quiz 2

Question 1

True or false: many reactions go to completion

Answer 1

False. Many reactions stop at an intermediate state where the system contains both reactants and products

Question 2

What is chemical equilibrium

Answer 2

Concentrations of products and reactants remain constant with time

Question 3

Are reactions at chemical equilibrium static on the microscopic level

Answer 3

NO. They are dynamic microscopically and static MACROscopically

Question 4

Describe the microscopic change occurring in a reaction at equilibrium

Answer 4

Reaction continues to occur in both the forwards and reverse directions

Question 5

Do the concentrations of reactants and products change in a reaction at equilibrium

Answer 5

No

Question 6

Describe the relationship between the rate of the forward reaction and reverse reaction

Answer 6

The rate of the forward reaction and reverse reaction are equal

Question 7

Where does the equilibrium lie when a reaction goes to completion

Answer 7

To the right

Question 8

Where does the equilibrium lie when a reaction does not proceed much

Answer 8

To the left

Question 9

How does the law of mass action work

Answer 9

Gives K the equilibrium constant
Concentrations of products / reactions
Each compound is raised to the exponent of their coefficient

Question 10

When we reverse reaction what happens to K

Answer 10

K = 1/K

Question 11

When we multiply the coefficients by a number what happens to K

Answer 11

Multiply by 1/2

K = K^(1/2)

Question 12

When we add equations what happens to the Ks

Answer 12

A + B

K (of A) x K (of B) = K

Question 13

When does Kp = Kc

Answer 13

When Δn = 0

Question 14

State the formula for Kp

Answer 14

Kp = Kc (RT)^(Δn)

Question 15

What is not included in calculating the equilibrium constant

Answer 15

Solids or liquids

Question 16

What is the reaction quotient Q

Answer 16

Q is the law of mass action with INITIAL concentrations

Question 17

When Q

Answer 17

Too much reactant, so shifts to right

Question 18

When Q=K

Answer 18

At equilibrium

Question 19

When Q>K

Answer 19

Too much product, so shifts to left

Question 20

What does an ICE table stand for

Answer 20

I = initial 
C = change 
E = equilibrium

Question 21

What is the 5% rule

Answer 21

When we have x^3, cubic function, must assume x in denominator is 0 and solve. THEN must check approximation and see if under 5%

Question 22

What are the units for an ICE table

Answer 22

Moles, molarity or partial pressures

Question 23

What is le Chateliers principle

Answer 23

If a change is imposed on a system at equilibrium, the position of equilibrium will shift in a direction which minimizes the change

Question 24

According to le Chateliers principle what happens if a reactant or product is added

Answer 24

Shift to lower the concentration of it

Question 25

According to le Chateliers principle what happens if a reactant or product is removed

Answer 25

Shift to increase concentration of it

Question 26

Do solids or liquids affect le Chateliers principle

Answer 26

No

Question 27

Describe what happens if pressure increases according to le Chateliers principle

Answer 27

Volume must decrease so shift to decrease moles

**no change if moles are the same on both sides

Question 28

Describe what happens if pressure decreases according to le Chateliers principle

Answer 28

Volume must increase so shift to increase moles

Question 29

How does heat work with le Chateliers principle

Answer 29

By treating heat as a reactant or product we can predict the shift of equilibrium