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General Chemistry Principles, Patterns, and Applications, 2011

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c.<br />

( ) + 6H 2O( g)<br />

CoCl2 s<br />

CoCl2 ×6H 2O( s);DH rxn = - 352 kJ / mol, DS rxn = - 899<br />

d. J/(mol·K)<br />

2PCl3 g<br />

e.<br />

DG f PCl 3<br />

f. ) = −558.5 kJ/mol<br />

5. The gas-phase decomposition of N 2 O 4 to NO 2 is an equilibrium reaction with K p = 4.66 × 10 −3 . Calculate the<br />

st<strong>and</strong>ard free-energy change for the equilibrium reaction between N 2 O 4 <strong>and</strong> NO 2 .<br />

6. The st<strong>and</strong>ard free-energy change for the dissolutio<br />

7. is 26.1 kJ/mol. What is the equilibrium constant for this process at 25°C?<br />

8. Ammonia reacts with water in liquid ammonia solution (am) according to the equatio<br />

9. change in enthalpy for this reaction is 21 kJ/mol, <strong>and</strong> ΔS° = −303 J/(mol·K). What is the equilibrium constant<br />

for the reaction at the boiling point of liquid ammonia (−31°C)?<br />

10. At 25°C, a saturated solution of barium carbonate is found to have a concentration of [Ba 2+ ] = [CO 2− 3 ] =<br />

5.08 × 10 −5 M. Determine ΔG° for the dissolution of BaCO 3 .<br />

11. Lead phosphates are believed to play a major role in controlling the overall solubility of lead in acidic soils.<br />

One of the dissolution reactions i<br />

12. log K = −1.80. What is ΔG° for this reaction?<br />

13. The conversion of butane to 2-methylpropane is an equilibrium process with ΔH° = −2.05 kcal/mol <strong>and</strong> ΔG° =<br />

−0.89 kcal/mol.<br />

a. What is the change in entropy for this conversion?<br />

b. Based on structural arguments, are the sign <strong>and</strong> magnitude of the entropy change what<br />

you would expect? Why?<br />

c. What is the equilibrium constant for this reaction?<br />

14. The reaction of CaCO 3 (s) to produce CaO(s) <strong>and</strong> CO 2 (g) has an equilibrium constant at 25°C of 2 × 10 −23 .<br />

Values<br />

( ) + O2( g) 2POCl3( g);<br />

( ) = - 272.4 kJ / mol, DG f (POCl 3<br />

n K4Fe( CN )6× H2O s<br />

n NH 3 g<br />

a. What is ΔG° for this reaction?<br />

( ) 4K + ( aq) + Fe CN<br />

( )64 - aq<br />

( ) + H2O( am) NH 4 + ( am) +OH - am<br />

of DH<br />

f are<br />

s Pb3(PO4)2 s<br />

3Pb2 + aq<br />

( ). The<br />

( ) + 4H + ( aq)<br />

( ) + 2H 2PO4 - aq<br />

( ) + H2O( l)<br />

( ), for which<br />

as follows: CaCO 3 , −1207.6 kJ/mol; CaO, −634.9 kJ/mol; <strong>and</strong> CO 2 , −393.5 kJ/mol.<br />

Saylor URL: http://www.saylor.org/books<br />

Saylor.org<br />

1687

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