Chemical Equilibrium 13.1-13.3 Timberlake

Chemical Equilibrium 13.1-13.3 Timberlake

By Nicole Woltschlaeger

Multiple Choice

Which of the following will increase the rate of a reaction?

• removal of a catalyst

• a decrease in temperature

• a decrease in the concentration of reactants

• addition of a catalyst

Multiple Choice

According to the collision theory, what are two of the conditions that are needed for a reaction to occur?

• correct orientation and a low temperature

• collision energy equal to the activation energy and the correct orientation

• collision energy less than the activation energy and the correct orientation

• a catalyst and a high temperature

Results in more collisions with adequate activation energy.

More collisions.

​

Decreases activation energy.​

Reason

Increase Temperature

​

Increase reactant concentration.

​

Addition of a catalyst.​

Factor

Factors that increase reaction rate

Timberlake 13.1

Multiple Choice

For every 10^oC increase in temperature, most reaction rates approximately

• double

• triple

• halve

• quadruple

Multiple Choice

How would adding some NO change the rate of reaction?

• The rate would increase.

• The rate would decrease.

• The rate would stay the same.

Multiple Choice

How would decreasing the temperature change the rate of reaction?

• The rate would increase.

• The rate would decrease.

• The rate would stay the same.

Multiple Choice

How would removing some H₂ change the rate of reaction?

• The rate would increase.

• The rate would decrease.

• The rate would stay the same.

Multiple Choice

How would adding a catalyst change the rate of reaction?

• The rate would increase.

• The rate would decrease.

• The rate would stay the same.

Reversible Reactions

There are two reaction rates

• One of the forward reaction

• One of the reverse reaction

​When molecules begin to react, the forward reaction is faster.

As the reaction proceeds, the forward rate decreases, and the reverse rate increases.​

Timberlake 13.2

Equilibrium

​Equilibrium

Eventually the forward and reverse rates are equal, at which point the reaction is at equilibrium.

​

At this point, the concentration of reactants and products ​remains constant

Timberlake 13.2

Equilibrium

Multiple Choice

Before equilibrium is reached, the concentration of reactants and products____________.

• equal

• not equal

• change

• do not change

Multiple Choice

Initially, reactants placed in a container have a ___________rate of reaction than the rate of reaction of the products.

• equal

• not equal

• slower

• faster

Multiple Choice

At equilibrium, the rate of reaction of the forward reaction is __________ to the rate of reaction of the reverse reaction.

• equal

• not equal

Multiple Choice

Which of the following are at equilibrium?

• The rate of the forward reaction is twice as fast as the rate of the reverse reaction.

• The concentration of the reactants and products do not change.

• The rate of the reverse reaction does not change.

​Equilibrium Expression, Kc

​Consider the following reaction:

​

​

The equilibrium expression is defined as:​

​

​

​

When the concentrations of the reactants and p​roducts are plugged into the expression at equilibrium, the calculated value is the equilibrium constant.

​

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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]

Solids and liquids...

The concentrations of pure solids and pure liquids do not change, they are constant...​

...thus, do not include solids and liquids in equilibrium expressions.

Some text here about the topic of discussion

Multiple Choice

What is the equilibrium expression for:
Fe₃O₄(s) + 4H₂(g) <=> 3Fe(s) + 4H₂O(g)
K_c =

• [Fe]³ [H₂O]⁴  / [Fe₃O₄] [H₂]⁴
• [Fe₃O₄] [H₂]⁴ /  [Fe]³ [H₂O]⁴
• [H₂O]⁴ / [H₂]⁴
• [Fe] [H₂O] / [Fe₃O₄] [H₂]