Flashcards in Organic Deck (66):
what is cracking?
Breaking long chain alkanes into smaller hydrocarbons
High temperature 1000°C
high-pressure 70 atm
Produces a lot of alkenes
high temperature 450°C
mostly aromatic hydrocarbons and motor fuels produced
What do you get when you burn alkanes in plenty of oxygen?
Carbon dioxide and water
Products of incomplete combustion
Carbon monoxide or carbon particles (soot)
How is carbon monoxide poisonous?
It binds to the same sites on haemoglobin molecules in the red blood cells as oxygen molecules. So oxygen can’t be carried around the body
How is carbon monoxide removed from exhaust gases
What is the greenhouse effect
Greenhouse gases in our atmosphere absorb infrared heat and emit some of the energy back towards earth keeping it warm
How does nitrogen oxides pollute the air
Hydrocarbons and nitrogen oxides reacts in the presence of sunlight to form ground level ozone which makes up smog.
How does sulphur dioxide gas pollute the atmosphere
It dissolves in moisture and is converted into sulphuric acid which causes acid rain destroys trees and vegetation and corrodes buildings and statues and kills fish in lakes
How is sulphur dioxide removed from power stations fluegases
Powdered calcium carbonate or calcium oxide is mixed with water = alkaline slurry
acidic sulphur dioxide gas reacts with the calcium compounds to make harmless calcium sulphate
What are the conditions for free radical substitution
How does the Ozone protect us
Absorbs ultraviolet radiation from the Sun stopping it reaching us
Can cause sunburn or even skin cancer
What are the conditions for elimination
Warm dissolved in ethanol
Test for alkenes
Bromine water goes from Orange to colourless
What’s a polymer
Long chain molecules formed from monomers joined together
How do you make ethene from ethanol
Heat with a concentrated sulphuric acid catalyst
To produce ethene and water
Hydration of ethene by steam conditions
Solid phosphoric (V) acid catalyst
Fermentation of glucose
Yeast in anaerobic conditions
produces ethanol and carbon dioxide
Optimum temperature 30 to 40°C
What is a biofuel
Fuel that’s made from biological material that’s recently died
Oxidising alcohols (Reagent and Method for primary alcohols)
Oxidise using potassium dichromate acidified with sulphuric acid
Distil to get aldehyde
reflux to get carboxylic acid
Oxidation of alcohols results
Primary alcohols oxidised to aldehydes and then to carboxylic acids
secondary alcohols oxidised ketones
Tertiary alcohols aren’t oxidised
Tests to distinguish between aldehydes and ketones
-aldehyde blue to brick red precipitate
-Aldehyde Silver mirror
Test tube reaction for primary, secondary and tertiary alcohols
Warm with acidified potassium dichromate
Primary orange solution turns green
Secondary orange solution turns green
How to do tollens reagent
Silver nitrate solution
dilute sodium hydroxide solution light brown precipitate
dilute ammonia solution until precipitate dissolve completely
Test for carboxylic acids
solution begins to fizz if positive
bubble gas through limewater
if CO2 limewater turns cloudy
What are high resolution mass spectrometers
Measure atomic and molecular masses extremely accurately
What is infrared spectroscopy
Beam of IR radiation is passed through sample of a chemical
Absorbed by covalent bonds increasing their vibrational energy
bonds between different atoms absorb different frequencies of IR radiation
What is the fingerprint region
500 to 1500
Unique to particular compound
What is racemate
Contains equal quantities of each enantiomer of an optically active compound
no optical activity
Common reducing agent
NaBH4 dissolved in water with methanol
How to make esters
Heat a carboxylic acid with an alcohol in the presence of a strong acid catalyst. Usually hydrochloric acid
Uses of esters
Flavourings for food industry
Good solvents in glues and printing inks
Plasticises to make plastic more flexible
Acid Hydrolysis of esters Conditions
Reflux with dilute acid such as hydrochloric or sulphuric
Base hydrolysis of esters conditions
Reflux with alkali such as sodium hydroxide
How to convert vegetable oils into biodiesel
React with methanol using potassium hydroxide as a catalyst
Why is ethanoic anhydride used in industry to make aspirin
Cheaper than ethanoyl chloride
safer to use as less corrosive and doesn’t produce dangerous hydrogen chloride fumes
Common drying agent
How to get nitrobenzene
Warm benzene with concentrated nitric and sulphuric acid
How to make nitrobenzene. Including equations of electrophile generation
Warm benzene with concentrated nitric or sulphuric acid
Sulphuric acid axis catalyst to make nitronium ion NO2 + Which is the electrophile
HNO3 +H2SO4 -> H2NO3+ + HSO4-
H2NO3+ -> NO2+ +H2O
How do quaternary ammonium salts act as cationic surfactants?
The long hydrocarbon tail will bind to nonpolar substances such as grease whilst the cat ionic head will dissolve in water
Why are Quaternary ammonium salts used often in fabric conditioners?
The positively charged ammonium ion will bind to negatively charged surfaces such as hair and fibre getting rid of static
Why are a means with benzene rings the weakest bases?
The benzene ring draws electrons towards itself and the nitrogen lone pair get partially delocalised onto the ring so the electron density on the nitrogen decreases making the lone pair less available
Why are amines with alkyl groups stronger bases?
The alkyl groups push electrons on to attached groups so the electron density on the nitrogen atom increases making the lone pair more available
How do you make an amine from a halogenoalkane?
Heat with excess ammonia
What do you use to make a nitrile into a primary amine?
Use lithium aluminium hydride (LiAlH4) in a non-aqueous solvent (such as dry ether) followed by some die loot acid
How are primary amines made from nitriles in industry?
Nitriles are reduced using hydrogen gas with a metal catalyst such as platinum or nickel at high temperature and pressure (catalytic hydrogenation)
How do you turn nitrobenzene into an aromatic amine?
Heat nitrobenzene with tin metal and concentrated hydrochloric acid reflux to make a salt
add sodium hydroxide solution
What are Polyamides made up of?
Dicarboxylic acids and diamines
Form amine links
What make up polyesters?
Dicarboxylic acids and diols
Form Ester links
How do you reverse condensation polymerisation?
Why are condensation polymers generally stronger and more rigid than addition polymers?
They are made up of chains containing polar bonds so have permanent dipole dipole forces and hydrogen bonds as well as van der Waals
What makes Polyalkanes non biodegradable?
They are made up of nonpolar carbon chains which makes them unreactive and chemically inert
What is a zwitterion?
And ion that has both negative and positive charge in different parts of the molecule
Thin-layer chromatography method To separate amino acid’s
Draw pencil line near the bottom of chromatography plate and put concentrated spot of mixture of amino acids
Dip the bottom of the plate into solvent
Once the solvents nearly reached the top take the plate out and mark the solvent front with a pencil
Either spray ninhydrin solution on the plate to turn the spots purple or use special plate that has fluorescent dye so it glows when UV light shines on it
Work out Rf values
Why can amino acids be separated and identified using thin-layer chromatography?
They have different R groups so will all have different solubilities in the same solvent
How do you work out Rf values?
Distance travelled by spot/Distance travelled by solvent
What are proteins?
Condensation polymers of amino acids joined together by peptide links
What does the chiral centre of an enzyme called the active site to be?
Stereospecific so they only work on one enantiomer of the substrate
What is cisplatin?
A complex of platinum with two chloride ion ligands and two ammonia ligands in a square planar shape
its used as an anti cancer drug
How does cisplatin treat cancer?
Binds to the DNA causing kinks in the helix which stop proteins that replicate it from copying it properly stopping tumour cells reproducing
Describe in detail how cisplatin causes kinks in the DNA helix?
The nitrogen atom on a guanine base forms a coordinate bond with cisplatins platinum ion, replacing one of the chloride ions.(ligands substitution)
A second nitrogen atom from another guanine replaces the second chloride ion
The cisplatin bounded causes a kink so the DNA strands can’t unwind and be replicated
What is the standard substance in NMR spectroscopy And why is it used?
It has 12 hydrogen atoms all in identical environments so produces a single absorption keep well away from other absorption peaks
It is inert (so won’t react with the sample),non-toxic and volatile (so easy to remove)
What are the solvents for proton NMR
Thin layer chromatography method
Stationary phase is thin-layer of silica or alumina fixed to a glass or metal plate
Draw pencil line at bottom (baseline) And spots of mixtures
mobile phase Allow to dry and place in beaker
Leave till solvent near top and Mark solvent front
Leave to dry