJ/mol): Cl-Cl, 240; F-Cl, 249; O-O, 142; O=O, 494;

Ionic radii (pm): Na+, 116; Cs+, 181; Zn2+, 88; Mn2+, 90; Mn7+, 70;O2-, 126;Cl-,167; S2-, 170

Reduction potentials, Eo (V):

Fe3+(aq) + 3e−  Fe0(s) -0.04

MnO4−(aq) + 8 H+(aq) + 5 e− Mn2+(aq) + 4H2O(l)+1.70

Co3+(aq) + e−  Co2+ (aq) +1.82

Cl2(aq) + 2e−  2Cl−(aq) +1.36

MnO2(s) + 4 H+(aq) + 2 e− Mn2+(aq) + 2 H2O (l)+1.23

For full credit, you must show your work, or explain your reasoning.

1______2______3______4______5______6______7______8______9______10______

Total: (500 possible)______
1.Place the following in order of increasing ionic radius:

Ca2+K+Ga3+Zn2+

  1. Consider the following p-block compounds of hydrogen:

BH3HICH4H2S

  1. Place them in order of increasing homolytic bond energy for the E-H bond
  1. Place them in order of increasing Bronsted acidity
  1. The alkali and alkaline metals form salts with many common anions, including halides.
  2. Place these 0.1M aqueous solutions in order of increasing Bronsted acidity (least acidic to most acidic).

LiCl(aq)NaCl(aq)MgCl2(aq)CaO(aq)

  1. Balance this reaction between Mg(s) and O2(g):

____ Mg(s) + _____O2(g) 

  1. The hydrogen-containing compounds of different elements, E-H, can react with water.

Balance these equations.

  1. ___ LiH(s) +____H2O(l) 
  1. ___ SiH4(g) + ____ H2O(l) 
  1. ____ HCl(g) + ___H2O(l) 
  1. ____ NH3 (g) + ___H2O(l) 
  1. The use of H2 for fuel cells relies upon a ready supply of fuel (H2). Industrial production of H2 is achieved by reacting H2O(g) with a carbon source. The Steam reforming process uses CH4(g), while the water-gas reaction uses C(s). Write balanced equations for both of these reactions.
  1. Why must this H2 be purified prior to use in a fuel cell? Does this route of H2 production solve our energy dependence on fossil fuels?

  1. There are three isotope of hydrogen. Protium (1H), deuterium (2H), and tritium (3H). Each has use for various reasons in chemical research.
  1. Which of these hydrogen isotopes could give an NMR signal?
  1. Explain why in one or two sentences.
  1. Which of these isotopes are radioactive?
  1. Place the following salts in order of increasing solubility.

CaCO3CsClCsINa2SO4

  1. The silicate mineral shown below consists of a repeating array of the SiO4 tetrahedral building blocks, with cations for charge balance. Each tetrahedron shares two oxygens with neighboring tetrahedra, but the cations are not shown in this figure. What is the likely formula for this silicate mineral?

Ca(SiO3)Ca2(SiO4)Ca(SiO2)(OH)2Ca3(Si4O11)

  1. Match the following elements or compounds with their listed uses or form.

__a___CaCO3_____quartz

__b___Sr2+_____Lab-grade glassware

__c___Li+(C18HCO2-)_____Mono lake tufa towers

__d___SiO2_____zeolite

__e___C4H9MgCl_____grease

__f___Mg2+_____Salt substitute

__g___Zn(s)_____chlorophyll

__h___B2O3_____lab prep for H2

__i___Al3+_____color TV

__j___KCl_____Grignard

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