Chemistry

Chemical Equilibrium and Stoichiometry

103 Questions

Chemical equilibrium and stoichiometry questions cover equilibrium constants, percent yield, and the Haber process. These concepts test your ability to calculate reaction outcomes and purity. Practice these to excel in physical chemistry sections of competitive tests.

Equilibrium constant calculationsStoichiometric yieldHaber processPercent purityHomogenous equilibrium

Chemical Equilibrium and Stoichiometry Questions

Multiple choice

What is the equation for the equilibrium constant of a chemical reaction?

  1. K = [products]/[reactants]

  2. K = [reactants]/[products]

  3. K = ln([products]/[reactants])

  4. K = ln([reactants]/[products])
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The equilibrium constant of a chemical reaction is equal to the ratio of the concentrations of the products to the concentrations of the reactants, at equilibrium.

Multiple choice

What is the equation for the Raoult's law?

  1. P_total = P_A + P_B

  2. P_total = P_A - P_B

  3. P_total = P_A * P_B

  4. P_total = P_A / P_B
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Raoult's law states that the total vapor pressure of a solution is equal to the sum of the vapor pressures of the pure components of the solution.

Multiple choice

What is the equation for the Henry's law?

  1. P = k_H * X

  2. P = k_H / X

  3. P = X / k_H

  4. P = 1 / (k_H * X)
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

Henry's law states that the partial pressure of a gas in a solution is proportional to the mole fraction of the gas in the solution.

Multiple choice

The equilibrium equation of a structure is:

  1. [K]{U} = {F}

  2. [K]{U} = 0

  3. [M]{U} = {F}

  4. [M]{U} = 0
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The equilibrium equation of a structure is [K]{U} = {F}, where [K] is the stiffness matrix, {U} is the displacement vector, and {F} is the force vector.

Multiple choice

The equilibrium constant for a chemical reaction is defined as:

  1. The ratio of the concentrations of the reactants to the concentrations of the products.

  2. The ratio of the partial pressures of the reactants to the partial pressures of the products.

  3. The ratio of the activities of the reactants to the activities of the products.

  4. All of the above.
Reveal answer Fill a bubble to check yourself
D Correct answer
Explanation

The equilibrium constant for a chemical reaction is defined as the ratio of the concentrations of the reactants to the concentrations of the products, the ratio of the partial pressures of the reactants to the partial pressures of the products, and the ratio of the activities of the reactants to the activities of the products.

Multiple choice

What is the atom economy of the following reaction? $$C_6H_6 + 3Cl_2 → C_6H_6Cl_6$$

  1. 18.2%

  2. 27.3%

  3. 36.4%

  4. 45.5%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The atom economy of the reaction is calculated as follows: $$Atom economy = rac{Molecular weight of C_6H_6Cl_6}{Molecular weight of C_6H_6 + 3Cl_2} = rac{290.8}{78.1 + 213.0} = 0.182$$ Therefore, the atom economy of the reaction is 18.2%.

Multiple choice

What is the atom economy of the following reaction? $$2C_2H_5OH + 3O_2 → 4CO_2 + 6H_2O$$

  1. 90.9%

  2. 81.8%

  3. 72.7%

  4. 63.6%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The atom economy of the reaction is calculated as follows: $$Atom economy = rac{Molecular weight of 4CO_2 + 6H_2O}{Molecular weight of 2C_2H_5OH + 3O_2} = rac{176.0 + 108.0}{92.1 + 96.0} = 0.909$$ Therefore, the atom economy of the reaction is 90.9%.

Multiple choice

What is the atom economy of the following reaction? $$CH_4 + 2O_2 → CO_2 + 2H_2O$$

  1. 33.3%

  2. 44.4%

  3. 55.5%

  4. 66.6%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The atom economy of the reaction is calculated as follows: $$Atom economy = rac{Molecular weight of CO_2 + 2H_2O}{Molecular weight of CH_4 + 2O_2} = rac{44.0 + 36.0}{16.0 + 64.0} = 0.333$$ Therefore, the atom economy of the reaction is 33.3%.

Multiple choice

What is the atom economy of the following reaction? $$2C_6H_5CH_3 + 3O_2 → 12CO_2 + 6H_2O$$

  1. 77.8%

  2. 88.9%

  3. 99.0%

  4. 110.1%
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The atom economy of the reaction is calculated as follows: $$Atom economy = rac{Molecular weight of 12CO_2 + 6H_2O}{Molecular weight of 2C_6H_5CH_3 + 3O_2} = rac{528.0 + 108.0}{182.2 + 96.0} = 0.778$$ Therefore, the atom economy of the reaction is 77.8%.

Multiple choice

What is the equivalence point in Titration?

  1. The point at which the moles of reactants are equal

  2. The point at which the volumes of reactants are equal

  3. The point at which the concentrations of reactants are equal

  4. The point at which the pH of the solution is neutral
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

The equivalence point in Titration is reached when the moles of reactants are stoichiometrically equivalent, resulting in the complete reaction of both reactants.

Multiple choice

What is the role of an indicator in Titration?

  1. To signal the equivalence point

  2. To adjust the pH of the solution

  3. To catalyze the reaction between reactants

  4. To enhance the accuracy of the titration result
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

An indicator is used in Titration to visually signal the equivalence point by changing color, indicating the completion of the reaction.

Multiple choice

Which of the following ions is most likely to form a precipitate with magnesium ions (Mg+2) in seawater?

  1. Chloride ions (Cl-)

  2. Sulfate ions (SO42-)

  3. Carbonate ions (CO32-)

  4. Sodium ions (Na+)
Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Magnesium carbonate (MgCO3) is a common precipitate in seawater. This is because carbonate ions (CO32-) are abundant in seawater, and they react with magnesium ions (Mg+2) to form magnesium carbonate, which is insoluble in water.

Multiple choice

Which of the following ions is most likely to form a precipitate with barium ions (Ba+2) in seawater?

  1. Chloride ions (Cl-)

  2. Sulfate ions (SO42-)

  3. Carbonate ions (CO32-)

  4. Sodium ions (Na+)
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

Barium sulfate (BaSO4) is a common precipitate in seawater. This is because sulfate ions (SO42-) are abundant in seawater, and they react with barium ions (Ba+2) to form barium sulfate, which is insoluble in water.