Organic and Physical Chemistry
JUNE 2025 Mark Scheme
Activation energy - __100% correct answer as The minimum
amount of kinetic energy particles need to react.
How does separation of organic product work? - __100%
correct answer as -organic layer and aqueous layer containing
soluble impurities separate out
-open tap and run off each layer into separate beakers
What is solvent extraction? - __100% correct answer as -used if
your product and impurities are dissolved in a solution together
-shake impure product with immiscible solvent
What drying agent can be used to remove traces of water? -
__100% correct answer as anhydrous MgSO4 or CaCl2
,What method of purification should be used if there's liquids
with different boiling points? - __100% correct answer as
redistillation
How to perform distillation? - __100% correct answer as Heat
impure product and when the liquid you want boils collect in a
beaker
What method of purification should be used if product is a
solid? - __100% correct answer as Recrystallisation
What are the steps for recrystallisation? - __100% correct
answer as dissolve in minimum amount of hot solvent
leave to cool and crystals form
filter under reduced pressure using a buchner filter
Diagram of buchner filter - __100% correct answer as
Steps to test purity of organic compound? - __100% correct
answer as -pack small sample into capillary tube
-increase temperature until solid turns to a liquid
,-measure melting point and compare with data tables
How to produce cyclohexene? - __100% correct answer as 1.
-add H2SO4 and H3PO4 to a round bottom flask with
cyclohexanol
-add anti bumping granules
-heat mixture to 83'c
-collect the liquid product
2.
-transfer to separating funnel and add water
-settle in layers and filter off
3.
-drain off impure cyclohexene
-add anhydrous CaCl2 and allow mixture to dry for 20 mins
-distill again
Shaking alkenes with bromine water - __100% correct answer
as brown to colourless
, What does collision theory depend on? - __100% correct
answer as -particles must collide the right way and with the
activation energy
Draw and label a Maxwell boltzmann curve - __100% correct
answer as
What does the peak on a maxwell boltzmann curve represent? -
__100% correct answer as most likely energy of a single
molecule
What does the point slightly to the right of peak represent? -
__100% correct answer as the mean/average energy of all the
molecules
What does the area under a maxwell boltzmann curve
represent? - __100% correct answer as total number of
molecules