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Chemistry 360
Spring 2015
Dr. Jean M. Standard
March 23, 2015
Problem Set 8
Good review problems in Engel & Reid (3rd Ed.): 6.3, 6.10, 6.11, 6.15, 6.21, 6.37, 6.41
1.
Consider the reaction between zinc metal and hydrochloric acid,
Zn (s) + 2 HCl ( aq)
H 2 ( g) + ZnCl2 ( aq) .
If the initial amounts present are 100.0 g Zn and 150.0 mL of 2.25 M HCl, determine the minimum and
maximum values
€ that are possible for the extent€of reaction ξ for this reaction.
2.
The equilibrium constant for the isomerization of cis-2-butene
to trans-2-butene is K eq = 2.07 at 400 K.
€
Determine the standard molar Gibbs free energy, ΔGR! , for the reaction at 400 K.
3.
Buckminsterfullerene, C60, is an icosohedral (soccer-ball) shaped molecule composed of hexagons and
!
pentagons of carbon atoms. For C60, the standard molar Gibbs free energy of formation, ΔG f , is 23.98 kJ/mol
at 25.0ºC. Write the balanced formation reaction for C60 and determine the equilibrium constant K eq for the
formation of C60.
€
4.
€
For the reaction
CO (g) + 3 H2 (g)
CH4 (g) + H2O (g) ,
determine an expression for the equilibrium constant in terms of the extent of reaction ξ when one mole of CO
gas is mixed with one mole of hydrogen gas.
5.
€
Nitrogen dioxide, NO2, dimerizes to form nitrogen tetroxide according to the reaction
2 NO 2 ( g)
N 2O 4 ( g) .
(a.) Using data from the appendix of your textbook, calculate the standard molar Gibbs free energy of reaction,
298 K.
ΔGR! , and the equilibrium
€ constant, K eq , at €
(b.) Calculate the extent of reaction ξ for this reaction if 1.0 mole of NO2 and 0.0 moles of N2O4 are present
initially. The equilibrium €
pressure is 1.5 bar.
€
2
6.
A mixture of diatomic nitrogen and diatomic hydrogen gas in a 1:3 molar ratio was passed over a catalyst to
form ammonia at 450°C. At a pressure of 10.13 atm, there was 2.04% by volume of ammonia gas formed.
Determine the equilibrium constant for the reaction
1
2
7.
N 2 ( g) +
( g)
NH 3 ( g) .
A 1.0 L reaction vessel€containing 0.233 moles of N2 and
€ 0.341 moles of PCl5 is heated to 250°C. The total
pressure once the system reaches equilibrium is 29.33 atm. Calculate the equilibrium constant for the reaction
PCl5 (g)
8.
3H
2 2
PCl3 (g) + Cl2 (g) .
Determine the equilibrium constant and extent of reaction for the dissociation of hydrogen gas at 3000 K and
1 atm,
H2 (g)
2 H (g) .
!
The standard molar Gibbs free energies of formation, ΔG f , of H2 and H at 3000 K are 0 and 46.01 kJ/mol,
respectively.
€