Chemical Equilibrium (Lesson)

Multiple Choice

Which of the following does NOT describe an endothermic reactions?

• absorption of energy

• ΔH > 0

• H_reactant < H_product

• -ΔH

Match

Match the following.

• ΔH > 0

• ΔH < 0

• Endothermic

• Exothermic

Endothermic

Exothermic

+ΔH

–ΔH

• Endothermic

• Exothermic

• +ΔH

• –ΔH

Multiple Choice

Ag⁺(aq) + Cl^-(aq) $$\rightarrow$$ AgCl(s)

• Increase in entropy

• Decrease in entropy

• At equilibrium

Multiple Choice

A gas condenses.

• Increase in entropy

• Decrease in entropy

• At equilibrium

Multiple Choice

Sweat evaporating.

• Increase in entropy

• Decrease in entropy

• At equilibrium

Match

Match the following

• $$\Delta$$ S_univ>0

• $$\Delta$$ S_univ<0

• ΔS_univ=0

spontaneous

non-spontaneous

equilibrium

• spontaneous

• non-spontaneous

• equilibrium

Match

Match the following

• $$\Delta$$ G<0

• $$\Delta$$ G>0

• ΔG=0

spontaneous

non-spontaneous

equilibrium

• spontaneous

• non-spontaneous

• equilibrium

Multiple Choice

When $$\Delta$$ G approaches 0 which means that there is no free energy available to do useful work, does it mean the reaction stopped?

• YES

• NO

Multiple Choice

∆H° > 0 and ∆S° < 0

• Spontaneous

• Nonspontaneous

• Spontaneous at high temperatures

• Spontaneous at low temperatures

Multiple Choice

∆H° < 0 and ∆S° < 0

• Spontaneous

• Nonspontaneous

• Spontaneous at high temperatures

• Spontaneous at low temperatures

Multiple Choice

Which of the following is TRUE about chemical equilibrium in a reaction?

• the rates of the forward and backward reactions are directly proportional

• forward and reverse reaction rates become equal

• reaction has stopped

• the concentrations of the reactant and product species are inversely proportional

Multiple Choice

If Q = $$\frac{\left[C\right]^x\left[D\right]^y}{\left[A\right]^m\left[B\right]^n}$$ and the equation is 4NH₃(g) + 7O₂(g) ⇌ 4NO₂(g) + 6H₂O(g). What is the value of x?

• 1

• 4

• 3

• 6

Multiple Choice

If Q =  $\frac{\left[C\right]^x\left[D\right]^y}{\left[A\right]^m\left[B\right]^n}$ and the equation is 4NH₃(g) + 7O₂(g) ⇌ 4NO₂(g) + 6H₂O(g). What is the value of n?

• 7

• 2

• 3

• 6

Open Ended

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A. 2SO₂(g) + O₂ (g) ⇌ 2SO₃ (g)

B. C₄H₈(g) ⇌ 2C₂H₄(g)

C. 2C₄H₁₀(g) + 13O₂ (g) ⇌ 8CO₂(g) + 10H₂O(g)

Multiple Choice

Which of the following phase of matters are disregarded in writing reaction quotient?

• gasses

• aqueous

• solid

• liquid

• both solid and liquid

Multiple Choice

Which of the following is TRUE when reaction proceeds toward equilibrium in the forward direction?

• reactant concentrations increases

• product concentration increases

• reaction quotient consequently decreases

• denominator of Q_c increases

Multiple Choice

Which of the following is TRUE when the reaction proceeds toward equilibrium in the reverse direction?

• reactant concentrations increases

• product concentration increases

• reaction quotient consequently increases

• denominator of Q_c decreases

Multiple Choice

At equilibrium K is

• = Q

• > Q

• < Q

• 1

Multiple Choice

What law states that "At a given temperature, the reaction quotient for a system at equilibrium is constant"?

• Law of mass action

• Law of Chemical Equilibrium

• Law of Thermodynamics

• Law of Motion

Multiple Choice

What does the value of K entail?

• It provides an idea of the relative concentrations of the reactants and products in an equilibrium mixture.

• It provides an idea of the absolute concentrations of the reactants and products in an equilibrium mixture.

Multiple Choice

What does a large K at equilibrium indicate?

• very little reactant has been converted

• It indicates how rapidly or slowly equilibrium will be reached

• most of the reactant has been converted to product

• All of the above

Multiple Choice

What is the value of K when equilibrium favors the products and equilibrium lies to the right?

• >1

• <1

• 1

• 0

Multiple Choice

For the reaction

H₂(g) + Cl₂(g) ⇌ 2HCl (g)

What is the effect to equilibrium if pressure is decreased?

• increase

• decrease

• No effect

  in the number of

  moles of HCl(g)

Multiple Choice

For the reaction

H₂(g) + Cl₂(g) ⇌ 2HCl (g)

What is the equilibrium shift if pressure is decreased?

• Forward

• Backward

• No shift

Multiple Choice

For the reaction

Fe₃O₄(s) + 4H₂(g) + heat ⇌ 3Fe(s) + 4H₂O(g)

What is the effect to equilibrium if temperature is increased?

• increase

• decrease

• No effect

  in the number of

  moles

Multiple Choice

For the reaction

Fe₃O₄(s) + 4H₂(g) + heat ⇌ 3Fe(s) + 4H₂O(g)

What is the equilibrium shift if temperature is increased?

• Forward

• Backward

• No shift

Multiple Choice

For the reaction

2 NO(g) + O₂ (g) ⇌ 2NO₂(g) + heat

What is the effect to equilibrium if helium (He) is added in the reaction?

• increase

• decrease

• No effect

  in the number of

  moles

Multiple Choice

For the reaction

2 NO(g) + O₂ (g) ⇌ 2NO₂(g) + heat

What is the equilibrium shift if helium (He) is added in the reaction?

• Forward

• Backward

• No shift

Multiple Choice

For the reaction

H₂CO₃(aq) ⇌ CO₂(aq) + H₂O(l)

What is the effect to equilibrium if CO₂ is removed?

• increase

• decrease

• No effect

  in the number of

  moles

Multiple Choice

For the reaction

2 NO(g) + O₂ (g) ⇌ 2NO₂(g) + heat

What is the equilibrium shift if helium (He) is added in the reaction?

• Forward

• Backward

• No shift

Multiple Choice

For the reaction

H₂CO₃(aq) ⇌ CO₂(aq) + H₂O(l)

What is the equilibrium shift if CO₂ is removed?

• Forward

• Backward

• No shift