Question

1.What effect would adding water (H2O) have on this reaction over time?

(NH4)2CO3(s) ⇌ 2NH3(g) +CO2(g) +H2O(g)

A.
The concentration of products would increase, and the concentration of reactants would decrease.
B.
The concentrations of both products and reactants would increase.
C.
The concentration of products would decrease, and the concentration of reactants would increase.
D.
The concentrations of both products and reactants would decrease.

2.Which statement is true of a catalyst?

A.
It behaves as a reactant in a chemical reaction.
B.
It increases the temperature of a reaction.
C.
It decreases the concentration of the products.
D.
It accelerates the reaction rates of a mixture.

3.Which statement is always true about a reversible chemical reaction?

A.
The concentration of reactants is higher than that of the products.
B.
The products can form reactants, and the reactants can form products.
C.
The concentrations of reactants and products are not constant.
D.
The concentration of the products is higher than that of the reactants.

4.Classify the outcomes based on whether they are caused by ADDING or REMOVING a reactant from a chemical reaction.

-The rate of the forward
reaction increases.

-The rate of the reverse
reaction increases.

-The concentration of
products increases.

-The concentration of
products decreases.

Answer 1

1) Water is one of the products in the given reaction. Based on Le Chatelier's principle addition of water will shift the equilibrium in a direction so as to undo the effect. Hence, the reaction will shift towards the reactant

Ans. C) Concentration of products would decrease and the reactants would increase.

2) Ans D) A catalyst accelerates the reaction rates of a mixture

3) A reversible reaction is one which can progress in the forward and reverse directions.

Ans B) The products can form reactants and the reactants can form products

4)

-The rate of forward reaction increases- ADDING REACTANT

- Rate of reverse reaction increases - REMOVING REACTANT

- Concentration of products increases- ADDING REACTANT

- Concentration of product decreases- REMOVING REACTANT

-

Answer 2

1) Answer is: C) The concentration of products would decrease, and the concentration of reactants would increase.

The rate of the reverse reaction will increase, which will cause reactants to form faster and the balance of the system to shift to the left.

According to Le Chatelier's Principle the position of equilibrium moves to counteract the change.

According to Le Chatelier's principle: if the concentration is changed, that will shift the equilibrium to the side that would reduce that change in concentration.

The equilibrium shift to the left, so more reactants will be produced.

2) Answer is: D. It accelerates the reaction rates of a mixture.

The amount of catalyst is the same at the end as at the beginning of the reaction.

A catalyst is a chemical species that is present at the beginning of a reaction and reappears at the end.

An intermediate forms during the reaction and disappears before the end.

Catalysis is the increase in the rate of a chemical reaction due to the participation of an additional substance called a catalyst.

Reactions occur faster with a catalyst because they require less activation energy.

3) Answer is: B. The products can form reactants, and the reactants can form products.

For example, balanced reversible chemical reaction: N₂ + 3H₂ ⇄ 2NH₃.

Nitrogen and hydrogen are reactants and ammonia is product of reaction. Reaction goes in both direction. Ammonia is synthesized from nitrogen and hydrogen and ammonia decomposes on nitrogen and hydrogen.

The amount of substance of reactants and products of reaction do not change when chemical reaction is in chemical equilibrium.

In a chemical reaction, chemical equilibrium is the state in which both reactants and products are present in concentrations which not change with time. Speed of direct and irreversible chemical reaction are equal.

4) Answers are:

a) The rate of forward reaction increases - adding a reactant.

The equilibrium shift to the right, so more products will be produced.

b) Rate of reverse reaction increases - removing a reactant.

The equilibrium shift to the left, so more reactants will be produced.

c) Concentration of products increases - adding a reactant.

The equilibrium shift to the right, so more products will be produced.

d) Concentration of product decreases- removing a reactant.

The equilibrium shift to the left, so more reactants will be produced.