Free Practice Quiz Question List

12/14 Chemical Equilibrium Online Quiz Questions

Use this free practice quiz with 20 questions to review 12/14 Chemical Equilibrium, test your knowledge, and prepare for your next test or exam.

20 questions

True or false

1 point

True or false: Chemical equilibrium is dynamic because the forward and reverse reactions continue even though the macroscopic concentrations remain constant.

A
True
B
False

Choose one

1 point

Which statement best describes the effect of a catalyst on a system already capable of reaching equilibrium?

A
It increases the equilibrium constant.
B
It helps the system reach equilibrium more quickly without changing the equilibrium composition.
C
It shifts the equilibrium toward products.
D
It makes the reverse reaction stop.

Written response

1 point

What term describes a reversible reaction state in which the forward and reverse reactions occur at equal rates while macroscopic concentrations remain constant?

Fill in the blank

1 point

When an equilibrium constant is much greater than 1, the equilibrium composition favors .

Choose all

1 point

Which two statements correctly describe a reversible reaction at equilibrium? Select all that apply.

A
The forward and reverse reaction rates are equal.
B
The reactant and product concentrations must be equal.
C
Particles continue to undergo forward and reverse reactions.
D
All reactants have necessarily been consumed.

Choose one

1 point

For $\ce{N2(g) + 3H2(g) <=> 2NH3(g)}$ , what is the expected equilibrium response when the volume of the closed vessel is decreased at constant temperature?

A
It shifts left because pressure decreases.
B
It does not shift because volume has no effect on gases.
C
It shifts right toward ammonia.
D
It shifts right because the reaction becomes faster, not because of the mole count.

True or false

1 point

True or false: The reaction quotient Q is calculated only after a system has reached equilibrium.

A
True
B
False

Written response

1 point

For $\ce{N2O4(g) <=> 2NO2(g)}$ , calculate $Q_c$ when $[\ce{NO2}]=0.200\,\mathrm{M}$ and $[\ce{N2O4}]=0.0500\,\mathrm{M}$ . Enter the numerical value of $Q_c$ .

Fill in the blank

1 point

In an introductory equilibrium-constant expression, pure and pure liquids are omitted because their activities are effectively constant.

Choose all

1 point

For $\ce{N2(g) + 3H2(g) <=> 2NH3(g)}$ , which two changes produce the stated correct effects? Select all that apply.

A
Adding $\ce{N2}$ to $\ce{N2(g) + 3H2(g) <=> 2NH3(g)}$ shifts the equilibrium right.
B
Adding $\ce{NH3}$ to that system shifts the equilibrium right.
C
Removing $\ce{NH3}$ shifts the equilibrium left.
D
Adding an inert gas at constant volume does not shift the equilibrium.

Choose one

1 point

Which equilibrium-constant expression is correct for $\ce{CaCO3(s) <=> CaO(s) + CO2(g)}$ ?

A
$K_p=P_{\ce{CaCO3}}P_{\ce{CaO}}/P_{\ce{CO2}}$
B
$K_p=P_{\ce{CO2}}$
C
$K_p=P_{\ce{CaO}}P_{\ce{CO2}}$
D
$K_p=1/P_{\ce{CO2}}$

Open ended

1 point

For $\ce{2HI(g) <=> H2(g) + I2(g)}$ , an initially pure HI sample has $[\ce{HI}]_0=0.500\,\mathrm{M}$ , $[\ce{H2}]_0=0$ , and $[\ce{I2}]_0=0$ . Explain how to construct the Change and Equilibrium rows of an ICE table using a single variable $x$ , and justify the stoichiometric coefficients in your entries.

Choose one

1 point

Which disturbance changes the numerical value of the equilibrium constant for a given reaction?

A
Changing the concentration of a reacting species at constant temperature.
B
Changing the temperature of the system.
C
Adding an inert gas at constant volume.
D
Adding a catalyst.

Written response

1 point

For $\ce{2HI(g) <=> H2(g) + I2(g)}$ , $K_c=0.0200$ , and the initial concentrations are $[\ce{HI}]_0=0.500\,\mathrm{M}$ , $[\ce{H2}]_0=0\,\mathrm{M}$ , and $[\ce{I2}]_0=0\,\mathrm{M}$ . Using an ICE table, calculate $x$ in $[\ce{HI}]_{eq}=0.500-2x$ . Enter $x$ in molarity rounded to four significant figures; the tolerance is 0 M.

Choose one

1 point

Which statement best describes a reversible reaction at dynamic equilibrium?

A
The reaction has stopped completely.
B
The forward and reverse reaction rates are equal.
C
The reactant and product concentrations must be equal.
D
All reactants have been consumed.

Choose one

1 point

For the reaction $\ce{2SO2(g) + O2(g) <=> 2SO3(g)}$ , which expression correctly represents $K_c$ ?

A
$K_c=\frac{[\ce{SO2}]^2[\ce{O2}]}{[\ce{SO3}]^2}$
B
$K_c=\frac{[\ce{SO3}]}{[\ce{SO2}][\ce{O2}]}$
C
$K_c=\frac{[\ce{SO3}]^2}{[\ce{SO2}]^2[\ce{O2}]}$
D
$K_c=\frac{[\ce{SO3}]^2}{[\ce{SO2}][\ce{O2}]^2}$

Choose one

1 point

For $\ce{N2O4(g) <=> 2NO2(g)}$ , $K_c=0.200$ , $[\ce{NO2}]=0.200\,\mathrm{M}$ , and $[\ce{N2O4}]=0.0500\,\mathrm{M}$ . In which direction will the net reaction proceed?

A
Toward N₂O₄, the reactant
B
Toward NO₂, the product
C
In neither direction; the system is at equilibrium
D
In an unpredictable direction because only $K$ matters

Choose one

1 point

For $\ce{N2(g) + 3H2(g) <=> 2NH3(g)}$ , what shift occurs when the volume of the container is decreased at constant temperature?

A
Left, because higher pressure favors more gas particles
B
Left, because ammonia is a reactant
C
There is no shift because pressure does not affect equilibrium
D
Right, because the product side has fewer moles of gas

True or false

1 point

True or false: At constant temperature, changing the concentration of a reactant changes the value of the equilibrium constant $K$ .

A
True
B
False

Written response

1 point

For $\ce{CaCO3(s) <=> CaO(s) + CO2(g)}$ , the equilibrium partial pressure of $\ce{CO2}$ is $0.50\,\mathrm{atm}$ . What is the numerical value of $K_p$ ?