organic Flashcards
do alkanes or alkenes have a double bond
alkenes
general formula of alkenes
CnH2n
which type of hydro carbon is unsaturated and why
alkenes because of the double bond. This bond also makes them more reactive
are alkanes saturated or unsaturated
saturated
how to remember if rules about hydro carbons
alkenes are unsaturated because of their double bond - They have bonds that could be use in other places so they are “unsaturated”
what is the empirical formula
simplest whole number ratio of atoms of each element in a compound
what is a homologous series
group of compounds that can all be represented by the same general formula
what is the functional group for alkenes
C=C
what is the functional groups for alcohols
O-H
what is the functional group for carboxylic acids
C=OOH
what is the functional group for esters
c=oo
what is an isomer
same molecular formula but atoms are arranged differently or same number of protons different number of neutrons
how is crude oil split up
The oil is heated until it is a gas. They then enter a fractionating column, which is hotter at the bottom and cooler at the top. When they reach the part of the column that is lower than their boiling point they condense and drain out of the column. Shorter chain hydro carbons have lower boiling points. Bubble caps stop the liquids from running back down the column
properties of long chain hydrocarbons
high poling points and viscous (thick and gloopy)
why are long chain hydro carbons split
short chain hydro carbons are in higher demand so they are split into shorter chain hydro carbons
what type of reaction is cracking
thermal decomposition - breaking down molecules into smaller ones by heating
what does cracking produce
alkenes
what are the conditions for cracking
vaporized hydro carbons are passes over a powdered catalyst at about 600-700 degrees. Silica or alumina are used as a catalyst.
complete combustion equation
hydrocarbon+oxygen->carbon dioxide + water
what is incomplete combustion
It happens when there is not enough oxygen, as well as carbon dioxide and water it produces carbon monoxide - toxic gas and carbon in form of soot
why is carbon monoxide dangerous
it binds with haemoglobin to stop red blood cells carrying oxygen around the body = fainting, coma or death
what is acid rain caused by
sulfur dioxide and nitrogen oxides
what does sulfur dioxide come from
sulfur impurities in hydrocarbon fuels
how are nitrogen oxides made
when the temperature is high enough for nitrogen and oxygen in the air to react e.g. in car engines
what happens when sulfur dioxide and nitrogen oxides mix with water vapour in clouds
they form dilute sulfuric acid and nitric acid = acid rain
what happens when halogens and alkanes react
they form haloalkanes. A hydrogen atom is substituted with a halogen = substitution reaction.
what happens when halogens react with alkenes
they form haloalkanes. This is an addition reaction because the c-c double bond is split open and the halogens are added on.
how do you test for alkene
shake with orange bromine water and it will go colourless
what is the general formula for alcohols
CnH2n+1OH
what the is alcohols functional group
OH
what happens when alcohols are oxidized
they form carboxylic acids
what is an oxidizing agent used to turn alcohol to carboxylic acids
potassium dichromate (VI) in dilute sulfuric acid
when is microbial oxidization
when some organisms use alcohols as an energy source, they use oxygen in the air to oxidize alcohols.
what happens when alcohols are burnt
they are oxidised
how is ethanol produced by ethene and steam
Ethene reacts with steam to make ethanol. This is an addition reaction because water is added to the molecule. The reaction needs a temp of 300 degrees and 60-70 atmospheres. Phosphoric acid is used as a catalyst.
pros of cons of ethene + steam
cheap , crude oil is non- renewable
how is ethanol made by fermentation
sugar is converted into ethanol using yeast. Yeast cells contain an enzyme. The mixture need to be at 30 degrees and have anaerobic conditions as other wise the ethanol would turn into ethanoic acid.
pros and cons of fermentation
renewable resources, ethanol isn’t very concentrated and needs to be distilled and purified.
what is the carboxylic acid functional group
COOH
what do carboxylic acids produce when reacting with metal carbonates
salt, water , carbon dioxide
what do carboxylic acids produce when reacting with metals
salt and hydrogen
how is vinegar made
ethanoic acid is dissolved in water to make vinegar
what is the ester functional group
COO
how are esters formed
alcohol and a carboxylic acid
an acid catalyst is used e.g. concentrated sulfuric acid
how do you make esters in the lab
add a few drops of concentrated sulfuric acid to a boiling tube using a dropping pipette, add 10 drops of ethanoic acid, add an equal volume of ethanol. Place the beaker in a beaker of water and place on a tri pod. Use a Bunsen burner till the water starts to boil, then turn it off. After 1 minute remove the tube and allow it it cool. Then pour the mixture into a test tube of sodium carbonate solution and mix. A layer of the ester should form on top of the solution.
why are esters useful
used in perfumes and food flavourings
what are addition polymers made from
un saturated monomers
how do you draw the repeat unit of a polymer
why are polymers hard to dispose of
addition polymers are inert - the c-c bonds are strong, they take ages to bio degrade and burning produces toxic gases
what are polyesters
condenstation polymers
what are biodegradable polyesters known as and why
biopolyesters- they are broken down by bacteria and other living organisms in the environment
