organic chem Flashcards
what is hydrocarbon
compound made of only hydrogen and carbon atoms
alkanes vs alkenes
alkanes have all c-c single bonds
alkenes have a double bone between two of the carbon atoms
alkane general formula
C n H 2n+2
what is a homologous series
group of organic compounds that react in a similar way to
why are alkanes suturated
each carbon atom forms 4 single covalent bonds
first four alkanes
methane
ethane
propane
butane
what happens if chain is longer
more intermolecular forces therefore:
• more viscous
• less flammable
• high boiling point
what are the waste products of complete compustion
co2 + h2o
complete combustion equation
hydrocarbon + oxygen —> co2 + h2o
what order do you balance complete combustion
c, h, o
what is crude oil and how do they form
a fossil fuel formed from the remains of dead plants & animals buried in mud
high temp and pressure turn remains to crude oil, drilld from rocks to obtain
are crude oils renewable
no
what is fractional distillation
separates all the different hydrocarbons (mostly alkanes) in crude oil
order of what gets condensed first in fractioning column
HDKPL
hellish devils kill petty liars
Heavy fuel oil
Diesel oil
Kerosene
Petrol
LPG
how does fractional distillation work
• oil is heated and vaporised
• vapour enters fractioning columm
• column has temperature gradient
• longer HC have high BP, condense at bottom
• shorter HC have low BP, condense later on at top, just below BP
• each fraction had mixture of HC with similar numbers of BP & carbon atoms
two uses of crude oil
fuel
to make new compounds for things like polymers, lubricants
what is cracking
splitting long chain hydrocarbons
why is cracking necessary
• shorter HC are flammable so are fuel
• longer HC are thick like tar, not useful
• products can be useful fuels
cracking method
• cracking is thermal decomposition so is heated and vapourised
• vapour passed over hot powdered aluminium catalyst
• catalytic cracking: LC molecules split on surface of catalyst
• steam cracking: vapourise, mix w steam, heat.
products of cracking
(long chain hydrocarbon —>)
shorter hydrocarbon + alkene
why are alkenes more reactive than alkanes
their double bonds can open up and bond with other atoms
alkene general formula
C n H 2n
what else is produces when alkenes combust (other than co2 and h2o)
carbon and carbon monoxide
C and CO
how does incomplete combustion burn
smoky yellow flame
what is a functional group
group of atoms that determines what molecule is and how it reacts
two reactions of alkene reactions basic descriptions
addition: double opens for a new atom
hydrogenation: hydrogen reacts and forms alkane in presence if catalyst
how can you test for alkenes
add bromine
• when orange bromine water is added, bromine has addition reaction to alkene
• turns colourless
what is the name of the product of halogen and alkene reactions
di(first syllable)oethane
what happens when alkenes react with steam/water
alcohol is formed
e.g ethanol ch3ch2oh
what do you name alcohols
(prefix)ol
what is a polymer
small molecules called monomers join to form long chain molecules
name of product when single ethenes join together
poly(ethene)
to remember when drawing polymers
c-c bonds continue into bracket
n is put to show continuation
carboxylic acid functional group
cooh
name for products of carboxylic acids
(prefix)anoic acid
equation and example of carboxylic acid
ethanoic acid + sodium carbonate
acid + carbonate -> salt + water + co2
ethanoic acid + sodium carbonate -> sodium ethanoate + water + co2
ester functional group
coo
what forms esters
alcohol + carboxylic acid
cooh
o = c - oh
example of ester equation (ethane)
ethanoic acid + ethanol -> ethyl ethanoate + water
ethyl ethanoate
= o
c (h3) - c -o - c (h2) - c (h3)
what is condensation polymerisation
polymerisation involving monomers from different functional groups
what happens as new bonds form in condensation polymerisation
a small molecule (h2o) is lost
ethan example of condensation polymerisation
remember + 2nH2O at end of
what is the amino group and what functionl groups does it contain
amino acid group: nh2
carboxyl group: -cooh
what are polypeptides and what happens when they are a long chain
polymers formed by amino acids
long chains known as proteins
three examples of naturally occuring polymers
amino acids
proteins
dna molecules
what are dna molecules made from
nucleotide polymers
