Chemistry Topic 7

Question 1

At equilibrium the rate of the forward and reverse reactions are _____ and the concentrations are _____

Answer 1

equal; constant

Question 2

True or false: A closed system must be used in order to obtain equilibrium

Answer 2

True!

Question 3

What are the only two phases of substances that can be included in the equilibrium expression?

Answer 3

Gases and aqueous

Question 4

How do you find the K value when a whole reaction is multiplied by a number?

Answer 4

You raise K to that number

Question 5

What direction will the reaction go if Q is greater than K?

Answer 5

Reverse - The initial concentrations of the products are too high, they need to decrease to reach equilibrium, so they become the reactants

Question 6

What direction will the reaction go if Q is less than K?

Answer 6

Forward - The initial concentrations of the products are too low, they need to increase to reach equilibrium, so the reaction stays the same

Question 7

What does Q stand for?

Answer 7

Reactant quotient

Question 8

What does Le Chatelier’s Principle state?

Answer 8

When a reaction is at equilibrium and a change is made, the reaction will respond to minimize the effect of the change

Question 9

Le Chatelier’s Principle

What happens when you add more reactant?

Answer 9

The concentration of the product increases

Question 10

Le Chatelier’s Principle

What happens when you add more product?

Answer 10

The concentration of the reactant increases

Question 11

Le Chatelier’s Principle

What happens if you remove a reactant?

Answer 11

The concentration of the reactants will increase

Question 12

Le Chatelier’s Principle

What happens if you remove a product?

Answer 12

The concentration of the product increases

Question 13

Le Chatelier’s Principle

What types of reaction does pressure only affect?

Answer 13

Gaseous!

Question 14

Le Chatelier’s Principle

What happens when you increase the pressure?

(There are gases)

Answer 14

The reaction shifts from the side with more moles to less moles of gas

Question 15

Le Chatelier’s Principle

What happens when you decrease the pressure?

(There are gases)

Answer 15

The reaction will shift from less moles to more moles of gas

Question 16

What is the only thing that can affect the equilibrium constant?

Answer 16

Temperature!!!!

Question 17

Le Chatelier’s Principle

If reaction is exothermic, what happens if temp increases?

Include what happens to the K value

Answer 17

The reactant will increase and the K value will decrease

Question 18

Le Chatelier’s Principle

If reaction is exothermic, what happens if temp decreases?

Include what happens to the K value

Answer 18

The product will increase and the K value will increase

Question 19

Le Chatelier’s Principle

If reaction is endothermic, what happens if temp increases?

Include what happens to the K value

Answer 19

Product will increase and K value will increase

Question 20

Le Chatelier’s Principle

If reaction is endothermic, what happens if temp decreases?

Include what happens to the K value

Answer 20

Reactant will increase and K value will decrease

Question 21

Le Chatelier’s Principle

How does a catalyst affect the equilibrium and equilibrium constant

Answer 21

It doesn’t!

It just makes the reaction happen faster

Question 22

Can energy enter or leave a closed system at equilibrium?

Answer 22

No!

Question 23

What is the one thing you really need to pay attention to when solving with R, G, H or S?

Answer 23

Units!

Question 24

When delta G is negative, the reaction is (spontaneous / non spontaneous)

Answer 24

Spontaneous!

Question 25

When delta G is positive, the reaction is (spontaneous / non spontaneous)

Answer 25

Non spontaneous!

Question 26

What does it mean if delta G is at 0?

Answer 26

The reaction is at equilibrium

Question 27

If delta G is negative, what K value (>1 or <1) will favor the product of the reaction?

Answer 27

A K value greater than 1 (>1) will favor the product with a negative delta G

Question 28

If delta G is positive, what K value (>1 or <1) will favor the reactant of the reaction?

Answer 28

A K value less than 1 (<1) will favor the reactant with a positive delta G

Question 29

What is entropy at when the reaction is at equilibrium?

Answer 29

Its maximum

Question 30

What is the equation to solve for the delta H of a reaction

Answer 30

Delta H products - Delta H reactants = Delta H reaction | This is the same for finding the delta S

Question 31

Use collision theory to explain why increasing the temp increases the rate of a certain reaction

Answer 31

The particles collide more frequently with greater energy, allowing for more effective collisions and a faster reaction

Question 32

True or False: The rate is increased by the same amount for the forwards and reverse reaction with a catalyst

Answer 32

True!

Question 33

Define dynamic equilibrium

Answer 33

When the rates of forward and reverse reactions are equal

Question 34

True or False: When the rate of evaporation equals the rate of condensation in a particular reaction, does that mean its at equilibrium?

Answer 34

Yes! The forwards and reverse rates are equal

Question 35

When at phase equilibrium, will the amounts of liquid and gas present change?

Answer 35

No

Question 36

For a reaction, if the K increases when temp increases is it endo or exothermic? Explain

Answer 36

Endothermic because as temp increases you get more products

Question 37

How do entropy and Gibbs free energy change as a system moves towards equilibrium?

Answer 37

Gibbs free energy (delta G) approaches minimum and entropy approaches maximum.