Chemical Reactions & Equilibrium

Question 1

Describe the criteria for a successful collision

Answer 1

-reactant molecules must collide with each other
-reactant molecule must collide with sufficient energy to break the bonds within the reactants
-reactant molecules must collide with the correct orientation to break the bonds within the reactants

Question 2

define rate of reaction

Answer 2

the change in concentration of the reactants or products per unit time

Question 3

How does increased surface area influence rate of reaction

Answer 3

increase surfaced area
increased frequency of successful collisions per unit time
increased rate of reaction

Question 4

How does increased concentration influence rate of reaction

Answer 4

increase concentration
increase number of particles in a given volume
increase frequency of successful collisions per unit time
increased rate of reaction

Question 5

how do you increase pressure

Answer 5

decrease the volume of the system

Question 6

how do you decrease pressure

Answer 6

increase the volume of the system

Question 7

How does increased pressure inference rate of reaction

Answer 7

increase pressure
increase concentration of particles
increase frequency of successful collisions per unit time
increased rate of reaction

Question 8

How does increased temperature influence rate of reaction

Answer 8

increase temperature
increased average kinetic energy
increased proportion of particles with energy greater than or equal to the activation energy
increased frequency of successful collisions per unit time
increased rate of reaction

Question 9

Two types of catalysts

Answer 9

homogenous and heterogenous

Question 10

How do catalysts increase rate of ration

Answer 10

provide an alternative reaction pathway by lowering activation energy and in turn increasing the proportion of particles with energy equal to or above the activation energy.

increasing the frequency of successful collisions per unit time and increasing rate of reaction

Question 11

define equilibrium

Answer 11

when the forward and back reactions occur at the same rate, the reaction is said to be at equilibrium

Question 12

Identify conditions at equilibrium

Answer 12

-amount of mol of substance is constant
-concentration of substances is constant
-pressure constant (gas system)
-temperature constant

Question 13

purpose of Kc value

Answer 13

it shows the extent of the reaction

Question 14

how to calculate Kc value

Answer 14

concentration of product(s) to power of coefficient / concentration of reactant(s) to power of coefficients

Question 15

what impacts Kc

Answer 15

temperature ONLY

Question 16

How to get units of Kc

Answer 16

coefficients of product / coefficients of reactant (simplify)

Question 17

If Kc is greater than 10^4 then

Answer 17

reaction goes to completion (negligible amount of reactant left)

Question 18

If Kc is less than 10^-4 then

Answer 18

reaction occurs to a negligible extent (negligible amount of product formed)

Question 19

Kc values between 10^-4 and 10^4 are

Answer 19

indicative of the forward and back reactions occurring to a moderate extent

Question 20

Find K2 for the reverse reaction of K

Answer 20

1/K

Question 21

Find K2 for the coefficients of reaction K being doubled

Answer 21

K^2

Question 22

Find K2 for the coefficients of reaction K being halved

Answer 22

K^1/2

Question 23

How is Kc influenced in EXOTHERMIC reaction

Answer 23

increase in temperature decreases K
decrease in temperature increases K

Question 24

How is Kc influenced in ENDOTHERMIC reaction

Answer 24

increase in temperature increase K
decrease in temperature decreases K

Question 25

What is Q (reaction coefficient)

Answer 25

same calculation as K but not necessarily at equilibrium

Question 26

How are Q and Kc related to equilibrium

Answer 26

if KcQ then the system will shift right to achieve equilibrium and more products will form if Kc = Q then the system is at equilibrium

Question 27

ICEFC stands for

Answer 27

initial mol change in mol number of mol at equilibrium Final CONCENTRATION

Question 28

Key principal of Le Chatelier's

Answer 28

if an equilibrium system is subjected to change then the system will shift in a direction that PARTIALLY OPPOSES that change

Question 29

How does temperature influence equilibrium yield

Answer 29

An increase in temperature will be partially opposed by favouring the energy absorbing endothermic reaction A decrease in temperature will be partially opposed by favouring the energy releasing exothermic reaction

Question 30

How do catalysts influence equilibrium yield

Answer 30

NO change as they effect the rate of the forwards and reverse reactions to an equal extent

Question 31

How does the addition of an inert gas influence equilibrium yield

Answer 31

has no effect on the position of equilibrium, provided the volume of the container remains constant

Question 32

Name 3 inert gases

Answer 32

He Ne Ar

Question 33

How does the addition of a reactant or product influence equilibrium

Answer 33

addition of a product or reactant increases the concentration of that reactant or product and hence the reaction that uses up that reactant or product will be promoted to partially opposes the increase in concentration of the reactant or product and hence decrease the concentration of that reactant or product

Question 34

How does removal of a reactant or product influence equilibrium

Answer 34

removal of a product or reactant decreases the concentration of that reactant or product and hence the reaction that produces that reactant or product will be promoted to partially opposes the decreases in concentration of the reactant or product and hence increase the concentration of that reactant or product

Question 35

How does dilution impact equilibrium

Answer 35

a dilution decreases the concentration of all the reactants and products and is partially opposed by favouring the reaction that produces more mol of solution

Question 36

How does volume influence pressure

Answer 36

increase volume decreases pressure & decrease volume increases pressure

Question 37

How does pressure impact equilibrium

Answer 37

increase in pressure is partially opposed by promoting the reaction that produces fewer mole of gas decrease in pressure is aerially opposed by favouring the reaction that produces more mole of gas

Question 38

Write the two chemical reactions for CO poisoning

Answer 38

Hb4 + 4O2 --> Hb4O8. -K1 Hb4 + 4CO --> Hb4(CO)4. -K2

Question 39

Why is CO poisoning dangerous

Answer 39

Because K2 is much greater than K1 then even at very low concentrations haemoglobin in the blood and CO bind to form the complex - Hb4(CO)4

Question 40

Why would high concentrations of oxygen be delivered for CO poisoning

Answer 40

By pumping in oxygen, this increases the oxygen concentration and favours the forward reaction to produce Hb4O8. This reduces the amount of Hb4 in the blood and as a result the second reaction will shift left to partially opposes the decrease in Hb4 concentration and produce more Hb4. Less Hb(CO)4 complexes form and CO poisoning is minimised

Question 41

why does addition of inert gas have have no effect on ror

Answer 41

inert gas particles are not apart of the reaction and hence do not affect the number of collisions and successful collisions per unit time.