Download Chapter 7 Review

Chapter 7 Review
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1.
Write an example of solubility equilibrium, phase equilibrium and chemical reaction equilibrium.
For example: CaCO3(s) <---> CaO(s) + CO2(g) = chemical reaction equilibrium (3)
2.
Describe why a chemical equilibrium is dynamic rather than a static equilibrium? (1)
3.
List three conditions that must be met for a system to be considered to be in a state of dynamic
equilibrium. (3)
4.
Using the equation: 2 NH3(g) <---> N2(g) + 3 H2(g)
4.00 mol of ammonia gas are introduced into a 2.00 L
container and heated. At equilibrium, 2.50 mol of
ammonia remain in the container.
a) Use an ICE table to determine the equilibrium
concentrations of nitrogen and hydrogen gas. (3)
b) Plot the concentrations of these gases on the graph
as the system moves from initial conditions to
equilibrium. (2)
c) Calculate the percent reaction at equilibrium. (2)
5.
Write equilibrium law (K) equations for the following:
a)
b)
c)
d)
e)
6.
CO(g) + 2 H2(g) <---> CH3OH(g)
2 HI(g) <---> N2(g) + 3 H2(g)
2 H2S(g) + CH4(g) <---> 4 H2(g) + CS2(g)
2 H2O(l) <---> 2 H2(g) + O2(g)
3 Zn(s) + 2 CrBr3(aq) <---> 2 Cr(s) + 3 ZnBr2(aq)
For the reaction CO(g) + 2 H2(g) <---> CH3OH(g) + heat;
[CO(g)] = 0.025 mol/L, [H2(g) ] = 0.050 mol/L and [CH3OH(g)] = 0.0063 mol/L
a)
b)
c)
d)
e)
f)
determine K (2)
determine K’ (K for the reverse reaction) (2)
Will K change if any products or reactants are added to the reaction vessel? (1)
Will K change if temperature is increased? (1)
Will K change if the pressure is increased? (1)
If only CH3OH(g) is added to the vessel, will the same K value eventually be reached? (1)
7.
Le Châtelier’s Principle.
Stress system
Reaction:
Change
+ = forward
Ø = no change
— = reverse
C2H6(g) + energy <==> C2H4(g) + H2(g)
Explanation
change in concentration after
system has been stressed
C2H6(g)
C2H4(g)
change
in
Kc
H2(g)
Add C2H4(g)
Remove H2(g)
Add C2H6(g)
Increase Temp
Increase Pressure
Increase Volume
Add Catalyst
8.
The Haber Process.
a) Write the chemical reaction for the Haber process and write a K equation to describe it. (2)
b) Why was this reaction so important when it was developed back in 1909? (2)
c) How did Haber manage to keep this reaction moving forward to produce ammonia? (4)
9.
For the equation: N2(g) + 3 H2(g) <=====> 2 NH3(g) ,
K = 0.050
if [N2(g)] = 2.0 x 10-4 mol/L, [H2(g)] = 4.0 x 10-3 mol/L, and [NH3(g)] = 2.2 x 10-4 mol/L, determine
Q. In which direction must the reaction proceed to establish equilibrium? (4)
10.
Initially 2.0 mol/L of H2 and I2 are added to a reaction vessel at 448 ºC. If the equilibrium constant
is 50 at 448 ºC determine the equilibrium concentrations. (5)
H2 (g) + I2 (g) → 2 HI (g)
11.
Given:
2 CO2 (g) → 2 CO + O2 (g)
Keq = 6.4 x 10 -7 @ 200 K
If the initial concentration of the CO2 is 1.0 M determine the equilibrium concentration of all
species. (5)
12.
If 0.20 mol of hydrogen and 0.50 mol of iodine are initially introduced into a 0.500-L reaction
chamber, calculate the concentration of all entities at equilibrium. (5)
H2(g) + I2(g) <=====> 2 HI(g) ,
K = 46.0 at 490ºC
13.
If the solubility of AgBr is 8.8 x 10-7 mol/L, what is its Ksp? (2)
14.
If the solubility of Al(OH)3 is 3.2 x 10-9 mol/L, what is its Ksp? (2)
15.
What is the solubility, in mol/L, of AgC2H3O2 in a 0.45 mol/L solution of AgNO3 if the Ksp of
AgC2H3O2 is 2.5  10-3? (5)
16.
What is the solubility, in mol/L, of CaF2 in a 0.65 mol/L solution of NaF, if the Ksp of CaF2 is 4.9 
10-11? (5)
17.
If 45 mL of a 0.45 mol/L solution of AgNO3 was mixed with 85 mL of a 1.35  10-2 mol/L solution
of NaCl, would a precipitate form? Calculate the ion product for the potential precipitate. The Ksp of
AgCl(s) is 1.8  10-10.. (5)
18.
If 365 mL of a 0.0054 mol/L solution of Pb(NO3)2 was mixed with 595 mL of a 6.34  10-4 mol/L
solution of KI, would a precipitate form? Calculate the ion product for the potential precipitate. The
Ksp of PbI2 is 7.9  10-9. (5)
19.
Calculate the standard Gibb's Free Energy change associated with the reaction between methanol
and oxygen to produce water vapour and carbon dioxide at SATP. (6)
20.
Estimate the boiling point of mercury, Hg(l). (5)