7-Organic Chemistry Flashcards
What is a hydrocarbon
A compound formed form carbon and hydrogen atoms only
What bonds do alkanes have
C-C single bonds
What r the first four alkanes
Methane,
Ethane,
Propane,
Butane
What is the general formula for alkanes
C H
n 2n+2
What does it mean that alkanes are saturated
Each carbon atom forms four single covalent bonds
What are the properties of shorter hydrocarbons
More runny- less viscous,
Lower boiling points,
The more flammable it is,
What is the equation for the complete combustion of any hydrocarbon
Hydrocarbon + oxygen —> carbon dioxide + water (+energy)
What is crude oil
A mixture of lots of different length hydrocarbons
How does fractional distillation work
The oil is heated up until it is a gas, it goes into the fractioning column. It is hotter at the bottom and colder at the top. The longer hydrocarbons have high boiling points and are condensed into liquids and drain out lower in the column. The shorter hydrocarbons have lower boiling points and condense nearer the top.
The crude oil is now separated into different fractions
What is a fraction
Separated during fractional distillation, it is a mixture of hydrocarbons that all have similar boiling points and a similar number of carbon atoms
What are the uses for oil
Provides the fuel for cars, trains, planes.
The petrochemical industry uses some hydrocarbons as a feedstock to make new compounds for things like: polymers, solvents, lubricants and detergents
What is cracking
Splitting up long-chain hydrocarbons to make shorter ones
What r the different methods of cracking
Catalyst cracking,
Steam cracking
How does catalyst cracking work
Heat the long hydrocarbons to vaporise them,
Pass the vapour over hot powdered aluminium oxide,
The long hydrocarbons are split apart on the surface of the specks of catalyst
How does steam cracking work
The long hydrocarbons are heated up and vaporised.
Mix them with steam
Heat to a very high temperature
What is an alkene
A hydrocarbon which has a double bond between two carbons in its chain
What are the first 4 alkenes
Ethene
Propene
Butene
Pentene
What is the general formula for an alkene
C H
n 2n
What is produced in complete combustion of alkenes
Water + Carbon dioxide
What is the equation for incomplete combustion of alkenes
Alkene+ oxygen—-> carbon + carbon monoxide + carbon dioxide + water (+energy)
Why is there usually incomplete combustion of alkenes
Because there isn’t enough oxygen in air for complete combustion
What type of flame is produced in incomplete combustion
Smokey yellow flame
What is the addition of hydrogen to an alkene called
Hydrogenation
What is added to an alkene to make alcohol
Steam
What is an industrial method of producing ethanol
Mixing ethene with steam and then passing it over a catalyst
What is a test for alkenes
Bromine is added to the compound, if it is an alkene the solution will turn from bright orange to colourless.
If it is a saturated compound, like an alkane, the solution will stay bright orange
What is a polymer
A long chain of repeating monomers
What is polymerisation
Monomers joining together
What bonds do the monomers have in addition polymerisation
Double bonds which then split up to bond with the next monomer
What is the functional group of alcohols
OH
What is the general formula for alcohols
C H OH
n 2n+1
What r the first four alcohols
Methanol
Ethanol
Propanol
Butanol
What do all the names of the alcohols end in
ol
Eg. Ethanol
How is the formula for an alcohol shown
Needs to show the OH functional group
eg. CH4O would be CH3OH
What are the properties of alcohols
They are flammable,
Neutral pH,
Most are soluble in water
What r the products for complete combustion of alcohols
Carbon dioxide and water
What is produced when an alcohol reacts with oxygen
A carboxylic acid
Why are alcohols like methanol and ethanol uses as solvents
They dissolve most things that water can, but they can also dissolve substances water can’t. eg. hydrocarbons, oils and fats
Why are the first 4 alcohols used for fuels
They burn fairly cleanly and are non-smelly
What is fermentation
An enzyme in yeast coverts sugars into ethanol
What is the equation for fermentation
Sugar ——> ethanol + carbon dioxide
What conditions does fermentation work best at
Around 37`C
Slightly acidic solution
Anaerobic conditions (no oxygen)
What is the functional group of carboxylic acids
COOH
What do all carboxylic acid names end in
anoic
eg.methanoic, ethanoic
What are the names of the first four carboxylic acids
Methanoic acid,
Ethanoic acid
Propanoic acid
Butanoic acid
When a carboxylic acid reacts with a carbonate what does the salt name end in
anoate
eg. Methanoic acid will produce methanoate
Why are carboxylic acids weak acids
Because they don’t fully ionise in water (not all the acid molecules release their H+)
What is the the functional group of an Ester
COO
What is the equation for an Ester
Alcohol + carboxylic acid ——> Ester + water
In an acid catalyst like concentrated sulphuric acid
What does condensation polymerisation involve
Monomers with different functional groups
What is lost with each new bond in condensation polymerisation
A small molecule like water
What do the boxes within formulas represent
The carbon chain
What two functional groups are in amino acids
Amino group (NH2) Carboxyl group (COOH)
What is an example of an amino acid
Glycine
What can amino acids form via condensation polymerisation
Polymers known as polypeptides
What are one or more long chains of polypeptides known as
Proteins
What are the two polymer chains in DNA called
Nucleotides
What are the four different bases in the nucleotides
A, T, G, C
What are cross links
They pair up the bases from the two nucleotides and keep them together to give the double helix structure
What larger polymers can sugars react together to make
Carbohydrate polymers
eg. Starch and cellulose
