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WorksheetsEquilibrium & Le Chatelier's Principle
Total questions: 35
Worksheet time: 3hrs 51mins
Which is the correct equilibrium constant expression for the following reaction?
Fe2O3(s) + 3H2(g) —> 2 Fe(s) + 3H2O(g)
K = [H2O]3 / [H2]3
K = [Fe2O3] [H2]3 / [Fe]2[H2O]3
K = [Fe]2[H2O]3 / [Fe2O3] [H2]3
K= [Fe] [H2O] / [Fe2O3] [H2]
K = [H2] / [H2O]
The equilibrium constant expression for the reaction 2BrF5(g) —> Br2(g) + 5 F2(g) is
Kc = [Br2] [F2] / [BrF5]
Kc = [BrF5]2 / [Br2][F2]5
Kc = [Br2] [F2]5 / [BrF5]2
Kc = 2[BrF5]2 / ([Br2] × 5[F2]5)
Kc = [Br2] [F2]2 / [BrF5]5
The equilibrium between carbon dioxide gas and carbonic acid is very important in biology and environmental science. CO2(g) + H2O(l) —> H2CO3(aq)
Which one of the following is the correct equilibrium constant expression (Kc) for this reaction?
Kc= 1/ [H2CO3]
Kc= [CO2]/ [H2CO3]
Kc= [H2CO3] / [CO2]
Kc= [CO2] [H2O] / [H2CO3]
Kc= [H2CO3] / [CO2] [H2O]
Calculate Kc for the reaction 2 HI(g) —> H2(g) + I2(g) given that the concentrations of each species at equilibrium are as follows: [HI] = 0.85 mol/L, [I2] = 0.60 mol/L, [H2] = 0.27mol/L.
0.19
0.22
4.5
5.25
160
A chemical reaction in which products can react to re-form reactants is known as a(n)
reforming reaction
reversible reaction.
buffered reaction
stoichiometric reaction.
For any reaction at chemical equilibrium, the concentrations of products and reactants
are equal.
change
remain unchanged
decrease
A very high value for K indicates that
reactants are favored.
products are favored.
equilibrium is reached slowly.
equilibrium has been reached
This symbol indicates that a reaction is _____
reversible
irreversible
Around what time does the reaction reach equilibrium?
25 min
70 min
45 min
80 min
Changes in pressure will only affect substances that are in the ______ state.
solid
gas
liquid
Which of the two graphs reaches equilibrium?
Neither
The left
Both
The right
Which of the following is NOT true at equilibrium?
The concentrations of reactants and products do not change.
The forward and reverse reactions proceed at the same rate.
The concentration of the reactants is equal to the concentration of the products.
The forward and reverse reactions continue to occur.
The following factors affect the position of equilibrium EXCEPT
Concentration
State of Matter
Temperature
Pressure
Select all of the statements that are always correct about dynamic equilibrium
established when the product and reactant concentrations are equal
achieved when the forward and reverse reaction rates are same
established when the concentration of reactants is unchanging
achieved when the concentration ratio of reactants to products becomes stable
achieved when the forward and reverse reactions stop occurring
Given the equation representing a reaction:
N2O4(g) ⇌ 2NO2(g)
Which statement describes this reaction at equilibrium?
The concentration of N2O4(g) must equal the concentration of NO2(g).
The rate of the forward and reverse reaction is the same
The rate of the forward reaction is greater than the rate of the reverse reaction.
The rate of the reverse reaction is greater than the rate of the forward reaction.
What states of matter are omitted when writing Keq expressions?
solids and liquids
aqueous solutions and gas
solids, liquids, aqueous solutions and gases
aqueous solutions & liquids
When Keq < 1,
There are more products than reactants when the reaction reached equilibrium.
There are more reactant than products when the reaction reached equilibrium.
The amount of reactants is equal to the amount of products.
What is the Keq expression for this reaction?
2 NO(g) + O2(g) ⇌ 2 NO2(g)
Kc = [NO2]2 / [NO]2 [O2]
Kc = [NO]2 [O2] / [NO2]2
Kc = [NO]2 [O2] [NO2]2
Kc = [NO2]2 / [NO]2 + [O2]
The following reaction :
SO2 (g) + NO2 (g) ⇌ SO3 (g) + NO (g)
established equilibrium and was found to contain
0.40 M SO3 , 0.30 M NO,
0.15 M NO2 , and 0.20 M SO2.
Calculate the equilibrium constant for this reaction.
4.0
.42
.25
1.0
Calculate [H2O] if Keq = 1.2,
[CO2] = 0.846M, and [CH4]= 0.0713M
4CuO(s) +CH4(g) ⇌ CO2(g)+4Cu(s) +2H2O(g)
0.101 M
0.318 M
0.0102 M
3.77 M
How would the equilibrium shift in the reaction CH4 (g) + 2 H2S (g) <--> CS2 (g) + 4 H2 (g) if the concentration of CH4 was DECREASED?
Left ; toward reactants
Right ; toward products
no change
How would the equilibrium shift in the reaction CH4 (g) + 2 H2S (g) <--> CS2 (g) + 4 H2 (g) if the concentration of H2S was DECREASED?
Left ; toward reactants
Right ; toward products
no change
How would the equilibrium shift in the ENDOTHERMIC reaction CH4 (g) + 2 H2S (g) <--> CS2 (g) + 4 H2 (g) if the temperature was INCREASED?
Left ; toward reactants
Right ; toward products
no change
Which location would generate the most products for an exothermic reaction?
On a table at room temperature
In an oven at a higher temperature
On ice at a lower temperature
How would the equilibrium shift in the reaction CH4 (g) + 2 H2S (g) <--> CS2 (g) + 4 H2 (g) if the concentration of CS2 was INCREASED?
Left ; toward reactants
Right ; toward products
no change
How could volume be changed to favor products in the reaction CH4 (g) + 2 H2S (g) <--> CS2 (g) + 4 H2 (g)
Decrease V
Increase V
impossible
When does Q = K
At equilibrium
When there are more products
When there are more reactants
When is Q < K
At equilibrium
When there are more products
When there are more reactants
When is Q > K
At equilibrium
When there are more products
When there are more reactants
Which reaction would shift toward products if temperature was increased
H2 + Cl2 <--> 2 HCl + 49.7 kJ
2 NH3 + 37.2 kJ <--> N2 + 3 H2
CO + H2O <--> CO2 + H2 + 27.6 kJ
Which reaction would shift toward reactants if volume was decreased
2 H2O (g) + N2 (g) <--> 2 H2 (g) + 2 NO (g)
SiO2 (s) + 4 HF (g) <--> SiF4 (g) + 2 H2O (g)
CO (g) + H2 (g) <--> C (s) + H2O (g)
How would the equilibrium change for the reaction 4 HCl (g) + O2 (g) <--> 2 H2O (g) + 2 Cl2 (g) if volume was INCREASED
Right ; toward products
Left ; toward reactants
no change
How would the equilibrium change for the reaction 4 HCl (g) + O2 (g) <--> 2 H2O (g) + 2 Cl2 (g) if a catalyst was added
Right ; toward products
Left ; toward reactants
no change
How would the equilibrium change for the reaction 2 HgO (s) <--> Hg (l) + O2 (g) if more HgO was ADDED
Right ; toward products
Left ; toward reactants
no change because HgO is a solid
How would the equilibrium change for the reaction 2 HgO (s) <--> Hg (l) + O2 (g) if the pressure INCREASED
Right ; toward products
Left ; toward reactants
no change
