Unit 5

Question 1

What is an equilibrium?

Answer 1

A dynamic condition in which the forward rate of a process equals the reverse rate in a closed system

Question 2

What is equilibrium shown by? What does this mean?

Answer 2

It is shown by a double headed arrow

It means the process occurs in both directions

Question 3

What does it mean if the forward reaction is favoured in an equilibrium reaction?

Answer 3

It means the forward reaction is nearly complete before the reverse reaction establishes equilibrium
Higher concentration of products than reactants at equilibrium

Question 4

What does it mean if the reverse reaction is favoured in an equilibrium reaction?

Answer 4

It means the forward reaction is just starting when the reverse reaction establishes equilibrium.
There is a higher concentration of reactants than products at equilibrium

Question 5

How do we analyze a graph of equilibrium reactants and products to see which is favoured?

Answer 5

Products start at zero and go up while reactants start at a higher number and go down.
Which ever line is higher than the other is where the reaction is favoured

Question 6

What is Le Châtelier’s principle?

Answer 6

States that when an equilibrium is stressed, it will shift to relieve the stress since they are dynamic

Question 7

How do you calculate the movement of a reaction when the pressure is increased?

Answer 7

Count the number of mols of gas on each side, then the equation will shift to whichever side has less mols of gas

Question 8

If pressure is increased or decreased, and the number of mols of gas are the same on both sides where does the equation shift?

Answer 8

No change.

Question 9

Which states of elements don’t affect an equilibrium?

Answer 9

Liquids (l) or solids (s)

Question 10

What is an endothermic reaction?

Answer 10

Where the energy (heat) is on the reactant side (left side)

Question 11

What is an exothermic reaction?

Answer 11

Where the energy (heat) is on the product side (right)

Question 12

What is the Keq equation?

Answer 12

Keq= products/reactants
Coefficients of compounds are used as exponents
Ex: aA + bB >< cC + dD
Keq= (C^c)(D^d) / (A^a)(B^b)

Question 13

What states of elements are not included in the Keq?

Answer 13

Liquids (l) and solids (s)

Question 14

If Keq is greater than one (>1) what is favoured?

Answer 14

Products are favoured (more products around at equilibrium)

Question 15

If Keq is less than 1 (<1) what is favoured?

Answer 15

Reactants are favoured (more reactants around at equilibrium)

Question 16

If Keq is equal to one (=1) what is favoured?

Answer 16

None. Reactants and products are equal concentration at equilibrium

Question 17

Does changing the pressure, concentration, or adding a catalyst affect the Keq?

Answer 17

No

Question 18

For an endothermic reaction, how does the temperature affect the Keq?

Answer 18

When the temperature goes up, the Keq goes up
When the temperature goes down, the Keq goes down

Parallel

Question 19

For an exothermic reaction, how does the temperature affect the Keq?

Answer 19

When the temperature goes up, the Keq goes down
When the temperature goes down, the Keq goes up

Inverse

Question 20

When reactants are converted into products, their concentrations ___________ and the concentrations of the products ___________

Answer 20

Decrease

Increase

Question 21

What would a homogenous reaction mean?

Answer 21

All gases or all aqueous, etc

Question 22

What would a heterozygous reaction mean?

Answer 22

Some gas some aqueous, etc

Question 23

Reactions tend to run to completion if a product is ________

Answer 23

Is precipitated as a solid