C7- Organic Chemistry Flashcards
What are alkanes
The simplest type of hydrocarbon
Alkanes are a _ series
Homologous
What is a homologous series
a group of organic compounds that react in a similar way
Alkanes are _ compounds
Saturated
What is a saturated compound
Each carbon atom forms four single covalent bonds
What are the first four alkanes
- Methane
- Ethane
- Propane
- Butane
As the length of the carbon chain _ , the properties of the hydrocarbon _
Change
Change
Hydrocarbons with shorter carbon chains are also more …
Volatile
The shorter the carbon chain, the more _ the hydrocarbon is
Flammable
hydrogen + oxygen →
carbon dioxide + water (+energy)
Is crude oil a fossil fuel
Yes
How is crude oil formed
From the remains of plants and animals, mainly plankton, that died millions of years ago and were buried in mud. Over millions of years, with high temperature and pressure, the remains turn into crude oil, which can be drilled up form the rocks where it’s found
What is fractional distillation used for
To separate hydrocarbon fractions
What is crude oil a mixture of
Lots of different hydrocarbons,most of which are alkanes
How does fractional distillation work
- The oil is heated until most of it has turned into gas. The gases enter a fractionating column
- In the column there’s a temperature gradient
- The longer hydrocarbons have high boiling points. They condense back into liquids and drain out of the column early on, when they’re near the bottom. The shorter hydrocarbons have lower boiling points. They condense and drain out much later on, near to the top of the column where it’s cooler
- You end up with the crude oil mixture separated out into different fraction. Each fraction contains a mixture of hydrocarbons that all contain a similar number of carbon atoms, so have similar boiling points
What are the uses of crude oil
- Oil provides the fuel for most modern transport
- The petrochemical industry
- All the products you get font crude oil are examples if organic compounds
Are short or long chain compounds hydrocarbons flammable
Short-chain hydrocarbons
How to do cracking (splitting up log-chain hydrocarbons)
- Thermal decomposition reaction - breaking molecules down by heating them
- The first step is to heat long-chain hydrocarbons to vaporise them (turn onto gas)
- Then the vapour is passed over a hot powdered aluminium oxide catalyst
- The long-chain molecules split apart on the surface of the speks of catalyst - this is catalytic cracking
- You can also crack hydrocarbons if you vaporise them, mix them with steam and then heat them to a very high temperature. This is known as steam cracking
What is meant by cracking
Splitting up log-chain hydrocarbons
What kind of bond does alkenes have
C=C double bond
General formula for alkenes=
CnH2n
Alkene + oxygen →
Carbon + Carbon Monoxide + Carbon Dioxide + Water (+energy)
What does incomplete combustion result in
A smoky yellow flame and less energy
Alkenes react via _ reactions
Addition
What is a ‘functional group’
a group of atoms in a molecule that determined bow that molecule typically reacts
Do all alkenes react in a similar way and why
Yes, they all have ‘C=C’
What is addition of hydrogen known as
Hydrogenation
What does steam react with alkenes to form
Alcohols
Do halogens react with alkenes
Yes
What are polymers made of
Lots of the same molecule joined together in one long chain
What are plastics made up of
Long-Chain Molecules called polymers
What is the reaction called to produce polymers
Polymerisation
What kind of bond do monomers that make up addition polymers have
Double covalent bonds
How do you draw the displayed formula of an addition polymer form the displayed formula of its monomer
- start by drawing the two alkene carbons, replace the double bond with single bond and add an extra single bond to each pf the carbons
- Then fill in the rest of the groups in the same way that they surrounded the double bond in the monomer. Finally , stick a pair of brackets around the repeating bit, and put an ‘n’ after it (to show that there are lots of monomers)
How do you get from the displayed formula of the polymer to the displayed formula of the monomer
Do the reverse
What is the general formula of alcohols
CnH2n+1OH
What are properties that the first four alcohols have
- Flammable
- They undergo complete combustion
- Soluble in water. Their solution have a neutral pH
- They react with sodium
- They can be oxidised by reacting with oxygen to produce a carboxylic
Alcohols are used as - and _
Solvents and fuels
Sugar →
ethanol + carbon dioxide
What functional group do carboxylic acids have
COOH
Do carboxylic acids react like other acids
Yes
ethanol acid + sodium carbonate →
Sodium ethanoate + water + carbon dioxide
Can carboxylic acids dissolve in water
Yes
What happens when carboxylic dissolves in water
They ionise and release H+ ions resulting in an acidic solution
What functional group is esters in
-COO-
How are esters formed
From an alcohol and a carboxylic acid
Alcohol + carboxylic acid →
Ester + water
Polymers can be made by _ polymerisation
Condescension
How many types of monomers are there with addition polymerisation
Only one monomer type containing a C=C bond
How many types of monomers are there with condensation polymerisation
Two monomer types each contains two of the same functional groups or One monomer type with two different functional groups
How many products are there with addition polymerisation
Only one product formed
How many products are there with condensation polymerisation
Two types of product - the polymer and a small molecule
What are the functional groups involved in polymerisation with addition polymerisation
Carbon-carbon double bond in monomer
What are the functional groups involved in polymerisation with condensation polymerisation
Two reactive groups on each monomer
What are the two functional groups of amino acids
- A basic amino group (NH2)
2. An acidic carboxyl group (COOH)
Proteins are _ of Amino Acids
Polymers
True/ False
Amino acids can’t form polymers known as polypeptides via condensation polymerisation
False they can
What are DNA molecules made from
Nucleotide
Simple sugars can form _
Polymers
What is the most basic of organic compounds
Alkanes ( not alkalies)
Alkanes are all _ hydrocarbons
Saturated
What does saturated mean in the context “saturated compounds”
They have no double bonds between carbons
True/ False
Alkanes are ONLY hydrogen and oxygen
True
What is the formula of alkanes for the amount of hydrogen to the amount of oxygen in the form Cn + H_
2n+2
What is the chemical formula for methane
CH4
What is the chemical formula for ethane
C2H6
What is the chemical formula for propane
C3H8
What is the chemical formula for butane
C4H10
What is visocity
How runny/ well it flow a substance is
What are the first 4 alkanes
Methane, Ethane, Propane, Butane
Remember it by Monkeys Eat Peanut Butter
Alkalane + Oxygen →
Carbon dioxide + water
Crude oil is a mixture of different _
- Fractional distillation separates crude oil into fractions of similar _ hydrocarbons
- It works by heating crude oil so the hydrocarbons _
- As they rise up the column they _ and condense back to a liquid
- Similar length hydrocarbons have similar _ points so are collected at the same height
Hydrocarbons Length Boil Cool Boiling
What makes better fuels , hydrocarbons with smaller molecules or larger molecules
Smaller
Why are hydrocarbons with smaller molecules more desirable
- Are more volatile - turn into a gas more easily
- Are less viscous - they flow more easily
- Are more easily ignited
- Burn with a cleaner, less sooty flame
What does cracking mean ( regarding alkanes)
breaking down long alkanes into shorter alkanes (and alkenes)
What are the two different types of cracking
- Catalytic cracking - passed over a catalyst of silica or alumina
- Stean creaking- heated to 600-700°c
Alkanes are _ hydrocarbons
unsaturated
For is the formula for alkenes Cn H_
2n
Define Addition reactions
Where a small molecule adds across the c=c double bond to produce one product
Alkene + hydrogen →
Alkane
How to test for alkenes
You can use bromine water. Bromine water is orange. Alkenes decolourise orange bromine water when added to it
What is the functional group for methanoic acid
-COOH
Describe what you would obserb if a few drops of methonioc acid were added to Universal indicator solution in a test tube
Methanoic acid would dissolveand the universal indicator would change o orange/red
Methanoic acid reacts with calcium carbonat. What gas is evolved
Carbon dioxide
Explain why the carboxylic acid is shown as a week acid
It does not ionise completely when dissolved in water
Whatis the chemical formula for methonal
CH3OH
Whatis the chemical formula for ethonal
C2H5OH
Whatis the chemical formula for propanal
C3H7OH
Whatis the chemical formula for butanol
C4H9OH
What is the functional group for alcohol
-OH
Ethane + steam →
Ethonal
How do you make esters
- Add five drops of alcohol and 5 drops of carboxylic acid to the test tube
- Get your teacher to add concentrated 3 drops of sulphuric acid
- Heat for a few minutes in a beaker of hot water from the kettle
- Add about 20ml sodium carbonate to a separate small beaker
- Pour contents of test tube into a small beaker
How many functional groups does each monomer need to have to undergo condensation polymerisation
Two
How many functional groups are in amino acids
Two
Name one of the functional groups present in glycine
Carboxylic acid/ amine
What type of reaction results in the formation of polypeptides from amino acids
Condensation polymerisation
State the name of the small molecule lost during the formation of polypeptides
Water
What type of molecule are the monomers in starch
Sugars
Name one naturally occurring polymer that is made up of the same type of monomers as starch
Cellulose
What is the role of DNA
DNA contains genetic instructions for the operation and functioning of living organisms and viruses.
Describe the general structure of DNA
Two polymer chains made from four different nucleotide monomers linked together by cross links to give double helix structure
DNA is _ polymer chains, made from _ different monomer call nucleotide, in the form of a double helix
2
4
What is the monomer for starch and cellulose
Glucose
What is the monomer for proteins
Amino acids