AP Chemistry Equilibrium

The equilibrium constant expression for the reaction BrF_5(g) —> Br_2(g) + F_2(g) is

• Kc = [Br₂] [F₂] / [BrF_5]

• Kc = [BrF₅]² / [Br₂][F₂]⁵

• Kc = [Br₂] [F₂]⁵ / [BrF₅]²

• Kc = 2[BrF₅]² / ([Br₂] × 5[F₂]⁵)

• Kc = [Br₂] [F₂]² / [BrF₅]⁵

Tags

NGSS.HS-PS1-7

Calculate Kc for the reaction HI_(g) —> H_2(g) + I_2(g) given that the concentrations of each species at equilibrium are as follows: [HI] = 0.85 mol/L, [I₂] = 0.60 mol/L, [H₂] = 0.27mol/L.

• 0.19

• 0.22

• 4.5

• 5.25

• 160

A chemical reaction in which products can react to re-form reactants is known as a(n)

• reforming reaction

• reversible reaction.

• buffered reaction

• stoichiometric reaction.

For any reaction at chemical equilibrium, the concentrations of products and reactants

• are equal.

• change

• remain unchanged

• decrease

Tags

NGSS.HS-PS1-6

When the forward and reverse reactions are occurring at the same rate, the reaction is said to be at:

• Chemical equilibrium

• Chemical reaction

• Chemical constant

• Chemical peace

Tags

NGSS.HS-PS1-6

A very high value for K indicates that

• reactants are favored.

• products are favored.

• equilibrium is reached slowly.

• equilibrium has been reached

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

Tags

NGSS.HS-PS1-6

An exothermic reaction is allowed to reach equilibrium. If heat energy is then removed, the equilibrium will shift

• toward the middle

• toward the reactant side

• toward the product side

Tags

NGSS.HS-PS1-4

TRUE or FALSE:

"At equilibrium, the RATES of the forward and reverse reactions are EQUAL"

• True

• False

Tags

NGSS.HS-PS1-7

Why is equilibrium called a dynamic state?

• Chemists try to convert as much reactants as possible into products.

• The reactions at equilibrium continue to take place once equilibrium is established.

• The products of a forward reaction are favored, so equilibrium lies to the right.

• All chemical reactions are considered to be reversible under suitable conditions.