⚛ Chemistry Paper 2 Flashcards
chem: what is a monomer
a molecule that can bond to other monomers to make polymers
chem: what type of atom are monomers often seen as
they are often alkenes (methane)
chem: how strong are the intermolecular forces of attraction in polymers
strong
Chem: why do polymers have higher melting and boiling points that smaller molecules
Because they have stronger intermolecular forces
Chem: why do polymers have higher melting and boiling points that smaller molecules
Because they have stronger intermolecular forces
chem: in polymers are covalent bonds weak or strong
they are extremily strong
Chem: what are the 2 principles of Le Chateliers Principle
- If the conditions change then the posision of equalibrium changes
- If the conditions change then the system responds to counteract the change.
Chem: what does equilibrium mean
The forward and reverse reactions occur at the same rate in a closed system
Chem: for equilibrium, does the amount of products and reactants have to be equal
No the only must remain the same, individually
Chem: what is dynamic equilibrium
It is equilibrium where both froward and backward reactions are still happening, the rates of forward and reverse reactions are the same, concentrations of chemicals do not change and it only happens in a closed system
Chem: what is collision theory
A theory that for a reaction to occurr particles must collide with enough energy
Chem: what explains why reactions happen at different rates
Collision theory
Chem: what are alkanes
They all end in ‘ane’
They are hydrocarbons
There formula is CnH2n+2
Chem: what are hydrocarbons
They are molecules made up of hydrocarbons
Chem: what is crude oil found in
Rocks (The Earth’s Crust)
Chem: what are the properties of hydrocarbons, with increasing size
- Boiling point increases with molecular size
- Viscosity increases with molecular size
- Flammability decreases with molecular size
Chem: what happens to the position of equilibrium when you increase pressure
Shift in the direction of the reaction that produces the fewest gas molecules
Chem: what happens to the position of equilibrium when you decrease pressure
Shifts toward the reaction the produces the most gas
Chem: what happens to the position of equilibrium when you increase concentration of the reactant
Shifts the equilibrium position toward the products
Chem: what happens to the position of equilibrium when you decrease concentration of the reactants
Shifts towards the reactants
Chem: what happens to the position of equilibrium when you increase temp
Shifts to endothermic
Chem: what happens to the position of equilibrium when you decrease temp
Shifts to the Exothermic
Chem: what is crude oil made of
It is a mixture of lots of compounds, many hydrocarbons
Chem: what is fractional distillation in relation to crude oils
It is the process of separating crude oil into groups of hydrocarbons with similar numbers of carbon atoms, these groups of hydrocarbons are called fractions
Chem: what are hydrocarbons with lots of carbon atoms called
Long chain hydrocarbons
Chem: what are hydrocarbons with little amounts of carbon atoms called
Short chain hydrocarbons
Chem: what do all organic compounds contain
Carbon
Chem: what is the equation for burning hydrocarbons when there is plenty of oxygen
- energy is released
- carbon dioxide and water is produced
Chem: what happens when there is not enough oxygen when burning hydrocarbons
Carbon monoxide is produced
Chem: what are the properties of heavy fractions of crude oil
- don’t ignite easily
- high boiling points
- low volatility
Chem: what is cracking
It is the process of breaking down long chain hydrocarbons into short chain hydrocarbons and alkenes that are more useful, it is thermal decomposition
Chem: what is catalytic cracking
Vaporised heavy hydrocarbons are passed over the top of a heated catalyst, this produces alkanes and alkenes, e.g. hexane -> butane + ethane, it is preferred in industry as it produces more useful petrol at lower tamps and pressures.
Chem: what is steam cracking
Vaporised heavy hydrocarbons are combined with steam at high temperatures, it produces alkenes and alkanes.
Chem: what are some uses of hydrocarbons
- being starting materials for chemicals like ethanol
- being combined to make polymers
Chem: how does fractional distillation of crude oil happen
- crude oil is vaporised and enters a fractioning column
- vapours condense at different points and are collected as fractions at these points
Chem: what is diesel oil used in
Cars and trains
Chem: what is kerosine used for
Jet fuel
Chem: what is heavy fuel oil used for
Fuel on ships and in power stations
Chem: what are liquified petroleum gasses used for
Fuels
Chem: what is a homologous series
It is a series of compounds that can be represented by a formula
Chem: why do alkanes have higher melting and boiling points the larger they are
They have more covalent bonds so there are more intermolecular forces to overcome to changed the state and so more energy is required
Chem: What property of bonds do alkenes have
They are unsaturated as they have a double carbon bond
Chem: what is a fractioning column and what is it used for
It a piece of equipment used in the fractional distillation of crude oils
Chem: what is the general formula of alkenes
Chem: are alkenes reactive
in realtion to alkanes
Their double carbon bond means they are more reactive that the alkanes
Chem: what are the 4 smallest alkenes, in order for smallest to largest
Ethene (2 carbon), propene, butene, pentene (5 carbon)
Chem: how many carbon atoms does pentene have
5
Chem: what is a functional group
A collection of atoms in an organic molecule that affects its reaction e.g. the functional group I alkenes is the carbon carbon double bond
Chem: what is a typical reaction for an alkene
Addition
Chem: what happens when alkenes react with oxygen
They combust and it is incomplete combustion so burn with a smoky flame
Chem: what happens when alkenes react with water when a nickel catalyst is present
When a nickel catalyst is present
Chem: what happens when an alkene reacts with water with a phosphoric acid catalyst present
When a Phosphoric acid catalyst is present
Chem: how do you test for alkanes and alkenes
You add the thing you want to test to a bromine water solution and shake, nothing will happen when an alkane is present but the solution will change from orange brown to colourless when an alkene is present because the double bond opens
Chem: what is the function group of alcohols
-OH
Chem: what is the general formula for alchohol
Chem: what are the 4 smallest alcohols from smallest to largest
Methanol, ethanol, propanol, butanol
Chem: what happens when water reacts with alchohol
They dissolve to give neutral solutions
Chem: what happens when alchohol reacts with sodium
A metal salt and hydrogen is produced
Chem: what happens when alchohol reacts with air
They combust completely
chem: what does fermentation produce
ethanol
chem: what is the process of fermnetation
- add yeast to a sugar solution
- reaction occurs
- the reaction gives a cloudy solution of ethanol and carbon dioxide
chem: what are the ideal conditions for fermentation
- 37 degrees
- slightly acidic
- absence of oxygen
chem: what is the general formula for carboxylic acids
chem: what is the functional group of carboxylic acids
-COOH
chem: what type of acid is a carboxylic acid
it is a weak acid as it only partially ionises in water
chem: what are the 4 smallest carboxylic acids
methanoic acid, ethanoic adic, propanoic acid, butanoic acid
chem: what happens when a carboxylic acid reacts with a carboate
products:
- water
- salt
- CO2
chem: what happens when a carboxylic acid reacts with water
they dissolve to give a solution with an acidic PH
chem: what happens when a carboxylic acid reacts with alchohols and an acid catalyst
products:
- an ester
- water
chem: what is Addition polymerization
it is the joining of 2 short chain monomers to form a long chain polymer
chem: what are the monomers used in Addition polymerisation and why
alkenes because the double carbon bonds can open and allow multiple alkenes to join together
chem: how do you name addition polymers
you start with poly and then put in the name of the monomer
chem: what is condensation polymerisation
it is the process of joining together 2 monomers with functional groups producing a polymer and small molecule biproducts such as water usually
chem: what is the simplist type of condensation polymerisation
combining 2 monomers with the same functional group
chem: what are amino acids
they are organic ocmpunds with 2 different functional groups
chem: how can amino acids be combined
through condensation polymerisation
chem: when amino acids are combined using condenstation polymerisation what are the products
- a polypeptyide
- water
chem: what happens whe one or more polypeptide becomes associated
a macromolecule alos known as a protien is formed
chem: what is a covalent bond that forms between the amine and carboxyl groups called
a peptide links
chem: what are the monomers found in DNA called
nucleotides
chem: what are the 4 nucleotides called
- Adenine
- Thymine
- Cytosine
- Guanine
chem: what is the shape of DNA
it is 2 polymer chains arranged in the form of a double helix
chem: what are 2 naturally occuring polymers steming from sugars
cellulose, starch
chem: what are 3 properties that make good fuel
- high melting and boiling points
- high volatility
- high flamability
chem: how do you find if a substance is pure
if it has the exact, correct and specific melting and boiling point
chem: what will more impurities in a substance cause
the range of temperatures at which the substance will melt and boil
chem: what is a formulation
they are mixtures of chemicals that are designed for a specific function, paint is one example
chem: what are the 2 phases of chromatography
- mobile phase, this phase is where the liquid or gas moves and substances are picked up and carried
- stationary phase, this is where the substance does not move
chem: in chromatography, if a substance moves far which fase is it attracted to
the mobilephase
chem: in chromatography, if a substance dosent move far which phase is it attracted to
the stationary phase
chem: what is the test for hydrogen
place a lighted splint near the mouth of a test tube containing the unknown gas, if you hear a squeaky pop then hydrogen is present
chem: why is the noise heard when testing for hydrogen
because the hydrogen is burning rapidly in the presence of oxygen
chem: how do you test for oxygen
- light a splint
- wait for it to go out but still be glowing
- movet he splint into the container of gas
- if the splint relights then oxygen is present
chem: how do you test for carbon dioxide
- setup a test tube of lime water with a tube that gas can be thread through in it, below the liquid line
- feed the gas through the tube, if the lime water turns cloudy then CO2 is present
chem: how do you test for chlorine
- insert damp blue litmus paper into a container of gas
- if the litmus paper bleaches and turns from red to white then chlorine is present
chem: what is the flame test
some metal ions can be distinguished based on the colour fo their flame, burning the metal can help to determine what it is
chem: with what colour does a posotive lithium ion burn
crimson
chem: with what colour does a posotive sodium ion burn
yellow
chem: with what colour does a posotive potassium ion burn
lilac
chem: with what colour does a posotive calcium ion burn
orange-red
chem: with what colour does a posotive copper ion burn
green
chem: what happens to some aqueous metal ions when they are reacted with a sodium hydroxide (NaOH) solution
they form insoluable solids called precipitates that (for gcse) are metal hydroxides
chem: what 3 metals can be removed from aqueous solutions by reacting them with sodium hydroxide
- calcium
- magnesium
- aluminium
chem: what colour are calcium, magnesium and aluminium hydroxide precipitates and why
white (they are not transition metals)
chem: what colour precipitate is formed when aqueous Copper(II) is reacted with NaOH
blue
chem: what colour precipitate is formed when aqueous Iron(III) is reacted with sodium hydroxide
brown
chem: what colour precipitate is formed when aqueous Iron(II) is reacted with NaOH
green
chem: how do you test for carbonates
react carbonates with dilute acids to form carbon dioxide + salt + water, as the carbon dioxide is produced it can be bubbled into limewater to check if it is indeed carbon dioxide
chem: how do you test for halides
- add dilute nitric acid to the solution
- add silver nitrate ions
- the halide will form a precipiatate with the silver ions if it is a halide
chem: what is a halide
it is a compoud containing a halogen ion
chem: what colour is silver chloride
white
chem: what colour is silver bromide
cream
chem: what colour is silver iodide
pale yellow
chem: what are sulfates
chem: how do you test for sulfates
- add dilute hydrochloric acid to a solution to remove carbate ions
- add barium chloride, if sulfates are present then a white precipitate will be formed
Chem: what is hydrogenisation
It is the process of combining hydrogen and alkenes to form alkanes
Chem: how are alcohols produced with alkenes
Alkene + water (steam) -> alcohol
Phosphoric acid catalyst
Chem: how are halogenalkanes
Halogen + alkene -> halogenalkanes
Chem: what happens when alkenes react oxygen
Alkene + oxygen -> combustion
chem: what happens during an alkene addition reaction
their double carbon bonds open up allowing the carbon atoms to bond with new atoms
chem: what is it called when atoms hydrogen atoms are added across a double carbon bond
hydrogenisation
chem: what is a hydroxyl group
it is the functional group of alchohols and is -OH
chem: what is a carboxyl group
it is the functional group of carboxylic acids and is -COOH
Chem: what is the name given to groups of hydrocarbons (based on their chain length)
Fractions
Chem: what type of crude oil fraction makes bad fuels
Heavy fractions
Chem: over the evolution of the earth how did the gas proportions change
Chem: what is an evaluate question
A question that requires you to say something is better than another thing.
Chem: what 2 pollutants does to incomplete combustion cause
- carbon monoxide
- particulates
Chem: how do Sulfur impurities cause an environmental effect
Sulphur impurities are in all fossil fuels, when burned it oxidises forming a toxic gas
Chem: how do internal combustion engines cause the production of a toxic gas
When fossil fuels are burned at high temps in a confined space nitrogen and oxygen react to form oxides of nitrogen which are toxic
Chem: what environmental effect does increased levels of particulates cause
Increased global dimming
Chem: what environmental effects do both Sulfur and nitrogen oxides have
- when inhaled they cause respiratory issues
- they can react with water to for sulphuric acid and nitric acid that cause acid rain
Chem: how do the oceans remove carbon dioxide from the atmosphere
- Carbon dioxide dissolves in the oceans
- when it is in this state it can react with water to give carbon precipitates
Chem: how do marine animals remove carbon form the atmosphere
Marine animals remove carbonates from the oceans to build their shells and skeletons
Chem: how many double bonds do alkenes have
All alkenes only have one double bond
Chem: carboxylic acid + alcohol ->
Ester
Chem: why can giant ionic compounds not conduct when solid
Because the ions are not free to move
Chem: what are precipitates (for GCSE)
Metal hydroxides
Chem: what is a reference substance in paper chromatoegraphy
It provides an indication of substance presence, they are pure substances run alongside the solution
Chem: what is the product of ethanoic acid + ethanol
Ethyl ethanoate (ester) + water
Chem: how are esters formed
Alchohol + carboxylic acid
Chem: what is the ending for carboxylic acids
for naming
anoic, ethanoic acid
Chem: using flame tests, why might it be hard to test metals in a mixture
Because some colours might overshadow others
Chem: what is the pattern of light that an element gives off called
A line spectrum
Chem: how do emission spectra work
- Heat causes an element to give off light
- Each element gives off a different pattern of light (this is a line spectrum)
- Not all of the light is visible
- A prism is used to split the light, spectroscopy
- The pattern is used to identify different chemichals
Chem: what are the aspects of spectrocpscopy
- more accurate
- highly sensitive
- quicker
- small samples
Chem: what are the pros of flame tests
- Cheaper
- Less training
Chem: what is spectroscopy
The process of splitting light with a prism into a spectrum
Chem: what is different about aluminium in the sodium hydroxide tests (when sodium hydroxide is in excess)
It dissolves
Chem: when you mix chloride ions with silver nitrate and nitric acid what happens
White precipitates
Chem: when you mix bromide ions with silver nitrate and nitric acid what colour percipitate is formed
Cream precipitates
Chem: when you mix iodide ions with silver nitrate and nitric acid what happens
Yellow precipitates
Chem: what is bronze an alloy of
Copper and zink
Chem: what is brass an alloy of
Copper and tin
Chem: what is brass an alloy of
Copper and zinc
Chem: what are steels alloys of
Iron and carbon and/or other metals
Chem: what are steels alloys of
Iron and carbon and/or other metals
Chem: what is bronze used for
- electrical hardware
- statues
- coins
Chem: what is tins effect in bronze
It increases hardness
Chem: in brass what does zinc do
It makes the material more malliable
Chem: what is brass used for
- hinges
- plug sockets
- locks
Chem: why are gold alloys made
Because they are more resilliant, 24 carrots is pure gold and 12 carrots is 50%
Chem: what is high carbon steel used for and what are its properties
It is used for cutting tools and blades and it strong and brittle
Chem: what is low carbon steel used for and what are its properties
Making car bodies, soft and malliable
Chem: what do stainless steels do and what are they made of
They are used in cutting utensils and cutlery and are made of chromium and nikel, iron and carbon
Chem: what are the properties of stainless steel
Strong and resistant to corrosion
Chem: what is corrosion
It is the destruction of a material by reaction with water and/or oxygen
Chem: what is rusting
It is the corrosion or iron or steel
Chem: how is corrosion prevented with protective layers, some examples
They block the water or air from reaching the material the can corrode, layers include:
- plastic/metal coating
- oil
- paint
Chem: what are the problems that sulfur dioxide can cause
- acid rain
- respiratory problems
Chem: how is sewage water treated to remove organic matter
- it is filtered
- sedimentation is used to produce sewage sludge and effluent
- anaerobic digestion of solid sewage sludge
- aerobic biological treatment of liquid effluent
Chem: how can alkenes form alkanes
Nitric acid catalyst, react with water
Chem: how do alkenes form alcohols
Phosphoric acid catalyst reaction with steam
Chem: what is the haber process
- It is a process that makes ammonia
- it uses the reversible reaction of nitrogen and hydrogen as shown below
Chem: what are the steps of the haber process
- Nitrogen and hydrogen are pumped through piped and the pressure of the mixture is increased to 200 atmospheres with an iron catalyst
- The pressurised gas is heated to 450 degrees and is passed through a tank containing an iron catalyst
- Mixture is cooled, ammonia liquifies and is collected, excess gasses and recycled
Chem: what are some uses of ammonia
- making fertilisers
- explosives
- dyes
Chem: what is potassium used for in plants
Needed in enzymes involved in respiration and photosynthesis
Chem: what is phosphorus used for in plants
To make more dna and cell membraines
Chem: what is phosphate rock
It is a source of insolable phosphorus
Chem: phosphate rock + nitric acid
Phosphoric acid + calcium nitrate
Chem: phosphate rock + nitric acid
Phosphoric acid + calcium nitrate
Chem: phosphate rock + sulfuric acid
Single supersulfate
Chem: phosphate rock + phosphoric acid
Triple supersulfate
Chem: what are the 2 main sources of potassium in fertilisers
- potassium sulphate
- Potassium chloride
Chem: what are the 2 main sources of potassium in fertilisers
- potassium sulcate
- Potassium chloride
Chem: how does sacrificial coating prevent corrosion
Placing a more reactive element over a less reactive one can protect that one by letting the more reactive corrode, magnesium added to train tracks to protect them
Chem: what gas that can be harmful to the atmosphere can be released by internal combustion engines
Nitrogen dioxide can be released by internal combustion engines, this gas is toxic
Chem: what is the issue with sulfur dioxide
It is toxic
Chem: why would the concentration of ions not decrease when a solution is filtered
Because the ions are in a solution and so the filter cannot filter them out
Chem: what is the process for the greenhouse effect
- The sun emits short wavelength radiation such as UV
- The earth absorbs and emits long wavelength radiation and the upper atmosphere heats up
- Greenhouse gasses absorb some of the long wavelength radiation
- These greenhouse gasses re-radiate this thermal radiation in all directions, some of this radiation goes back into the atmoshpere and warms up the lower atmosphere
Chem: what 4 things decrease atmospheric carbon
- carbon dioxide can be dissolved in the oceans and can then react in this state with water to give carbon precipitates
- photosynthesis
- marine animals, they can remove carbonates from ocean to build their shells and skeletons
- peat bogs
Chem: how does the earths atmosphere change over time
- Volcanoes release carbon dioxide, water vapour and nitrogen into the atmosphere
- Water vapour condenses and falls as rain, oceans are formed
- Algie form and begin to photosynthesise, releasing oxygen
- Oxygen levels increased
- Levels of carbon dioxide dropped as the carbon dioxide becomes trapped
Chem: what are the properties of alkenes
- they have higher reactivity than alkanes
- Higher melting and boiling points
- greater flammibility
Chem: what can make something a thermal conducter
Delocalized electrons
Chem: for a carboxylic acid to react with an alcohol what type of acid must be present
Acid catalyst
Chem: when plotting a graph if a coordinate is 0,0 what do you do with it
PUT A CROSS ON IT
Chem: name the monomers from which starch are produced
Glucose
Chem: name the monomers from which protiens are produced
Amino acids
Chem: what are the reactants that produce ethyl ethanoate + water
Ethanoic acid + ethanol
Chem: in the sulphate and halide ion tests what is the catalyst
Acids
Chem: why does limewater go cloudy
When it reacts with carbon dioxide calcium carbonate, a precipitate is formed
Chem: what catalysts are used in processes that produce ammonia
iron
Chem: how do alcohols produce carboxylic acids
In the presence of strong oxidising agents alcohols react (with the oxidising agents) to form carboxylic acids
Chem: what are ceramics
Ceramics are inorganic, non-metallic solids
Chem: what are 2 examples of ceramics
- glass
- pottery and bricks
Chem: what is most of the glass that we use
Soda lime glass
Chem: how is soda lime glass produced
By combining limestone, sodium carbonate, and sand and heating the mixture
Chem: what is a non soda lime type of glass that you have to know for gcse
pyrex
Chem: how is pyrex produced
Sand and boron trioxide are combined and heated to a greater temp than required for soda lime glass
Chem: what is pyrex used for
Chemical glassware and kitchemware add why
Chem: what are the ammonia containing compounds used in fertilisers and how are they made
- ammonium nitrate - ammonia + nitric acid
bio: what are 3 roles of proteins in the body
- enzymes
- haemoglobin
- antibiodies
Chem: what are esters used for
- perfumes
- flavourings
- industrial solvents
Chem: what is the functional group for esters
-COO
Chem: how are esters named
- Remove anol from the alcohol and add -yl
- Change the same of the parent acid to endo in -oate
- Alcohol names top the front and acid to the back
Chem: how is solid sewage sludge digested
With anaerobic digestion
Chem: how is liquid effluent treated
Aerobic biological treatment
Chem: how is soot formed during combustions
During incomplete combustion some carbon is not fully oxidised and so could become carbon monoxide or soot or a mixture
Chem: what is soot
Particulate carbon
Chem: how is acid rain formed
- all rain is slightly acidic due to dissolved carbon dioxide
- sulfur dioxide and nitrogen oxides can dissolve in droplets of water (rain) to form sulfuric acids
Chem: what are nitrogen monoxide and dioxide referred to as
Chem: what are the effects of acid rain
- buildings and statues are damaged when it reacts with metals and rocks, especially those made of limestone (calcium carbonate)
- it damages the waxy layer of leaves of trees which makes it more difficult for them to absorb minerals needed for them to grow
- it also makes rivers and lakes more acidic, meaning some aquatic life cannot survive
Chem: what is limestone
Sodium carbonate
Chem: what are supersulfates used for
They are used as a source of phosphorus for fertilisers
Chem: when carboxylic acids react with baces what happens
They neutralise to form salt and water
Chem: when carboxylic acids react with long chain fatty acids what jappens
(the salt) Soap is made
Chem: what is an example of an oxidising agent that can be used to make an alcohol init a carboxylic acid
acidified potassium dichromate solution
Chem: what are most of the hydrocarbons in crude oils
alkenes
Chem: what are 2 things that humans do that release methane
- agriculture
- burning fossil fuels
Chem: what are the properties of carbon monoxide
- it is colourless
- odorless
- it bonds to the haemoglobin in the blood instead of oxygen
Chem: what are the 3 units of rate of reaction
- g/s
- cm3/s
- mol/s
Chem:
Chem: what happens to a catalyst during a chemical reaction
It changes the reaction pathway but is not used up during the reaction
Chem: what do catalysts do to the rate of reaction
They speed up the chemical reaction so increase the rate of reaction
Chem: what apparatus must be used to reach equilibrium in a chemical reaction
One that does not allow any reactants and products to esacpe
Chem: what can fractions of crude oils be processed to produce
- feedstock for the petrochemical industry
- fuels
Chem: what are some examples of products produced by the petrochemical industry
- solvents
- lubricants
- polymers
- detergents
Chem: during combustion what chemicals are oxidised
- carbon and hydrogen
Chem: what are the 2 products of cracking that you must know
- alkenes
- alkanes
Chem: what are the 5 chemicals that you must know add to alkenes
- hydrogen
- water
- chlorine
- bromine
- iodine
Chem: when sugar solutions are fermented what is produced
Aqueous solutions of ethanol
Chem: what can alcohols be used for
- they can be used as solvents because they can dissolve substances such as oils and fats and also most of the substances that water can
- the first 4 can be used as fuels
- they dissolve in water to form neutral solutions
Chem: what are some polymers that are important for life
- proteins
- starch
- cellulose
Chem: name some formulations
- fuels
- cleaning agents
- paints
- medicines
- alloys
- fertilisers
- foods
Chem: what chemical used in NPK fertilisers can be obtained through mining, and which of these cannot be used directly in fertilisers
- phosphate rock, this can not be directly used as in fertilisers
- potassium chloride
- potassium sulphate
Chem: what are the 3 chemicals made from phosphate rock that can be used in fertilisers
- single super sulfate
- triple super sulphate
- phosphoric acid
Chem: what are NPK fertilisers
They are fertilisers that contain compounds of nitrogen, phosphorus and potassium
Chem: what type of chemical are NPK fertilisers
They are formulations
Chem: what is pyrex also called
Borasilicate glass
Chem: how are clay ceramics made
They are made by shaping wet clay and then heating in a furnace
Chem: what things do the properties of polymers depend on, what is an example
- the conditions under which they are made
- the monomers they are made from
- low density (LD) and high density (HD) poly(ethene), they are both produced by ethene
Chem: what type of polymers melt when they are heated
Thermosoftening polymers
Chem: what type of polymers do not melt when they are heated
Thermosetting polymers
chem: what density are aluminium alloys
They are low density
Chem: what 3 materials are gold jewelry usually alloyed with
- zink
- silver
- copper
Chem: what are most metals used every day
They are mostly metal alloys
Chem: how long ago did algae first produce oxygen
2.7 billion years ago
Chem: what are 3 greenhouse gasses
- water vapour
- methane
- carbon dioxide
Chem: what are the 2 methods of desallination
- distillation
- reverse osmosis
Chem: what chemicals used in NPK fertilisers can be mined
- Phosphate rock
- potassium chloride
- potassium sulfate
Chem: what 2 things can ammonia be used to make
- ammonium salts
- nitric acid
Chem: what are composites
They are materials that contain 2 or more materials with different properties
Chem: what are the 2 materials that more composites are made up of
A matrix or binder that surrounds and binds together fibers of fragments of the other material, called the re-enforcement
Chem: how is low density poly(ethene) made and what are its uses
- it is made at high pressures, over 1000 atmospheres and at 300 degrees C
- it can be used as: plastic water bottles and flexible insulation
Chem: how is high density poly(ethene) made and what are its uses
- ethene molecules are added together with the presence of a catalyst at pressures of 10-80 atmospheres and at 1-200 degrees
- it is used as crates, dust bins and plastic drums
Chem: how is most potable water produced
- an appropriate source of fresh water is chosen
- it is passed through filter beds
- it is then sterilised, with one of: uv light, ozone, chlorine
Chem: what is fresh water
It is water with low levels of dissolved substances
Chem: where does the UK get most of its fresh water
rain
Chem: what are thermosoftening polymers
They melt when heated
Chem: what are thermosetting polymers
They do not melt when heated
Chem: what is the structure of a thermosoftening polymer
They do not have covalent bonds between neighbouring polymer molecules and so the molecules can move over one another when heated
Chem: what is the structure of a thermosetting polymer
crosslinks between molecules do not allow for the polymer to melt
Chem: what are some examples of composites, what are the matrix and binder
- fiberglass, matrix - glass fibers, binder - polymer resin
- re-enforced concrete, matrix - steel, binder - concrete
Chem: what is a reason that scientists believe that humans caused the earths temp to increase
Peer-reviewed evidence
Chem: what type of rocks formation decreases atmospheric carbon
Sedimentary rock and fossil fuels
Chem: what are the gasses other than oxygen and nitrogen in the earths atmosphere that you must know
- carbon dioxide
- water vapour
- noble gasses
Chem: for how long have the proportions of gasses in the atmosphere been roughly similar to what they are now
200 million years
Chem: what are the properties of instrumental methods
They are:
- accurate
- sensitive
- rapid
Chem: what is an example of an instrumental method for checking elements
Flame emission spectroscopy
Chem: what is the process for flame emission spectroscopy
- sample is put into a flame
- the emitted light is passed through a spectroscope
- a line spectrum is made that can be analysed to identify and measure concentrations of metal ions in a mixture
Chem: how will a pure substance show in chromatography
It will be only one spot
Chem: how can proteins be formed from amino acids
Different amino acids are combined in the same chain to produce protiens
Chem: what hydrocarbons do the products of cracking contain
Alkenes and alkanes
Chem: during the combustion of hydrocarbons what happens to the hydrogen
It is oxidised
Chem: what happens to the fuel in chemical cells
The fuel is oxidised electrochemically, this produces the potential difference
Chem: what are an alternative to hydrogen fuel cells
Rechargeable cells
Chem: what are some exothermic reactions
- combustion
- neutralistaion
- many oxidation reactions
Chem: with the increasing size of small molecules what force also increases
Intermolecular forces of attraction
Chem: what is DNA (deoxyribonucleic acid)
It is a large molecule essential for life, it encodes genetic instructions for the development and functioning of living organisms and viruses
Chem: what must be in excess for aluminium to re dissolve into sodium hydroxide
Sodium hydroxide
Chem: why is it difficult to mode climate change and what affects does this have
- it is difficult because the problem is global
- this leads to simplified models that can mean that the media may present speculations and opinions based on only parts of the evidence
Chem: why are peer review and communication of findings important (set card as 4 if know well)
Because it allows for correct, corroborated evidence to be shared
Chem: what does an increasing of global temperatures cause
Climate change
Chem: what are 4 potential effects of climate change
- rising sea levels
- extinction of species
- more extreme weather
- affected food security
- any other valid effect #
Chem: copper ores are becoming more scarce, what are 2 alternatives of mining for copper
- phytomining
- bio leaching
Chem: what does the reduction and recycling of materials by the end user reduce
- the use of limited resources
- the use of energy sources
- waste
- environmental impacts
Chem: what are metals, glass, ceramics and most plastics made from and where does the energy come from
limited raw materials, the energy for the processes comes, mostly, from limited resources
Chem: what does obtaining raw materials from the earth by quarrying cause
Environmental impacts
Chem: how are glass bottles re-used
Glass bottles are crushed and melted to make other glass products
Chem: when materials cannot be reused (e.g. glass bottles turned back into glass) what can be done with them
They can be recycled - used for another use after the primary use
Chem: how can metals be reused
They can be melted and recast or reformed into different products, the amount of separation needed depends on the material and properties of the final product
Chem: what is an example of a process by which metals are recycled
Scrap steel can be added to iron from a blast furnace to reduce that amount of iron needed to be extracted from ore
Chem: what are some materials that are formed from carbon dioxide
- limestone
- coal
- crude oil
- natural gas
Chem: what was the early earth atmosphere similar to
It was similar to the atmospheres of mars and Venus as they are today
Chem: what is phytomining
It is where metal compounds are extracted by using plants to absorb the metal compounds, harvesting them and burning them to produce ash that contains metal compounds
Chem: what is bioleaching
It is where bacteria are used to produce leachate solutions that contain metal compounds
Chem: to collect the metals after bioleaching and phytomining what must be done
The compounds must be processed to obtain the metal
Chem: what is an example of a process used after phytomining or bioleaching that can be used to process copper compounds
Coppre can be obtained from solutions of copper compounds by displacement using scrap iron or by electrolysis
Chem: what are 2 ways of extracting copper from low grade ores
Phytomining and bioleaching
Chem: why are bioleaching and phytomining used instead of traditional mining methods for copper
Because copper ores are becoming scarce
Bio: how do you calculate that change in bond energy
Bond energy of reactants - bond energy of products = change in bond energy
Chem: what is stainability
It is meeting the needs of the present without compromising future generations
Chem: when describing how to make potable water what sources of water can you talk about
- rivers
- groundwater
Check for more
Chem: in relation to energy consumption, what are processes used to desalinate water
They are energy intensive, this is what makes them expensive/costly
Chem: what is repeatable
You can repeat the experiment, check
Chem: what is reproducible
S9meone else can repeat the same experiment with similar or the same results, check
chem: why is a high temp used in the haber process
- forward reaction in exothermic, increasing temp moves the position of equilibrium towards the reactants
- there is a tradeoff between increasing the rate of reaction and reducing the yield (due to the high temp)
chem: why is a pressure of 200 atmos used in the haber process
- there are fewer molecules of product than reactant, increasing the pressure moves the position of equilibrium towards the products
- increasing the pressure can be expensive and dangerous so 200 atmos is a happy balance
check these 2 with miss
