10-11. Equilibrium I and II

Question 1

what is a reversible reaction

Answer 1

a reaction that goes both ways

Question 2

what is dynamic equilibrium

Answer 2

when the rate of the forwards reaction is the same as the rate of the backwards reaction

Question 3

what remains constant at dynamic equilibrium

Answer 3

concentrations of reactants and products

Question 4

what type of system does dynamic equilibrium occur in

Answer 4

closed system

Question 5

what is a homogenous system

Answer 5

all reactants and products are in the same physical state

Question 6

what is Kc

Answer 6

the equilibrium constant involving concentrations

Question 7

aA + bB = dD + eE

Answer 7

Kc = [D]^d [E]^e / [A]^a [B]^b

Question 8

what is a heterogenous system

Answer 8

not all reactants and products are in the same physical state

Question 9

what state is included in Kc and why

Answer 9

only gases as their concentrations remain constant

Question 10

are catalysts included

Answer 10

catalysts are not included as they are not used up, they only speed up the rate at which dynamic equilibrium is reached

Question 11

what is le Chatelier’s principle

Answer 11

if there is a change in concentration, pressure or temperature, the equilibrium will shift to counteract the change

Question 12

what happens when you change concentration, pressure of temperature of a reversible reaction

Answer 12

you alter the position of equilibrium and end up with different amounts of reactants and products at equilibrium

Question 13

what do you get when the position of equilibrium moves left

Answer 13

more reactants

Question 14

what do you get when the position of equilibrium moves right

Answer 14

more products

Question 15

le chatelier’s principle for increasing concentration of reactants

Answer 15

makes more product - equilibrium shifts right

Question 16

le chatelier’s principle for increasing concentration of product

Answer 16

makes more reactants - equilibrium shifts left

Question 17

le chatelier’s principle for decreasing concentration of reactants

Answer 17

makes more reactants - equilibrium shifts left

Question 18

le chatelier’s principle for decreasing concentration of products

Answer 18

makes more products - equilibrium shifts right

Question 19

le chatelier’s principle for increasing pressure

Answer 19

equilibrium shifts to the side with fewer gas molecules
(look at number of moles on each side)

Question 20

le chatelier’s principle for decreasing pressure

Answer 20

equilibrium shifts to side with more gas molecules ( look at number of moles on each side)

Question 21

le chatelier’s principle for increasing temperature

Answer 21

equilibrium shirts to the endothermic direction to absorb the heat

Question 22

le chatelier’s principle for decreasing temperature

Answer 22

equilibrium shifts to the exothermic direction to replace the heat

Question 23

if a forward reaction is endothermic what is the reverse reaction

Answer 23

exothermic

Question 24

how to find the equilibrium constant from experimental data

Answer 24

Fe2+ + Ag+ -><- Fe3+ + Ag
1. leave iron sulfate solution and silver nitrate solution in stoppered flask at 298k, reaction will reach equilibrium
2. take samples and titrate them to work out c of Fe2+ ions
3. from this work our equilibrium concentrations of other components and then work out Kc

Question 25

what is partial pressure

Answer 25

the individual pressure of each gas in a mixture

Question 26

what is total pressure

Answer 26

the sum of all the partial pressures of individual gases in a mixture

Question 27

equation for mole fraction

Answer 27

mole fraction = number of moles of gas / total moles of a gas in a mixture

Question 28

partial pressure equation

Answer 28

partial pressure = mole fraction of gas / total pressure

Question 29

what is Kp

Answer 29

equilibrium constant involving pressure

Question 30

Kp equation

Answer 30

p(D)^d p(E)^e / p(A)^a p(B)^b

Question 31

the greater value of Kc or Kp …..

Answer 31

the further right the equilibrium lies

Question 32

the smaller value of Kc or Kp……

Answer 32

the further left the equilibrium lies

Question 33

why do Kc or Kp not change

Answer 33

as the reaction shifts to keep the equilibrium constants constant