WorksheetsChap 6: Chemical Equilibrium
Total questions: 56
Worksheet time: 1hrs 12mins
The forward reaction points towards the __________.
The forward reaction forms the substance __________.
The reverse reaction points towards the __________.
The reverse reaction forms the substance __________.
SO2 + O2 <−> SO3
If the concentration of SO2 is increased, the equilibrium of the reaction will shift ___________.
SO2 + O2 <−> SO3
If the equilibrium shifts to the right, the concentration of O2 will ___________.
SO2 + O2 <−> SO3
If the equilibrium shifts to the right, the concentration of SO3 will ___________.
SO2 + O2 <−> SO3
If the concentration of O2 is decreased, the equilibrium of the reaction will shift ___________.
SO2 + O2 <−> SO3
If the equilibrium shifts to the left, the concentration of SO3 will ___________.
SO2 + O2 <−> SO3
If the equilibrium shifts to the left, the concentration of SO2 will ___________.
heat + N2 + O2 <−> 2NO
If O2 is removed, the concentration of N2 will _______.
heat + N2 + O2 <−> 2NO
If NO is removed from the system, the concentration of N2 will _______.
N2 (g) + 3 H2 (g) <−> 2 NH3 (g)
If the pressure in the system is increased, _______ reaction will be favored.
N2 (g) + 3 H2 (g) <−> 2 NH3 (g)
If the pressure in the system is increased, which substance will increase in concentration?
N2 (g) + 3 H2 (g) <−> 2 NH3 (g)
If the pressure in the system is decreased, which substance will increase in concentration?
At elevated temperatures ammonium carbonate, NH2COONH4, is in equilibrium with NH3 and CO2 according to the equation;
NH2COONH4(s) ↔ 2 NH3(g) + CO2(g)
What is the equilibrium expression for this reaction?
K = 2 [NH3][CO2]
[NH2COONH4]
K = [NH3]2[CO2]
[NH2COONH4]
K = 2 [NH3][CO2]
K = [NH3]2[CO2]
Decreasing volume of container will
For the following reaction: H2(g) + Cl2 (g) ↔ 2HCl(g), calculate the concentration of HCl when Keq= 2.3x10-5, [H2]= 0.0056mol, [Cl2]= 0.0048mol.
6.2 x 10-10 M
2.5 x 10-5 M
1.1 M
1.2 M
PCl3 (g) + Cl2 (g) ↔ PCl5 (g) + energy
Which of the following causes an increase in the moles of PCl5 present at equilibrium shown?
decreasing the volume of the container
raising the temperature
adding a mole of He gas at constant volume
adding a mole of He gas at constant pressure
What kind of equilibrium does the reaction below show?
H2(g) +I2(g) ↔ 2HI(g)
Heterogeneous equilibrium, all the reactants and products are in the same physical state.
Homogeneous equilibrium, all the reactants and products are in the same physical state.
Heterogeneous equilibrium, the reactants and products are present in more than one physical state
Homogeneous equilibrium, the reactants and products are present in more than one physical state
H2(g)+Cl2(g)⇌2HCl(g)
The forward reaction is exothermic. What will happen to the equilibrium if the temperature is increased?
equilibrium shifts right
equilibrium shifts left
You cannot predict the effect
no change
An equilibrium constant with a value of 4.6 x 1015 indicates that at equilibrium
the reactants are favored.
the products are favored.
approximately equal concentrations of reactants and products are present.
When pressure decreases, in which direction does the equilibrium shift?
The equilibrium shifts in the direction that increases the number of moles of gas.
The equilibrium shifts in the direction that decreases the number of moles of gas.
The equilibrium does not shift.
The equilibrium shifts always shifts to the right.
The equilibrium shifts always shifts to the left.
For an endothermic reaction, increasing the temperature
does not shift the equilibrium since K is a constant.
increases the rate of the reverse reaction to form more reactants.
increases the rate of the forward reaction to form more products.
increases the rate of the reverse reaction to form more products.
For which of the following reactions does Kp = Kc?
3Fe(s) + 4H2O(g) ⇌ Fe3O4(s) + 4H2(g)
C(s) + H2O(g) ⇌ CO(g) + H2(g)
2SO2(g) + O2(g) ⇌ 2SO3(g)
H2(g) + I2(s) ⇌ 2HI(g)
What is the value for Kc if [CO] = 0.025, [H2] = 0.013 and [CH3OH] = 0.0028 for the following reaction?
CH3OH(g) ⇌ CO(g) + 2 H2(g)
0.12
9.1 × 10-7
6.6 × 102
1.5 × 10-3
8.6
Which of the following substances present in the chemical reaction would NOT be included in the equilibrium constant expression?
solvents
NaCl(s)
H2O(l)
NH4Cl(s)
all of these
For the following chemical equilibrium, Kp = 4.6 × 10-14 at 25 °C, find the value of Kc for this reaction at 25 °C.
2 Cl2(g) + 2 H2O(g) ⇔ 4 HCl(g) + O2(g)
Kc = 2.2 × 10-14
Kc = 4.6 × 10-14
Kc = 9.4 × 10-14
Kc = 1.9 × 10-15
Kc = 1.1 × 10-12
For the reaction PCl5 (g) → PCl3 (g) + Cl2 (g) Kc = 0.0454 at 261°C. If a vessel is filled with these gases such that the initial concentrations are [PCl5] = 0.25M, [PCl3] = 0.20 M, and [Cl2] = 2.25 M, in which direction will a reaction occur and why?
toward products because Q = 0.56
toward reactants because Q = 1.8
it is at equilibrium
toward reactants because Q = 0.0454
toward products because Q = 2.8
Consider the following reaction.
C(s) + H2O(g) ⇌ CO(g) + H2(g)
At equilibrium at a certain temperature, [H2O(g)] = 0.12 M, and [CO(g)] = [H2(g)] = 1.2 M. If suddenly these concentrations are increased by 0.50 M, which of the following is true?
Since Kc does not change, nothing happens.
more products are formed
more H2O(g) will be formed
Kc = 4.66
For the reaction: CH4(g) + 2 H2O(g) ⇔ CO2(g) + 4 H2(g) ΔH° = +190 kJ raise the temperature to 1200 K:
the temperature increases.
the ΔH° increases.
the reaction reacts to the right.
the reaction reacts to the left.
there is no change.
In a reaction at equilibrium involving only gases, a change in pressure of the reaction mixture shifts the position of equilibrium only when:
the reaction is exothermic as written
the gases are impure
the collision rate increases
heat is absorbed by the reaction proceeding to the right
the moles of gas are not equal on the two sides of the equation.
For the reaction: 3 Fe(s) + 4 H2O(g) ⇔ Fe3O4(s) + 4 H2(g) what is the effect of removing H2?
The Kp is decreased.
The reaction shifts to the right.
There is no change.
The reaction shifts to the left.
The Kp is doubled.
Consider the reaction: CH4(g) + 4 Cl2(g) ⇔ CCl4(l) + 4 HCl(g) ΔH° -398 kJ/mol The equilibrium is displaced to the right if:
the pressure is lowered
the temperature is raised
some hydrogen chloride is added
some carbon tetrachloride is removed
Consider the following reaction at a certain temperature.
2SO3(g) ⇌ 2SO2(g) + O2(g)
When the initial concentration of SO3(g) is 0.128 M, at equilibrium the concentration of oxygen gas is found to be 0.0130 M. Calculate Kc for this reaction.
8.45 x 10-4
1.47 x 10-3
7.64 x 10-5
1.62 x 10-2
For the formation of NO2, Kc = [NO2]/[NO][O2]1/2. At equilibrium in a 2.50 L container, there are 3.00 mol NO, 4.00 mol O2 and 22.0 mol NO2. The value of Kc is:
13.4
5.80
0.0116
33.6
Which of the following changes will increase the reaction rate?
an increase in the concentration of the products
allowing more time for the reaction
an increase in the concentration of reactants
all of the above
Which of the following is TRUE for a system that is in dynamic equilibrium?
The forward reaction goes to 100% completion.
The reaction rate of the forward reaction approaches zero.
The concentration of products is equal to the concentration of the reactants.
none of the above
Which of the following is TRUE of a system for which << 1?
It will take a long time to reach equilibrium.
It will take a short time to reach equilibrium.
The equilibrium favors the reverse reaction.
The equilibrium favors the forward reaction.
When writing the expression for an equilibrium constant, which type of substance is included?
solids
pure liquids
gases
all of the above
Le Chatelier's Principle states that:
a disturbing force must be applied to a system in order for it to reach equilibrium.
when a system at equilibrium is disturbed, a new equilibrium constant is established.
when a chemical system at equilibrium is disturbed, the system shifts in order to minimize the effect.
when a chemical system is at equilibrium it is no longer possible to alter the system.
What happens to the equilibrium position of an exothermic reaction when you remove heat?
shifts to the left
shifts to the right
does nothing
doubles
A chemical equilibrium exists when:
reactants are completely changed to products.
there are equal amounts of reactants and products.
the rate at which reactants form products becomes zero.
the rate at which reactants form products is the same as the rate at which products form reactants
What is non reversible reaction ?
Reaction occur in one way only
Reaction proceeds in only one direction
Reaction Occur slowly and reversible
Reaction proceed in both forward and reverse direction
What is a characteristic of a system in equilibrium except ?
Occurs only in closed system
Concentration of product and reactant not change
Concentration of product appearing per unit time
Rate of forward reaction equals the rate of reverse reaction
K=[CO] [H2] 3 / [CH4] [H2O]
K=[H2]3 [CO] /[CH4] [H2O]
K=[CO] [H2] 3 /[H2O] [CH4]
K=[H2]3[CH4] /[CO] H2O]
Determine whether the following reactions are homogeneous
3Fe(s)+4H2O(1)=Fe3O4(s)+4H2(g)
FeO(s) + CO(g) =Fe(s) +CO2(g)
2PCl3(g)+O2(g)=2POCl3(g)
Ag+(aq) +Fe2+(aq) =Ag(s) +Fe3+(aq)
Po2=867atm
Po2=865atm
Po2=785atm
Po2=782atm
Pcl2=2.94
Pcl2=1.98
Pcl2=2.43
Pcl2=1.86
Kp=2.0x10-5
Kp=1.2x5-3
Kp=1.5x10-5
Kp=3.2x10-6
3.2x10-6
Kc=4.1x10-4
Kc=3.1x10-2
Kc=2.6x10-6
The factors that effect a system at equilibrium except:
Caltalyst
Temperature
Pressure and volume
Mass
