aqa chemistry paper 2
rate of reaction calculation>>> amount of reactant used or amount of product formed / time
rate of reaction>>> how fast the reactants are changed into products
collision theory>>> the more particles collide the more energy is transferred
the more particles in a certain amount of time the faster the reaction is
activation energy>>> the minimum amount of energy required to start a chemical reaction
catalyst>>> substance that speeds up the rate of a chemical reaction
effect of changing concentration on equilibrium>>> if the concentration of a reactant is
increased, more products will be formed until equilibrium is reached again. If the concentration
of a product is decreased, more reactants will react until equilibrium is reached again
effect of changing pressure on equilibrium>>> an increase in pressure causes the equilibrium
position to shift towards the side with the smaller number of molecules. A decrease in pressure
causes the equilibrium position to shift towards the side with the larger number of molecules
effect of changing temperature on equilibrium>>> if the temperature of an equilibrium system is
increased then the relative amount of products at equilibrium increases for an endothermic
reaction and decreases for an exothermic reaction.
effect of concentration on reaction rate>>> increasing the concentration of reactants in solution
means the reacting particles will be closer together. This means they will collide more often so
there will be a higher rate of successful collisions and a faster rate of reaction
effect of pressure on reaction rate>>> increasing the pressure of gaseous reactants means the
reacting particles will be closer together. This means they will collide more often so there will be
a higher rate of successful collisions and a faster rate of reaction
effect of surface area on reaction rate>>> increasing the surface area of the reactants means there
are more exposed reacting particles. This means there are more frequent successful collisions so
the rate of reaction increases.
effect of temperature on reaction rate>>> increasing the temperature means the particles will
have more kinetic energy and so will move faster. If the molecules are moving faster they will
collide more often and, since they've gained kinetic energy, a larger proportion of the particles
will have at least the activation energy. for both these reasons the rate of reaction increases.
equilibrium>>> when a reversible reaction occurs in apparatus which prevents the escape of
reactants and products, equilibrium is reached when the forward and reverse reactions occur at
exactly the same rate
Le Chatelier's Principle>>> if a reaction at equilibrium is subjected to a change in concentration,
temperature or pressure, the position of equilibrium will move to counteract the change.
reversible reaction>>> reactions in which the products from the reaction can react together to
form the original reactants. the direction of reversible reactions can be changed by changing the
conditions
alkanes>>> a hydrocarbon containing only single covalent bonds
the most common hydrocarbon found in crude oil. alkanes have the general formula CnH 2n+2
alkenes>>> hydrocarbons with one or more carbon-carbon double bonds
combustion>>> combustion of hydrocarbon fuels releases energy. during combustion, the carbon
and hydrogen in the fuels are oxidised
, complete combustion>>> water and carbon dioxide are the only products of the complete
combustion of a hydrocarbon.
crude oil>>> a finite resource found in rocks. it is the remains of an ancient biomass consisting
mainly of plankton that was buried in mud. most of the compounds in crude oil are
hydrocarbons.
factors affecting>>> concentration, surface area, catalysts, temperature
addition polymerisation>>> a reaction where many small molecules (monomers) join together to
form very large molecules (polymers)
alcohols>>> alcohols contain the functional group -OH
the first four members of a homologous series of alcohols are methanol, ethanol, propanol and
butanol.
amino acids>>> amino acids have two different functional groups in a molecule they react by
condensation polymerisation to produce polypeptides
carboxylic acids>>> carboxylic acids have the functional group -COOH
the first four members of a homologous series of carboxylic acids are methanoic acid, ethanoic
acid, propanoic acid and butanoic acid
catalytic cracking>>> long-chain hydrocarbons are heated to turn them into a gas
the vapour is then passed over a hot powdered aluminium oxide catalyst
the long chain molecules split apart on the surface of the catalyst
condensation polymerisation>>> these reactions involve monomers with two functional groups
when these monomers react they join together and lose small molecules such as water
cracking>>> a process that involves breaking down larger hydrocarbons to produce smaller more
useful molecules
cracking can be done by catalytic cracking or steam cracking
DNA>>> DNA encodes genetic instructions for the development and functioning of living
organisms and viruses
most DNA molecules are two polymer chains, made from four different nucleotides, in the form
of a double helix
esters>>> the product of a condensation reaction between a carboxylic acid and alcohol. For
example: ethanol + ethanoic acid → ethyl ethanoate
fermentation>>> a chemical process by which molecules such as glucose are broken down
anaerobically
ethanol is produced when sugar solutions are fermented using yeast
fractional distillation>>> a method of separating a mixture of substances according to their
different boiling points
commonly used to separate crude oil into different fractions
homologous series>>> a series of compounds with the same functional group and similar
chemical properties
hydrocarbons>>> molecules that are made up of hydrogen and carbon atoms only
nucleotides>>> the monomers which make up DNA
polyesters>>> a category of polymers which contain the ester functional group in their main
chain
formed from condensation polymerisation
polymers>>> large long-chain molecules made up of lots of small monomers joined together by
covalent bonds
polypeptide>>> a chain of amino acids
rate of reaction calculation>>> amount of reactant used or amount of product formed / time
rate of reaction>>> how fast the reactants are changed into products
collision theory>>> the more particles collide the more energy is transferred
the more particles in a certain amount of time the faster the reaction is
activation energy>>> the minimum amount of energy required to start a chemical reaction
catalyst>>> substance that speeds up the rate of a chemical reaction
effect of changing concentration on equilibrium>>> if the concentration of a reactant is
increased, more products will be formed until equilibrium is reached again. If the concentration
of a product is decreased, more reactants will react until equilibrium is reached again
effect of changing pressure on equilibrium>>> an increase in pressure causes the equilibrium
position to shift towards the side with the smaller number of molecules. A decrease in pressure
causes the equilibrium position to shift towards the side with the larger number of molecules
effect of changing temperature on equilibrium>>> if the temperature of an equilibrium system is
increased then the relative amount of products at equilibrium increases for an endothermic
reaction and decreases for an exothermic reaction.
effect of concentration on reaction rate>>> increasing the concentration of reactants in solution
means the reacting particles will be closer together. This means they will collide more often so
there will be a higher rate of successful collisions and a faster rate of reaction
effect of pressure on reaction rate>>> increasing the pressure of gaseous reactants means the
reacting particles will be closer together. This means they will collide more often so there will be
a higher rate of successful collisions and a faster rate of reaction
effect of surface area on reaction rate>>> increasing the surface area of the reactants means there
are more exposed reacting particles. This means there are more frequent successful collisions so
the rate of reaction increases.
effect of temperature on reaction rate>>> increasing the temperature means the particles will
have more kinetic energy and so will move faster. If the molecules are moving faster they will
collide more often and, since they've gained kinetic energy, a larger proportion of the particles
will have at least the activation energy. for both these reasons the rate of reaction increases.
equilibrium>>> when a reversible reaction occurs in apparatus which prevents the escape of
reactants and products, equilibrium is reached when the forward and reverse reactions occur at
exactly the same rate
Le Chatelier's Principle>>> if a reaction at equilibrium is subjected to a change in concentration,
temperature or pressure, the position of equilibrium will move to counteract the change.
reversible reaction>>> reactions in which the products from the reaction can react together to
form the original reactants. the direction of reversible reactions can be changed by changing the
conditions
alkanes>>> a hydrocarbon containing only single covalent bonds
the most common hydrocarbon found in crude oil. alkanes have the general formula CnH 2n+2
alkenes>>> hydrocarbons with one or more carbon-carbon double bonds
combustion>>> combustion of hydrocarbon fuels releases energy. during combustion, the carbon
and hydrogen in the fuels are oxidised
, complete combustion>>> water and carbon dioxide are the only products of the complete
combustion of a hydrocarbon.
crude oil>>> a finite resource found in rocks. it is the remains of an ancient biomass consisting
mainly of plankton that was buried in mud. most of the compounds in crude oil are
hydrocarbons.
factors affecting>>> concentration, surface area, catalysts, temperature
addition polymerisation>>> a reaction where many small molecules (monomers) join together to
form very large molecules (polymers)
alcohols>>> alcohols contain the functional group -OH
the first four members of a homologous series of alcohols are methanol, ethanol, propanol and
butanol.
amino acids>>> amino acids have two different functional groups in a molecule they react by
condensation polymerisation to produce polypeptides
carboxylic acids>>> carboxylic acids have the functional group -COOH
the first four members of a homologous series of carboxylic acids are methanoic acid, ethanoic
acid, propanoic acid and butanoic acid
catalytic cracking>>> long-chain hydrocarbons are heated to turn them into a gas
the vapour is then passed over a hot powdered aluminium oxide catalyst
the long chain molecules split apart on the surface of the catalyst
condensation polymerisation>>> these reactions involve monomers with two functional groups
when these monomers react they join together and lose small molecules such as water
cracking>>> a process that involves breaking down larger hydrocarbons to produce smaller more
useful molecules
cracking can be done by catalytic cracking or steam cracking
DNA>>> DNA encodes genetic instructions for the development and functioning of living
organisms and viruses
most DNA molecules are two polymer chains, made from four different nucleotides, in the form
of a double helix
esters>>> the product of a condensation reaction between a carboxylic acid and alcohol. For
example: ethanol + ethanoic acid → ethyl ethanoate
fermentation>>> a chemical process by which molecules such as glucose are broken down
anaerobically
ethanol is produced when sugar solutions are fermented using yeast
fractional distillation>>> a method of separating a mixture of substances according to their
different boiling points
commonly used to separate crude oil into different fractions
homologous series>>> a series of compounds with the same functional group and similar
chemical properties
hydrocarbons>>> molecules that are made up of hydrogen and carbon atoms only
nucleotides>>> the monomers which make up DNA
polyesters>>> a category of polymers which contain the ester functional group in their main
chain
formed from condensation polymerisation
polymers>>> large long-chain molecules made up of lots of small monomers joined together by
covalent bonds
polypeptide>>> a chain of amino acids
