Organic chemistry (paper2) Flashcards
Name 4 products made from crude oil
Plastics, petrol , cosmetics and pharmaceuticals
Where do we find crude oil?
In rocks
Is crude oil finite or non-finite
Finite
How is crude oil formed?
Over millions of years from the remains of tiny sea creatures called plankton which were buried in mud
What is crude oil
A mixture of molecules called hydrocarbons
What is methane made up of?
One carbon atom covalently bonded to 4 hydrogen atoms
What are hydrocarbons?
Molecules made up of hydrogens and carbons only
Why are alkanes saturated?
Carbon atoms are fully bonded to hydrogen atoms(max amount of hydrogens as their can be)
Name the first four alkanes in order
.methane (one carbon atom)
.Ethane (2)
.Propane(3)
.Butane(4)
What is viscosity?
Viscosity is the thickness of the fluid (the higher the thicker)
What happens to the viscosity of the hydrocarbon molecule as they get bigger
.They get more viscous(they flow slowly)
What is flammability?
How easily a substance combusts
What happens to the flammability as the size of the hydrocarbon increases
.Flammability decreases
What hydrocarbon molecule is used in Bunsen
burners?
Methane
What is boiling point?
The temperature at which a liquid turns into a gas
What happens to the boiling points as the hydrocarbons get bigger
Boiling point increases
Are methane, ethane, propane and butane gases at room temperature? if so why?
Yes, because they have a boiling point lower than room temperature
Name three items which run on hydrocarbon fuels?
Ships cars and planes
What do hydrocarbon fuels release when combusted?
Energy
What happens if the oxygen is unlimited?
The reaction produces carbon dioxide and water (this is called complete combustion)
What is the equation for alkanes
C(N)H(2n+2)
Name the general formulae for a complete combustion reaction of a hydrocarbon
Hydrocarbon + oxygen gives carbon dioxide + water (+energy)
Balance this (C3H8+02 gives CO2 plus H20)
C3H8+502 gives 3CO2 + 4H20
What do we need to do to the hydrocarbons in crude oil in order for them to be useful?
Separate them via a technique called fractional distillation
Where does fractional distillation usually take place?
In huge fractionating columns which we usually find in oil refineries
Explain all the steps of the fractional distillation of crude oil
.First we heat the crude oil to a very high temperature causing it to boil,
All the hydrocarbons evaporate and turn into a gas
.Crude oil vapour is now fed to the fractional distillation column, column is hotter at the bottom and cooler at the top
.The hydrocarbon vapours rise up the column and condense once they reach their boiling point
.The liquid fractions are then removed
.The remaining hydrocarbons then move up the column and condense once they reach their boiling point
. Very long chain hydrocarbons are removed at the bottom of the fractionating column
. Very short chain hydrocarbons do not condense (they have very low boiling points)
Where are very long chain hydrocarbons with very high boiling points removed?
At the bottom
Where are short chain hydrocarbons with very low boiling points removed?
They do not condense, they leave the column as gases they don’t condense rise straight away, (have very low boiling points)
What do the fractions contain
Hydrocarbons with a similar number of carbon atoms
Give some examples of some fuels that some fractions are used as
Petrol and diesel (for cars)
.kerosene(used as jet fuel for planes)
. Heavy fuel oil is used to power ships
.Liquified petroleum gas (is used in camping stoves)
explain another thing that fractions can be used as?
Feedstock for the petrochemical industry
Explain what is meant by feedstock?
A chemical that is used to make other chemicals
. Give items which feedstock fractions are used to make?
.solvents
.lubricants
.Detergents
.Polymers
Why may we use cracking?
To break up long chain hydrocarbons since they are not flammable and cannot make good fuels
What happens in cracking
A long chain hydrocarbon is broken down to produce a smaller and more useful hydrocarbon and an alkene
What else is produced when cracking?
An alkene
What do we use in catalytic cracking
High temperature and a catalyst
What is the job of the catalyst?
To speed up the reaction
What do we use in steam cracking?
High temperature and steam
What do alkenes have?
A double covalent bond between two carbon atoms
Why are alkenes useful?
They can be used to make chemicals like polymers and are used as a starting material for other useful chemicals too.
Are alkenes more or less reactive than alkanes?
They are more reactive due to double bound
Explain the experiment in which we can test for alkenes?
By shaking the substance with bromine water which is orange.
If an alkene is present the bromine water turns colourless.
What is the general formulae for alkenes
C(N)H(2N)
Where is the covalent bond?
between the carbon atoms
Name the molecular formulae of propene
C3H6
Why are alkenes unsaturated molecules?
Because they have two fewer hydrogen atoms than the alkane with the same number of carbon atoms
Which part of the alkene is the alkene functional group and why is it that?
The double bond is the alkene because that determines how it reacts .
What is meant by a functional group?
The part of a molecule that determines how it reacts
Describe what is meant by a homologous series?
Where all the members of the series have the same functional group e.g.(for alkenes its the double covalent bond)
What does each member in the homologous series have?
An extra carbon atom and two extra hydrogen atoms than previous alkene
What happens when we combust alkenes?
They produce carbon dioxide and water and also produces unburnt carbon particles meaning that alkenes burn in air with a smoky flame
Why are unburnt carbon particles produced?
Due to incomplete combustion
What name is used to describe the reaction when an alkene reacts with hydrogen?
A hydrogenation reaction
What is required for this hydrogenation reaction?
A nickel catalyst and 150 degrees celcius
What happens in this reaction?
The two hydrogen atoms add across the double bond and the carbon to carbon double bond is converted to a carbon to carbon single bond converting ethene to ethane.
Give the general formulae for the hydrogenation of an alkene
Alkene + hydrogen produces Alkane
Are alkenes a homologous series?
Yes
Why do all alkenes react in the same way?
They all have a double covalent bond (same functional group)
What happens when we add water too ethene in a hydration reaction
.We produce ethanol (an alcohol)
Name the conditions for the hydration of ethene
The water has to be in the form of steam, the temperature must be at around 300 degrees Celsius and the pressure around 70 atmospheres
What catalyst do we use?
Phosphoric acid
Is the reaction reversible (hydration of ethene)
Yes
What can we do with unreacted ethene and steam if the reaction is reversible?
We can pass them back through the catalyst to increase the yield of ethanol
look at the freesciencelessons picture of the hydration of ethene just in case
nothing to say
What happens when we react ethene with chlorine(halogen)
The two chlorine atoms in the chlorine molecule have been added across the double bond and the carbon to carbon double bond is now a carbon to carbon single bond and dichloroethane is formed
What is formed when ethene reacts with bromine
dibromoethane
What is formed when iodine reacts with ethene
diiodoeethane
Name three uses of alcohols?
In fuels, solvents and in alcoholic drinks
Are the alcohols a homologous series?
Yes
What does this mean?
Means they all have the same functional group? e.g.(OH)
Give the structural formulae for methanol
CH3OH
Give the structural formulae for propanol
CH3CH2CH20H
give one advantage of producing ethanol via the hydration of ethene
produces a high yield of ethanol
Give two disadvantages of producing ethanol via hydration of ethene
Requires a high temperature so lots of energy and uses ethene from crude oil which is a non-renewable source
Name another way we can produce ethanol?
Via fermentation
Describe the process of fermentation
In fermentation we start with a sugar solution such as glucose and mix this with yeast, the yeast converts the sugar solution to a solution of ethanol, Carbon dioxide gas is also produced.
Name two conditions for fermentation
Temperature of around 30 degrees Celsius, reaction must take place in anaerobic conditions (without oxygen)
Give two advantages of producing ethanol via fermentation
. Low temperature (does not require lots of energy)
. The sugar from this reaction comes from plants and therefore is renewable
Give a disadvantage of producing ethanol via fermentation
A aqueous solution of ethanol is produced ethanol dissolved in water so we have to distillate the solution to purify the ethanol and that requires energy
Are alcohols soluble in water? what do they from when reacted with water
They from neutral solutions and yes they are soluble in water
What decreases as the number of carbon atoms increases
solubility
What do we see when ethanol is reacted with sodium?
We see bubbles of hydrogen gas being produced
What product is made when ethanol and sodium react?
Sodium ethoxide plus hydrogen
What does propane and sodium give when reacted together?
Sodium propoxide plus hydrogen
What does sodium and butane produce?
Sodium butoxide plus hydrogen
Give a good example of an oxidising agent?
Acidified potassium dichromate
What do alcohols produce when reacted with an oxidising agent?
They produce a carboxylic acid plus water
What does methanol give when reacted with an oxidising agent?
Methanoic acid plus water
What does propanol and butanol give when reacted with an oxidising agent?
butanoic acid plus water
. Propanoic acid plus water
What is produced when combusting a alcohol
Carbon dioxide plus water, energy is also released
LOOk at diagrams freescincenlessons for carboxylic acids and more before
nothing to say
Are the carboxylic acids a homolgous series
Yes they all have the same functional group(COOH)
Give the structural formulae for Methanoic acid and and propanoic acid.
HCOOH
CH3CH2COOH
What are carboxylic acids in water?
They are weak acids
What happens when when ethanoic acid is in solution
What type of reaction?
It ionises to form ethanoate ion and hydrogen plus ions in a reversible reaction
Why are carboxylic acids weak acids?
They only partially ionise in aqueous solution
So they have a higher PH than strong acids e.g. hydrochloric acid
cba read the question its an info grab
What is the general formulae when a carboxylic acid reacts with a carbonate
we get a salt a carbon dioxide gas and water
What do we get when propanoic acid reacts with potassium carbonate
We get potassium propanoate plus carbon dioxide plus water
Is potassium propanoate a salt?
Yes
What do we produce when we react a carboxylic acid with an alcohol
we make an ester plus water
Where are esters used
In foods as they have a pleasant smell
What is the genera formulae for an alcohol and a carboxylic acid reacting together
they form ester plus water
what does ethanoic acid plus ethanol give
Ethyl ethanoate plus water
What is required for this reaction?
Sulfuric acid as a catalyst, this is a reversible reaction
Name three uses of polymers?
Plastic cups, plastic bottles and also shavers
How are polymers made?
By joining together thousands of small identical molecules, known as monomers
What are the monomers in addition polymers?
They are alkenes
Give a difference between the monomer and the addition polymer?
There is no double covalent bond between the two carbon atoms in the polymer however there is in the monomer
If the monomer is ethene what do we make?
Poly(ethene)
What does the word poly mean?
Many
How do we work out the repeating unit?
By getting two carbon atoms next to each other and drawing these out and the hydrogen atoms attached we then put brackets around going through the bond them and put an n in the bottom right corner
What does the n after the brackets tell us?
That the polymer consists of a large number of repeating units
Why does the repeating unit have the same number of atoms as the monomer?
Because there is nothing else formed in the reaction and everything in the monomer ends up in the polymer
Does the repeating unit have a double bond?
No
What are condensation polymers made up of?
Monomers too
Are the monomers in condensation polymers alkenes
No
What happens when these monomers react(condensation polymers)
Small molecules such as water are lost
Are all the monomers the same in condensation polymers?
No, we start with two different monomers. Each monomer has two of the same functional group
What can we do instead of draw the full structure of them monomers?
Put a box in the middle representing carbon chains and only show the functional groups
What condition do we need for to make water?
An OH and a H
What is the structure of glycine
H2NCH2COOH
How many functional groups are there in glycine and name them
2,Amine group and carboxylic acid group
Describe the amino functional group
A nitrogen atom covalently bonded with two hydrogen atoms
Give an example of an amino acid
Glycine
Why can amino acids react to form a condensation polymer?
They have two functional groups
Watch free science lessons on amino acids
dkjb
Why do we call the polymer made up of glycine a polypeptide?
It is only made up of one type of amino aicd
Do all amino acids have two functional gorups?
Yes
What polymer is made up of amino acid monomers?
Protein
What are long chain polypeptides known as?
Proteins
Name a natural occuring poymer?
Protein
Where is DNA found
in almost all living organisms animals plants bacteria fungi including some viruses
What do some viruses have instead of DNA
A related molecule
What does DNA do?
Decodes the genetic instructions that living organisms need to develop and to function
What does DNA contain?
Two polymer chains made from monomers called nucleotides
Name the four different types of nucleotide monomers
GATC
What do the two polymer chains in DNA do?
wrap around each other to form a double helix
What is starch and cellulose polymers of
glucose arranged in a slightly different way
