Reversible Reactions and Equilibrium

What is produced in the backward reaction in this equilibrium, when the reaction goes from right to left: NH4Cl(s) ⇌ NH3(g) + HCl(g)?

• NH₄Cl(s)

• NH₃(g) + HCl(g)

• NH₄Cl(s) + NH₃(g) + HCl(g)

If the forward reaction is endothermic, what can be deduced about the reverse reaction?

• It is also endothermic

• There is no energy change

• It is exothermic

Tags

NGSS.HS-PS1-4

The equation for the Haber process is: N₂ + 3H₂ ⇌ 2NH₃. What gases will be present at equilibrium?

• Nitrogen and hydrogen

• Nitrogen, hydrogen and ammonia

• Ammonia only

The equilibrium between carbon dioxide gas and carbonic acid is very important in biology and environmental science. CO_2(g) + H₂O_(l) —> H₂CO3(aq)

Which one of the following is the correct equilibrium constant expression (Kc) for this reaction?

• Kc= 1/ [H₂CO₃]

• Kc= [CO₂]/ [H₂CO₃]

• Kc= [H₂CO₃] / [CO₂]

• Kc= [CO₂] [H₂O] / [H₂CO₃]

• Kc= [H₂CO₃] / [CO₂] [H₂O]

Tags

NGSS.HS-PS1-2

NGSS.HS-PS1-7

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.

This symbol indicates that a reaction is _____

• reversible

• irreversible

Tags

NGSS.HS-PS1-6

Which of the two graphs reaches equilibrium?

• Neither

• The left

• Both

• The right

Tags

NGSS.HS-PS1-4

Which of the following is NOT true at equilibrium?

• The concentrations of reactants and products do not change.

• The forward and reverse reactions proceed at the same rate.

• The concentration of the reactants is equal to the concentration of the products.

• The forward and reverse reactions continue to occur.

Tags

NGSS.HS-PS1-6

Select all of the statements that are always correct about dynamic equilibrium

• established when the product and reactant concentrations are equal

• achieved when the forward and reverse reaction rates are same

• established when the concentration of reactants is unchanging

• achieved when the concentration ratio of reactants to products becomes stable

• achieved when the forward and reverse reactions stop occurring

Given the equation representing a reaction:

N₂O_4(g) ⇌ 2NO_2(g)

Which statement describes this reaction at equilibrium?

• The concentration of N₂O₄(g) must equal the concentration of NO₂(g).

• The concentration of N₂O₄(g) and the concentration of NO₂(g) must be constant.

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

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