More organic chemistry TRIPLE ONLYYY DONT USE IF UR NOT TRIPLE WONT HELP U Flashcards
properties of alkenes
- have the same general formula
- differ by CH2 in molecular formulae from neighbouring compounds
- show a gradual variation in physical properties, such as their boiling points
what is the general formula for alkenes
CnH2n
first 3 alkenes
ethene
propene
butene
alkenes are unsaturated, what does this mean
they have a double carbon bond
what is a functional group
an atom, or a group of atoms, which determine the main chemical properties of an organic compound
what happens when we combust alkenes
the products are water, carbon dioxide and unburnt carbon particles, because of incomplete combustion
- alkenes burn in air with a smoky flame
what is hydrogenation
reacting an alkene with hydrogen
what happens during hydrogenation
- two hydrogen molecules add across the double bond
- double carbon to carbon bond converted into single
- an alkane is produced
how would we increase the yield of ethanol in a reversible reaction
pass back unreacted ethene and steam back through the catalyst
properties of hydration reactions
- water must be in the form of steam
- phosphoric acid used as a catalyst
- temperature at 300 degrees, pressure at 70 atmospheres
- forms alcohols
- reversible reaction
properties of alkenes reactions with halogens
- halogen molecules are added across the double bond
- double carbon bond turns into single
uses of alcohols
- fuels
- solvents
- alcoholic drinks
how to test for alkanes or alkenes
- bromine water test
- there is no change when an alkane is mixed with bromine water
- bromine water goes colourless when mixed with an alkene
how can we make ethanol
by reacting ethene with water
- using fermentation
what is an advantage of hydrating ethene
the reaction produces a high yield of ethanol
disadvantages of hydrating ethene
- high temperature meaning lots of energy
- ethene from the reaction comes from crude oil which is not renewable
how does fermentation work
- Start with a sugar solution such as glucose
- Mix it with yeast
- The yeast converts the sugar solution to a solution of ethanol, carbin dioxide gas is also produced
what are the conditions needed for fermentation
30 degrees
- reaction must take place in anaerobic settings (without oxygen)
advantages of fermentation
- low temperature means the reaction does not require a lot of energy
- sugar from the reaction comes from plants and is therefore renewable
.disadvantage of fermentation
the product is an aqueous solution of ethanol, meaning we need to purify the ethanol by distillation, which requires energy
describe alcohols solubility in water
they are soluble in water and form neutral solutions
as the number of carbon molecules in an alcohol increases…
the solubility decreases
what are the products when sodium reacts with an alcohol
an oxide and hydrogen gas
- eg sodium ethoideplus hydrogen
what is an oxidising agent
a substance that can oxidise other substances in a chemical reaction
what are the products when alcohols react with oxidising agents
carboxylic acid and water
what are the features of the combustion of alcohols
alcohols release energy when combusted
- combusting an alcohol in air produces carbon dioxide and water
features of carboxylic acid in water
- they are weak acids in water
- ## reversible reaction
what is a weak acid
an acid that only partially dissociates into it’s H+ ions when dissolved in water
features of carboxylic acids reacting with metal carbonates
- an “oate” is made, for example, an ethanoate (for ethanol), propanoate (for propanol)
- carbon dioxide is produced
- water is produced
features of reacting a carboxylic acid with an alcohol
- an ester is formed
- water is formed
why are esters useful
they have a nice smell, often used iun foods and perfumes
what catalyst is used for the reaction between ethanol and ethanoic acid
sulfuric acid
what is a polymer
a chain of repeating units of monomers
features of addition polymers
- the monomers are alkene
- the monomer has a double carbon bond, but the polymer has a single
- the name of the polymer is “poly” followed by the name of the monomer
- the repeating units have the same atoms as the monomer
why, in addition polymers, do the repeating units have the same atoms as monomers
no other molecules are formed in the reaction
features of condensation polymers
- monomers are not alkene
- when these monomers react, we lose small molecules such as water
how are condensation polymers formed
- start with two different monomers
- each monomer has two of the same functional group
- To form the condensation polymer, we react out two monomers together
- We can now continue to add monomers to either end, allowing us to produce a long polymer
what is a polyester
a type of polymer where thousands of monomers join together to form it
key features of amino acids molecules
- they have two different functional groups
- amine group
- carboxyllic acid group
what do glycine molecules join together to form
to form polypeptide
why is the polymer called polypeptide
because it’s made from only one type of amino acid
what are proteins
naturally occurring polymers of amino acids
what does DNA do
encodes genetic instructions that living organisms need to develop and function
what does DNA consist of
two polymer chains made from monomers called nucleotides, in the form of a double helix
examples of naturally occurring polymers
- protein
- starch
- cellulose
properties of hydrogenation
- 150 degrees
- nickel catalyst
what is a homologous series
molecules with the same functional group
alcohol functional group
OH
example of an oxidising agent
acidified potassium dichotomate
carboxyllic acid functional group
COOH
when does a polymer become a protein
when we combine different amino acids into the same chain
where is dna found
in almost all living organisms including animals plants fungi bacteria
