Physical and Chemical Equilibrium

Chapter 6 : Chemical Equilibrium

Multiple Choice

What is a Reversible reaction

• A reaction going forward and backward at same time

• A reaction going forward and backward at different time

• forward reaction

• backward reaction

Multiple Choice

What is the symbol which is used in reversible reactions?

• →

• Δ

• +

• ⇌

Multiple Choice

When the rate of the forward reaction is equal to the rate of backward reaction, the system is said to be in

• Chemical Equilibrium
• Chemical Balance
• Chemical Constant
• Chemical Reaction

Multiple Choice

What are the two factors to look for when determining if the reaction is at equilibrium?

• Forward reaction rate is faster than the reverse and concentrations are equal
• Forward and reverse reaction rates are equal and concentration is constant
• Forward and revers reaction rates are equal and concentration is equal
• Forward reaction rate is faster than the reverse and concentration is equal

Multiple Choice

Which of the following is NOT true at equilibrium?

• The forward and reverse reactions proceed at the same rate.
• The concentrations of reactants and products do not change.
• The concentration of the reactants is equal to the concentration of the products.
• The forward and reverse reactions continue to occur.

Multiple Choice

A chemical equilibrium may be established by starting a reaction with ____________

• reactants only

• products only

• equal quantities of reactants and products

• any quantities of reactants and products

• all of the above

Multiple Choice

Which is the reactant - and why?

• A, as concentration decreases
• B, as concentration decreases
• A, as concentration increases
• B, as concentration increases

Multiple Choice

At what time the reaction reached equilibrium?

• t₁
• t₂
• t₃
• t₄

Multiple Choice

What are [A] and [B]?

• concentration of reactants
• concentration of products
• energy of reactants
• energy of products

Multiple Choice

What is the K_c expression for this reaction?
   2 NO_(g)  +  O_2(g) ⇌  2 NO_2(g)

• K_c = [NO₂]² / [NO]² [O₂]
• K_c =  [NO]² [O₂] / [NO₂]²
• K_c = [NO]² [O₂] [NO₂]²
• K_c = [NO₂]² / [NO]² +  [O₂]

Multiple Choice

What is the equilibrium-constant expression for

CO₂(g) + H₂(g) ⇌ CO(g) + H₂O(l)

• K_c= [CO][H₂O] / [CO₂][H₂]

• K_c= [CO₂][H₂] / [CO]

• K_c= [CO₂][H₂] / [CO][H₂O]

• K_c= [CO] / [CO₂][H₂]

Multiple Choice

If the equilibrium constant is much less than one (K << 1) then

• Equilibrium is not established.
• Equilibrium lies to the right (products are favored)
• Equilibrium lies to the left (reactants are favored)
• Neither products or reactants are favored.

Multiple Choice

If the equilibrium constant is much greater than one (K >> 1) then

• Equilibrium is not established.
• Equilibrium lies to the right (products are favored)
• Equilibrium lies to the left (reactants are favored)
• Neither products or reactants are favored.

Multiple Choice

If the reaction quotient Q has a value larger than the related equilibrium constant, K _________

• the reaction is at equilibrium

• the reaction is not at equilibrium, and will make more products at the expense of reactants

• the reaction is not at equilibrium, and will make more reactants at the expense of products

• the value of K will increase until it is equal to Q

Multiple Choice

If the reaction quotient Q has a smaller value than the related equilibrium constant, K, _________

• the reaction is at equilibrium

• the reaction is not at equilibrium, and will make more products at the expense of the reactants

• the reaction is not at equilibrium, and will make more reactants at the expense of the products

• the value of K will not increase until it is equal to Q