AQA CHEMISTRY PAPER 2 EXAM
Calculate rate of reaction
change in quantity/time
How to increase rate of reaction
increase surface area/concentration/pressure
increase temperature
catalyst, reduce activation energy
Reversible reaction
a chemical reaction in which the products re-form the original reactants
Le Chatelier's Principle
States that if a stress is applied to a system at equilibrium, the system shifts in the
direction that relieves the stress.
Increase in pressure
shift to the side with fewest moles of gas
,Increase concentration
shift to the side with fewest moles of gas
Removing product
The equilibrium shifts to the right (towards the products) to replace what was
removed.
Increasing temperature
Equilibrium shifts in the endothermic direction
How is crude oil made
Millions of years ago, plankton died and was buried under layers of sediment. The
heat and pressure caused it to turn into crude oil.
Hydrocarbons
molecules made of only carbon and hydrogen
, Alkanes
a hydrocarbon containing only single covalent bonds
CnH2n+2
Types of alkanes
methane - 1 carbon
ethane - 2 carbons
propane - 3 carbons
butane - 4 carbons
Fractional distillation
A method used to separate a mixture of liquids (usually hydrocarbons) based on
their different boiling points.
How fractional distillation works
Crude oil is heated until it evaporates (turns into vapour).
Vapour enters the fractionating column, which is hot at the bottom and cooler at the
top.
Vapours rise up the column.
Different hydrocarbons condense at different levels (depending on their boiling
point):
Calculate rate of reaction
change in quantity/time
How to increase rate of reaction
increase surface area/concentration/pressure
increase temperature
catalyst, reduce activation energy
Reversible reaction
a chemical reaction in which the products re-form the original reactants
Le Chatelier's Principle
States that if a stress is applied to a system at equilibrium, the system shifts in the
direction that relieves the stress.
Increase in pressure
shift to the side with fewest moles of gas
,Increase concentration
shift to the side with fewest moles of gas
Removing product
The equilibrium shifts to the right (towards the products) to replace what was
removed.
Increasing temperature
Equilibrium shifts in the endothermic direction
How is crude oil made
Millions of years ago, plankton died and was buried under layers of sediment. The
heat and pressure caused it to turn into crude oil.
Hydrocarbons
molecules made of only carbon and hydrogen
, Alkanes
a hydrocarbon containing only single covalent bonds
CnH2n+2
Types of alkanes
methane - 1 carbon
ethane - 2 carbons
propane - 3 carbons
butane - 4 carbons
Fractional distillation
A method used to separate a mixture of liquids (usually hydrocarbons) based on
their different boiling points.
How fractional distillation works
Crude oil is heated until it evaporates (turns into vapour).
Vapour enters the fractionating column, which is hot at the bottom and cooler at the
top.
Vapours rise up the column.
Different hydrocarbons condense at different levels (depending on their boiling
point):
