5.1.2: How far?

Question 1

What does it mean when a reaction is at equilibrium?

Answer 1

The rate of forward and reverse reactions are equal

Question 2

What are the methods that can be used to measure equilibrium?

Answer 2

● Measure change in colour or colour intensity using colorimeter
● Use pH probe
● Measure electrical conductivity
● Titration - used when equilibrium is slow so that titration can be completed before there is much change in equilibrium mixture

Question 3

What does mole fraction mean?

Answer 3

The amount of a given component in a given reaction mixture

Question 4

Write the equation used to calculate mole fraction

Answer 4

Mole fraction = number of moles of

substance A / total number of moles of all substances

Question 5

What does partial pressure mean?

Answer 5

The pressure exerted by a single species

in a reaction vessel

Question 6

What is the symbol for partial pressure?

Answer 6

P

Question 7

Write the equation used to calculate partial pressure

Answer 7

Partial pressure = mole fraction x total pressure

Question 8

What is the relationship between concentration of a substance and its partial pressure?

Answer 8

Concentration of a substance is proportional to its partial pressure

Question 9

What are the 3 common units of pressure used in chemistry?

Answer 9

● Pascals
● Atmospheres
● Newtons per square metre

Question 10

What type of brackets are used in Kc expressions?

Answer 10

Square brackets

Question 11

What type of brackets are used in Kp expressions?

Answer 11

Round brackets

Question 12

How do you calculate the units for Kp?

Answer 12

Write out the units for the partial pressures in the
same arrangement as the Kp equation and cancel
out/multiply together.
Usually in Pa, kPa, atm etc. DO NOT CHANGE
UNITS

Question 13

What is the symbol of equilibrium constant?

Answer 13

K

Question 14

What does it mean when K is greater than 1?

Answer 14

● Reaction favours product

Question 15

What does it mean when K is lesser than 1?

Answer 15

The reaction favours reactants

Question 16

What is the effect of increasing temperature on K?

Answer 16

Equilibrium shifts to the direction of endothermic reaction

Question 17

What is the effect of decreasing temperature on K?

Answer 17

Equilibrium shifts to the direction of

exothermic reaction

Question 18

What is the only factor that affects K?

Answer 18

Temperature

Question 19

What is the effect of increasing temperature on K for a forward endothermic reaction?

Answer 19

K increases as temperature increases

Question 20

What is the effect of increasing temperature on K for a forward exothermic reaction?

Answer 20

K decreases as temperature increases

Question 21

What effect does catalyst have on K ?

Answer 21

Catalysts does not affect the position of
equilibrium, they only have an effect on
the rate of reaction