Chemical equilibriums

Question 1

What are the three charateristics of a chemical equilibrium?

Answer 1

1-Rates of the forward and reverse reactions are equal
2- macroscopic properties are constant
3-these reactions cans tart from either the reactants or the products

Question 2

What is enthalpy?

Answer 2

The heat energy of the system

Question 3

Chemical systems tend towards maximum or minimum enthalpy?

Answer 3

Minimum enthalpy.

they tend to go exothermic.

Question 4

When saying that chemical systems tend towards minimum enthalpy, what does this really mean?

Answer 4

Chemical systems tend to go exothermic.

Question 5

What is entropy?

Answer 5

Randomness or chaos of the system

Question 6

Do chemical systems tend towards maximum or minimum entropy?

Answer 6

Maximum entropy.

Question 7

Lists all four states in order from greatest to least in terms of entropy

Answer 7

Gas, aq, liquids, solids

Question 8

What happens when enthalpy and entropy both tend towards the product?

Answer 8

The reaction will start spontaneously and likely go to completion

Question 9

When a reaction starts spontaneously and goes to completion, where are entropy and enthalpy tending towards?

Answer 9

They both tend towards products

Question 10

What happends when both enthalpy and entropy tend towards the reactsnts?

Answer 10

The reaction will not start

Question 11

Where are enthalpy and entropy tending towards if the reaction will not start if unaided?

Answer 11

They are both tending towards the reactants

Question 12

What happens when entropy and enthalpy are in opposition?

Answer 12

The reaction will start spontaneously and go to equilibrium.

Question 13

What is le chateliers principal

Answer 13

“a system in eqilibruim will react to a stress in such a way as to counteract that stress and form a new equilibrium state.”

Question 14

What happens to an equilibrium when the temperature is increased?

Answer 14

The equilibrium will shift towards endothermic

Question 15

When an equilibrium shifts towards endothermic due to a temperature change, was the temp increased or decreased?

Answer 15

Increased

Question 16

What happens to and equilibrium when the temperature is decreased?

Answer 16

The equilibrium shifts to exothermic

Question 17

When an equilibrium shifts to exothermic due to a temperature change, was the temperature increased or decreased?

Answer 17

Decreased

Question 18

When the concentration of the reactants are increased, which was does the equilibrium shift?

Answer 18

To the products

Question 19

When the concentration of the products are increased, which way does the equilibrium shift?

Answer 19

To the reactants

Question 20

When the concentration of the reactsnts are decreased, which way does the equilibrium shift?

Answer 20

To the reactants

Question 21

When the concentration of the products are decreased, which way does the equilibrium shift?

Answer 21

to the products

Question 22

When a catalyst is added to a system, which way does the equilibrium shift?

Answer 22

There is no shift

Question 23

When the volume is increased, which way does the equilibrium shift?

Answer 23

It shifts to the side with the most number of gas particles.

Question 24

When the pressure is decreased, which way does the equilibrium shift?

Answer 24

It shifts to the side with the most number of gas particles

Question 25

When the volume is decreased, which way does the equilibrium shift?

Answer 25

It shifts to the side with the lowest number of gas particles

Question 26

When the pressure is increased, which way does the equilibrium shift?

Answer 26

It shifts to the side with the lowest number of gas particles.

Question 27

What are the two characteristics of the constant of equilibrium?

Answer 27

• describes the position of the equilibrium

- only a change in temperature will change the value of the constant

Question 28

How do you calculate the constant of equilibrium?

Answer 28

[products][products] / [reactants] [reactants]

Question 29

What states are included when calculating the constant of equilibrium

Answer 29

Gasses are only included.

Liquids are included if there are two or more liquids in the system.

Question 30

What is a dynamic equilibrium

Answer 30

An equilibrium situation in which there are microscopic changes, but no macroscopic changes.

Question 31

What is a spontaneous change

Answer 31

a change that happens by itself

Question 32

What are the two tendancies that exist in any reaction

Answer 32

• the tendancy for a reaction to go to the side with maximum randomness (maximum entropy)
• The tendency for a reaction to go to the side with minimum energy (exothermic, minimum enthalpy)

Question 33

describe the tendancy for a reaction to go to the side with minimum enthalpy

Answer 33

the tendency to go to the side with minimum enthalpy is a tendency to go to the “downhill” side in a reaction

• in an exothermic reaction, the product side is favoured
• in an endothermic reaction, the reactant side is favoured

Question 34

In an exothermic reaction, which side is favoured in terms of minimum enthalpy

Answer 34

the product side is favoured

Question 35

In an endothermic reaction, which side is favoured in terms of minimum enthalpy

Answer 35

The reactant side is favoured

Question 36

describe the tendency for a reaction to go to the side with maximum entropy

Answer 36

the side of a reaction containing the most particles of the most random phase is favoured

Question 37

When is trial keq used

Answer 37

when you are not sure that the equilibrium is at equilibrium

Question 38

which way does the reaction shift if the trial keq is less than the actual keq?

Answer 38

to the products

Question 39

Which way does the reaction shift if the trial keq is greater than the actual keq?

Answer 39

to the reactants