Chemistry Paper 2 Flashcards
Factors effecting rate of reaction and why
Temperature, surface area, concentration of solution or pressure of gas, if catalyst is present
Ways to measure rate of reaction
Precipitate or change in colour
Change in mass(because of gas given off)
Volume of gas given off(using gas syringe)
What is meant by equilibrium
At some point reaction reaches equilibrium where the forward reaction and backwards reaction are at the same rate so concentration of each doesn’t change they are still reacting but overall concentration doesn’t change.
Only happens in a closed system where nothing comes in or out
How different factors affecting position of equilibrium (le Ch ateliers)
Concentration
If concentration of product is increased some product turns into reactants until it reaches equilibrium
What ever gets increased the equilibrium tries to decrease it
Temperature
One direction is endothermic the other direction is exothermic
So if temperature is changed the equilibrium changes into the direction to get the temperature back to what it was
e.g. temperature is increased so goes towards endothermic side
Pressure
Only effects reactions that include gases
If pressure is changed reaction try’s to counteract e.g. increase pressure reaction goes towards the side with least amount of gas molecules(moles) to try and get the pressure the same
Structure of Alkanes
For every carbon 2 hydrogen + 2 extra hydrogen
Structure of Alkenes
2 hydrogen for every carbon and a carbon to carbon double bond, Carbon can only make 4 bonds so if it has double bonds it will only be bonded to 1 carbon and 1 hydrogen
They are unsaturated because of the double bond
Why do alkenes have smoky flame
When not enough oxygen they undergo incomplete combustion producing carbon, carbon monoxide, carbon dioxide, water the smokiness being from carbon
What is a homologous series
Chemicals that have the same functional group so they react same way
What is hydrogenation
Alkene reacted with hydrogen in presence of catalyst to form a saturated alkane
What happens when halogen react with alkene and what can it be used for
Halogen react with alkene to unsaturated bond
Can be used as a test for Alkene
Bromine can be added and mixed starts colourless if alkene present reacts with is and becomes colourless if not present is cant react because all the other bonds are saturated
Describe addition polymerisation and how to draw it
Monomers containing double bonds join together in high pressure and catalyst to make a repeating chain polymer
Monomer is brackets with n on left
Polymer is brackets with bonds coming out and n in bottom left
Alcohol formular and structure
and properties
C(n) H(2n+1) OH same as alkanes but instead of a hydrogen on the right you have functional group OH
Properties flammable and completely combust. React with sodium to produce hydrogen
Oxidise with oxygen causing carboxylic acid(that’s why wine smells vinegary after sitting out)
Can dissolve stuff water cant so used in industry as solvents
Can also be used as fuel since it burns cleanly
Carboxylic acid names
methanolic acid, ethanoic acid, propanoic acid, butanoic acid
How do carboxylic acids react and what is the name of what they form
React like other acids so with a carbonate it produces water ,salt ,carbon dioxide
The salt produced will be something like sodium ethanoate, sodium butonate surname will end in onate
What are esters functional group and structure and how are they made
Functional group COO the functional group of the acid (COOH) the hydrogen get replaced by the alcohol
So a carboxylic acid and alcohol react to produce water and ester needs acid catalyst present
Its structure is a carboxylic acid on the left and acid on the right the OH of the acid and OH of the alcohol join together and get replaced by a single oxygen so the extra O and 2H form water
Carboxylic acid structure
Like a alkane but the last carbon doesn’t have any hydrogen attached but instead a oxygen double bonded and a OH bonded to it
Two types of condensation polymerisation
One can be made using two monomers each with 2 of the same functional group
Can also have one monomer with 2 different functional group
What is condensation polymerisation with reactants and how to show it
A diol (two alcohol functional group) and a dicarboxylic acid (two carboxylic acid) each with 2 of the same functional group react together
The reactants have one functional group on the left then a box with bonds(lines) going into a box then another functional group MIRRORED on the right. They each have an “n” in front
The polymer has the same functional group as an ester COO (because alcohol and acid reacting together) a box in between them and functional group mirrored on either side and another box on the far left with brackets and bonds going out “n” in the bottom left
Also has water produced for the same reason as the ester 2nH2O for every repeat of the polymer there is 2 water because there is 2 functional groups in every repeat of the polymer
Amino acid structure
amino group on left NH2 and carbon and hydrogen in middle with carboxylic acid functional group on right
How are proteins made
Amino acids join in condensation polymerisation the two functional group in the amino acid react together to produce one water and join to each other
Different gas tests
Chlorine should bleach damp litmus paper
Hydrogen squeaky pop test when burning hydrogen
Oxygen glowing splint should relight once in oxygen
CO2 bubble it through limewater and it should go cloudy
What is a Anion
Ion that gets attracted to anode so negative ion
So Carbonates, Sulphates and Halides
Carbonate test
Add substance to dilute acid then connect test tube to test tube of lime water to bubble the gas through if it turns cloudy then CO2 is present
Flame test
Can burn metals and look at their colour~
Lithium Crimson
Sodium yellow
Potassium lilac
Calcium orange-red
Copper green
Metal with NaOH test
Calcium white percipitate
Magnesium white
Aluminum white then back to clear
Copper Blue
Iron 2+ green
Iron 3+brown
Halide test
Add mixture to dilute nitric acid and add silver nitrate
The silver reacts with the halide to give a precipitate
Chlorine White (milk)
Bromine Cream (cream)
Iodine Yellow (butter)
What is a cation
Ion that is attracted to the cathode so positive ions
Sulphate test
Add HCL acid to get rid of any traces of carbonate then add Barium Chloride and a white precipitate will form if sulphate is present
Formulation
A precise mixture with a certain purpose
How has the atmosphere changed
Now it has 78% nitrogen 21% oxygen
First billion year volcanoes erupted giving out CO2, water vapour , small amount of nitrogen
Water vapour cooled and formed oceans, the CO2 dissolved in it and created precipitates causing sediments to form over time, animals used CO2 to make shells.
2.7 billion years ago algae evolved that used up carbon dioxide for photosynthesis and released oxygen decreasing amount of CO2 and increasing amount of Oxygen.
Over time more plants evolved increasing amount oxygen
How to tell if something is pure
The MP and BP will be a range and the boiling point will be higher than if it was pure and the melting point will be lower than if it was pure
What is the Rf value
How soluble the solute is in the solvent i.e. how far has the ink travelled compared to the solvent
So distance travelled by substance/ distance travelled by solute
Types of cracking and how to do them
Catalytic cracking vapoured long hydrocarbons passed over hot catalyst
Steam cracking vapoured long chain hydrocarbon mixed with steam at high temperature
Explain greenhouse effect
Sun gives out short wavelength radiation that goes through the atmosphere then gets absorbed by the earth and reflected back as long radiation, the long radiation then is absorbed by the greenhouse gases and re-radiated back trapping the long radiation and keeping the earth warm
Without it no life would exist but deforestation, agriculture, burning fossil fuels releases too many greenhouse gases
Effect of climate change
Extreme weather, melting glaciers causing rise in sea level, temperature change
Examples of air polution
Global dimming as a result of soot and other particulates that are formed because of incomplete combustion blocking out the sun
Carbon monoxide poisoning from incomplete combustion causing oxygen nit to be carried in the blood
Nitrogen oxides nitrogen and oxygen react in the heat of a engine during combustion causing nitrate oxide
Sulphur dioxide sulphur impurity’s in fossil fuels react with oxygen when fossil fuels are burnt
Acid rain caused by sulphur dioxide and nitrogen oxides reacting with rain water causing acid rain that corrodes building and kills plants
What is rust and what is needed to produce it
Iron + Oxygen+ water = hydrated iron oxide
Experiment to show rusting
3 test tubes
First one iron nail and boiled water(to remove any dissolved oxygen) with layer on oil on top so no oxygen gets in
Second one Iron nail with calcium chloride(to remove water) and stopper on top to stop moisture getting in so no water
Third one nail with water and air so there is both water and oxygen should be the only one that reacts
Why does aluminium corrode less than iron
Hydrated iron oxide flakes exposing more iron to the air while aluminium oxide doesn’t flake but stays on as a flat layer
Ways to prevent rusting
Paint
Electroplating
Greasing
all barriers to stop exposure to oxygen and water
Sacrificial method place more reactive metal like zinc close to it so that reacts rather than the iron
Galvanising is a mixture of both barrier and sacrificial method using zinc
Different ways to make potable water
Desalination Boil the sea water to form steam then condense the water to make pure water
Fresh water Filtration passed through a wire mesh and sand to filter out any solid bits then sterilisation where chlorine is added or uv light is used
Reverse osmosis Water is forced through a semi-permeable membrane which only allows water through
How is waste water treated
First screened to remove any large objects
Then let to settle in a sedimentation tank where there is effluent on top and sludge on the bottom
The sludge is taken away to be digested by anaerobic bacteria to digest releasing bio gas that is used as fuel and the rest of the sludge as fertiliser
The effluent in top has air bubbled through so there is oxygen for aerobic bacteria to digest the harmful microbes and other organic material the water is then released back into the environment
Formular for ammonia
NH3
Describe harbour process
Nitrogen and hydrogen added in ratio 1:3 heated at high pressure over catalyst to make ammonia not all the hydrogen and nitrogen react so the gases leaving are cooled so ammonia condenses and is taken away while the gases are recycled back
