organic chemistry Flashcards
how are condensation polymers made
using ester links
what do carbons mostly bond to
hydrogen and carbon themselves
what are the first 4 alkanes
methane
ethane
propane
butane
what is the meaning of homologous series and give an example
groups of organic compounds/molecules that react in a similar way and have similar chemical properties
Same functional group / same general formula / differ by CH2
eg alkanes
formula for alkanes
CnH2n+2
why do we refer to alkanes as saturated
no double bonds- every carbon atom has 4 single covalent bonds and are all bonded to something
what is a hydrocarbon
A hydrocarbon is a molecule that only contains the elements carbon and hydrogen hydrogen.
What are trends of alkanes as you go down the group
boiling point increases
volatility decrease
viscosity increases
flammability decreases
what is the equation for complete combustion
hydrocarbon+oxygen> carbon dioxide+water
why do we say complete combustion is an exothermic reaction
it releases a lot of energy
what is being oxidised in complete combustion
carbon and hydrogen
what is crude oil
a fossil fuel found deep underground with mainly hydrocarbons(mainly alkanes)
how is crude oil formed
Crude oil is formed from the remains of dead plants and animals, particularly plankton.
These organic remains were covered by mud and sand, and buried in the earth.
Over millions of years, these organic remains were compressed under a lot of heat and pressure.
The heat and pressure chemically changed the organic remains into crude oil
what is fractional distillation
heating and seperate different compunds
what are the steps of fractional distillation
feed oil into chamber and heat it until most oil has turned into gas
pass gaseous mixture into fractionating column(which is hot at the bottom and cools down at top)
when the hot gases reach a region that is cooler than their boiling point they condense into a liquid
what happens to short chain hydrocarbons vs long in fractional distillation
long-quickly condense back into liquid and drain out right away(eg bitumen/heavy fuel oil and can be seperated further into heating oil/fuel oil)
short-rise up much more(diesel/petrol and kerosene
very short- stay as gas entire time(lpg)
why are the shorter chain hc better fuels
they are more flammable
what is a feedstock
A feedstock is a raw material used to provide reactants for an industrial reaction.
what is a petrochemical
A petrochemical is a substance made from crude oil, via chemical reactions.
what is the relation between feedstocks and petrochemicals
So basically, the different hydrocarbons in crude oil are all feedstocks, but the useful things we then make from those hydrocarbons (polymers, solvents, lubricants, detergents etc.), are all petrochemicals.
what is cracking
a thermal decompostion reaction where longer less useful hc are broken down into shorter more useful/flammable hc
what are the 2 methods of cracking
catalytic and steam cracking
what are the steps in catalytic cracking
heat long chain hydrocarbons and vapourise them
use hot powdered aluminium oxide as catalyst passing vapour over powder splitting them apart into 2 smaller hc
what are the steps of steam cracking
heat and vapourise hydrocarbons to
mix them with steam
heat them to very high temps causing them to split
what is the difference between alkenes and alkanes
allkenes unsaturated -have double bond
making them more reactive than alkanes
react with bromine water changing it from orange to colourless
form polymers
alkene addition reaction with hydrogen
alkene+hydrogen gas>alkane
+catalyst
addition reaction with water
alkene+water(steam/vapour)>alcohol
+catalyst and high temps
alkene+halogen=
alkene+halogen>dibromo-alkane
how do we name addition polymers
put “poly” in front of monomer
what do addition polymerisation reactions require
high pressure and catalysts to work
what makes alcohols different to alkanes
an oh functional group
what is the general formula for alcohol
CnH2n+1
what are the properties of the 1st 4 alcohols
flammable
soluble
oxidise to form carboxylic acids
alcohol+oxygen
=co2 + water
uses of alcohols
can be used as fuels(release a lot of energy)
as solvents in industry (can dissolve fats and oils that water cant)
what are the uses of ethanol
As a chemical feedstock to produce other organic compounds.
As a biofuel (ethanol can be burned like petrol).
Used in alcoholics drinks such as beer, wine, and spirits
what is a comercial way ethanol is produced/pros and cons/conditions
ethene+steam
high temp/catalyst/high pressure
(300 degrees)/phosphoric acid/60-70 atm
this reaction is cheap and efficient
ethene is finite/will become expensive if used up
what is another way to produce ethanol/pros and cons/conditions
fermentation(anaerobic respiration of sugars by yeast cells to produce ethanol and c02
must be in fermentation tanks at temp of 30-40 and must be anaerobic so ethanol isnt oxidised to ethanoic acid
glucose is renewable and yeast is easy to grow
process is slow and ethanol made isnt purre so must be further purified/ distilled in fractional distillation
what is the functional group of carboxylic acids(homologous series)
cooh/names all end in -anoic acid
are carboxylic acids strong or weak
weak
what are the - ions that carboxylic acids form
anoate
carboxylic acid +metal carbonate
water, salt and carbon dioxide
how are carboxylic acids made
taking an alcohol and oxidising it with an oxidising agent
carboxylic acids reaction with metal/metal hydroxide
Carboxylic acid + metal ➔ salt + hydrogen
Carboxylic acid + metal oxide ➔ salt + water
Carboxylic acid + metal hydroxide ➔ salt + water
what is the functional group of esters
coo in the middle
what are properties of esters
volatile
nice/fruit smelling
how do we make esters
carboxylic acids+alcohol>ester+water
(acid catalyst)(sulfuric acid)
what is the only ester you need to know how to form
Ethanoic acid + ethanol ➔ Ethyl ethanoate
how are polyesters made
with dicarboxylic acid monomers(2 carboxylic acid groups) + diol monomers(2 alcohol groups)
what is given up when making condensation polymers
dicarboxylic acid monomer gives up oh group and diol gives up h forming a water molecule
this leaves carbon from dicarboxylic acids carbon to react with the oxygen of the diol monomer
the ester link
for molecules to combine in condensation polymers what is required
each monomer must have at least 2 functional groups
must be 2 different functional groups overall
must be a small molecule given off
what do the boxes in the middle of the monomers represent
the rest of the molecule in simplified form
what is a dimer
2 monomers combined
When is a polymer referred to as a ‘condensation’ polymer?
When water is a produced as a by-product of the reaction
what types of polymers are biodegradable and why
condensation as ester links can be broken down by microorganisms
what groups do all amino acids have
carboxyl group and amino group(h-n-h)
how do amino acids join to form polymers
through condensation reactions when bottom right oh from carboxyl group and bottom left h from amino group react producing water and allowing carbon and nitrogen to bond together(called amide bond/peptide bond)
what are the monomers in dna
structures called nucleotides which contain bases(t a g c) -basically 4 types
what are genes
these nucleotides arranged in different orders
how/why does the double helix structure form
the 2 polymer chains link together coiling naturally to keep the genes intact and prevent damage
what are the elements that make up carbs
carbon,oxygen and hydrogen
what are carb polymers and what are they called
polyssacharides like starch,cellulose and
glycogen
what is the general meaning of carbs
number of polymers and monomers we derive energy from
what are the monomers of carbs called
monosaccharides like glucose or fructose
what monomers combine to form a polypeptide
amino acids
What do polypeptides form once they fold up?
protein
