C19 Equilibrium Flashcards
What does it mean when a reaction is at equilibrium
The rate of forward and reverse reactions are equal
What are the methods that can be used to measure equilibrium
Measure change in colour/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
What does mole fraction mean
The amount of a given component in a given reaction mixture
Write the equation used to calculate mole fraction
Mole fraction = number of moles of substance A / total number of moles of all substances
What’s does partial pressure mean
The pressure exerted by a single species in a reaction vessel
What’s the symbol for partial pressure
P
Write the equation used to calculate partial pressure
Partial pressure = mole fraction x total pressure
What’s the relationship between conc of a substance and its partial pressure
Conc of a substance is proportional to its partial pressure
What’s are the 3 common units of pressure used in chemistry
Pascals
Atmospheres
Newtons per square metre
What type of brackets are used in Kc expressions
Square brackets
What type of brackets are used in Kip expressions
Round brackets
How do you calculate the units for Kip
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
What’s the symbol of equilibrium constant
K
What does it mean when K is greater than 1
Reaction favours product
What does it mean when K is lesser than 1
The reaction favours reactants
What’s the effect of increasing temperature on K
Equilibrium shifts to the direction of endothermic reaction
What’s the effect of decreasing temperature on K
Equilibrium shifts to the direction of exothermic reaction
What is the only factor that affects K
Temperature
What the effect of increasing temperature on K for a forward endothermic reaction
K increases as temperature increases
What’s the effect of increasing temperature on K for a forward exothermic reaction
K decreases as temperature increases
What effect does catalyst have on K
Catalysts do not affect the position of equilibrium, they only have an effect on the rate of reaction
