Equilibrium and Spontaneous Reactions

When a reversible reaction is at equilibrium, the concentration of products and the concentration of reactants must be

• decreasing

• increasing

• constant

• equal

What occurs when a reaction reaches equilibrium?

• The concentration of the reactants increases.

• The concentration of the products increases.

• The rate of the forward reaction is equal to the rate of the reverse reaction.

• The rate of the forward reaction is slower than the rate of the reverse reaction.

Which changes can reach dynamic equilibrium?

• nuclear changes, only

• chemical changes, only

• nuclear and physical changes

• chemical and physical changes

Given the equation representing a closed system:

N₂O₄(g) <--> 2NO₂(g)

Which statement describes this system at equilibrium?

• The volume of the NO2(g) is greater than the volume of the N2O4(g).

• The volume of the NO2(g) is less than the volume of the N2O4(g).

• The rate of the forward reaction and the rate of the reverse reaction are equal.

• The rate of the forward reaction and the rate of the reverse reaction are unequal.

Which statement must be true when solution equilibrium occurs?

• The solution is at STP.

• The solution is supersaturated.

• The concentration of the solution remains constant.

• The masses of the dissolved solute and the undissolved solute are equal.

Given the equation representing a system at equilibrium:

When the concentration of Cl^– (aq) is increased, the concentration of Ag⁺ (aq)

• decreases, and the amount of AgCl(s) increases

• decreases, and the amount of AgCl(s) decreases

• increases, and the amount of AgCl(s) increases

• increases, and the amount of AgCl(s) decreases

A solution that is at equilibrium must be

• concentrated

• dilute

• saturated

• unsaturated

iven the equation representing a phase change at equilibrium:

H₂O(s) <--> H₂O(l)

Which statement describes this equilibrium?

• The H₂O(s) melts faster than the H₂O(l) freezes.

• The H₂O(l) freezes faster than the H₂O(s) melts.

• The mass of H₂O(s) must equal the mass of H₂O(l).

• The mass of H₂O(l) and the mass of H₂O(s) each remain constant.

Given the equation representing a system at equilibrium:

H₂O (s) <--> H₂0 (l)

At which temperature does this equilibrium exist at 101.3 kilopascals?

• 0 K

• 0°C

• 32 K

• 273°C

A liquid in a stoppered flask is allowed to stand at constant temperature until the liquid level in the flask remains constant. Which condition then exists in the flask?

• Only liquid is evaporating.

• Only vapor is condensing.

• The rate of condensation is greater than the rate of evaporation.

• The rate of condensation is equal to the rate of evaporation.