C7 - Organic Chemistry Flashcards
How is crude oil formed?
Layers of rock build up over dead matter.
Pressure and heat are applied.
What are crude oil’s uses?
Burned for energy - electricity, transport, heating
Bitumen (roads)
What is crude oil?
A mixture of hydrocarbons.
What are hydrocarbons?
Molecules made of only hydrogen and carbon, where all the bonds are single.
What is the formula for all alkanes?
C(n) H (2n+2)
What is the chemical symbol for methane?
CH(4)
What is the chemical symbol for ethane?
C(2)H(6)
What is the chemical symbol for propane?
C(3)H(8)
What is the chemical symbol for butane?
C(4)H(10)
What does volatility mean?
How easy it evaporates.
What does viscosity mean?
Thickness
What are the properties of short chain molecules?
Low boiling point
More flammable
Low viscosity
High volatility
What are the properties of long chain molecules?
High boiling point
Less flammable - smokey flame
High viscosity
Low volatility
Why do long chain molecules have a higher boiling point and are less flammable than short chain molecules?
Bigger molecules - stronger intermolecular forces
What is combustion?
An exothermic reaction with oxygen to release light and heat.
What are the 3 things needed for combustion?
Fuel, oxygen and heat.
What does the reaction between a hydrocarbon and oxygen produce?
Carbon dioxide and water.
Why does incomplete combustion occur?
Because there is insufficient oxygen available.
What forms in incomplete combustion instead of carbon dioxide?
Carbon monoxide and carbon particulates.
Explain the fractional distillation of crude oil.
Vaporise crude oil, remove residue.
Hydrocarbons rise.
As gas rises, temp. decreases.
At it’s boiling point the hydrocarbons condense and fractions seperated.
What is the word equation for the incomplete combustion of methan?
Methane + oxygen –> carbon monoxide + carbon + water
What is cracking?
Breaking down long hydrocarbons to smaller, more useful hydrocarbons.
Why do we use cracking?
Because long chain hydrocarbons are not that useful as they are thick liquids or solids with high boiling points so cannot be used for fuel.
What are two types of cracking?
Catalytic and steam
List the steps for catalytic cracking.
- Long HC chains are vaporised
- Passed over hot catalyst
- Heated to a high temperature
- Thermal decomposition breaks down chain
- Large chain splits into smaller chains
List the steps for steam cracking.
- Long HC chains are vaporised
- Mix with steam at a high pressure.
- Heated to a high temperature
- Thermal decomposition breaks down chain
- Large chain splits into smaller chains
What is the formula for an alkene?
C(n)H(2n)
What is the difference between an alkene and alkane?
Alkane is made up of single bonds (saturated)
Alkene has a double bond (unsaturated)
What is the product of catalytic cracking?
An alkane and an alkene (splits into two chains)
What is the product of steam cracking?
Lots of small molecules (alkane + lots of alkenes)
What happens when an alkene is added to orange bromine water?
Bromine water is decolourised.
What happens when an alkane is added to orange bromine water?
No reaction - stays the same colour.
What is a homologous series?
A family of organic compounds with the same functional groups and chemical compounds.
What is the equation for complete combustion of hydrocarbons?
Hydrocarbon + oxygen –> carbon dioxide + water
What is the equation for incomplete combustion of hydrocarbons?
Hydrocarbon + oxygen –> carbon monoxide + carbon particulates + water
What is an addition reaction?
Where a double bond is broken and two new single bonds form. To make one product.
How are alcohols made?
Alkene + water (hydrating an alkene with steam)
What is the general formula for alcohol?
C(n)H(2n+1)OH
What does H2O split into in addition reactions?
OH and H
How does the length of the chain relate to how well it mixes with water
Short chains - mix well
Long chains - don’t mix well
How are carboxylic acids made?
By oxidising alcohols with an oxidising agent.
What is the general formula for a carboxylic acid?
C(n)H(2n+1)COOH
Are carboxylic acids unsaturated or saturated?
Unsaturated.
What does propanoic acid split into when ionised in water?
C2H5COO (negative) and H+
Are carboxylic acids weak or strong?
Weak meaning they only partially ionise in water.
What is the general equation for a carboxylic acid and a carbonate?
Acid + carbonate –> salt + carbon dioxide + water
What is the equation for the reaction between butanoic acid and lithium carbonate?
Lithium butanoate + carbon dioxide + water
How is an ester formed?
Carboxylic acid + alcohol –> ester - in the presence of a sulfuric acid catalyst
Why is water formed as a by product when creating an ester?
OH is cut off from the carboxylic acid and H is cut off from the alcohol.
What is the word equation for methyl and ethanoic acid?
Methyl + ethanoic acid -> methyl ethanoate
What are the two types of polymerisation reactions?
Addition polymerisation
Condensation polymerisation
What is a polymer?
A long molecule formed when small molecules (monomer) are joined together.
What is addition polymerisation?
Forms from a monomer with a double bond.
What is condensation polymerisation?
Forms from monomers with two functional groups (diol and dicarboxylic acid) and produces a second product of H2O or HCI.
What is the equation for condensation polymerisation?
Monomer –> polyester + water
What does a diol and dicarboxylic acid form?
Diol + dicarboxylic acid –> polyester + water
What is DNA?
Genetic material that makes up chromosomes.
What are alkanes?
Saturated hydrocarbons with the general formula C(n)H(2n+2).
What are the physical properties of alkanes?
- First few in series are gases, then change to liquids, then change to solids.
- Boiling points increase as molecules get bigger.
- Viscosity increases as molecules get bigger.
- Volatility decreases.
- Flammability decreases.
- Poor reactivity.
What types of reaction is cracking?
Thermal decomposition reaction.
What is an alkene?
Unsaturated hydrocarbon (contains a double bond)
What is the test for alkenes?
Add bromine water.
What happens during the combustion of alkenes?
Burns with a smoky flame due to incomplete combustion.
Why do alkenes burn more often incompletely than alkanes?
Alkenes are more reactive because of their double bond, and therefore needs a rapid supply of oxygen.
What are the characteristics of alcohols?
Dissolve in water to form neutral solution.
React with sodium to form hydrogen.
Burn in oxygen.
React with carboxylic acids in presence of acid catalyst to form esters.
What are some uses of alcohols?
Fuels
Solvents
Drinks
What are the characteristics of carboxylic acids?
Dissolve in water to form acidic solution (H+ ions)
React with metal carbonates to form carbon dioxide.
React with alcohols with acid catalyst to form esters.
React metals to give off hydrogen gas.
What type of acid is carboxylic acid?
Weak acid.
What is the word equation for the fermentation of glucose?
Glucose –> ethanol + carbon dioxide
What are the conditions required for the fermentation of glucose?
30 degrees celsius, aqueous solution of glucose, absence of air, yeast added.
Why are carboxylic acids weak?
They are partially dissociated in water.
What is a dicarboxylic acid monomer?
Contains two carboxylic acid groups.
What is a diol monomer?
Contains two alcohol groups.
What is the ester link?
When the carbon from the dicarboxylic acid bonds directly to the oxygen from the diol.
What is the difference between condensation polymers and addition polymers?
Condensation polymers are biodegradable because bacteria can break down the ester link.
Addition polymers are not as they are plastics.
What is an amide bond?
Similar to an ester bond but with O replaced with N. Contains the C = O group.
What is an amino acid?
Organic compound containing both a carboxylic acid and functionality (COOH) and an amine functional group (NH2).
How do amino acids make proteins?
By numerous condensation polymerisation reactions. Amino acids (monomers), proteins (polymers).
What are polypeptides?
Made by the condensation polymerisation reaction of amino acids, but are shorter than proteins.
What are carbohydrates?
Organic molecules made of C, H and O e.g. starch and cellulose.
Are polymers made of glucose.
What is DNA’s structure?
Two polymer chains held together in a double helix.
Each polymer chain is made from 4 different monomers - nucleotides.
What is an example of a condensation polymer?
Polyester.
What molecule are addition polymers made from?
Alkenes
What does addition polymerisation reactions require?
Catalyst
High pressure
Properties of esters.
Sweet smelling
Volatile
Esters usage.
Perfumes.
Food flavourings.
How do you show carboxylic acids to be a weak acid with an equation?
Reversible equation symbol. Carboxylic acid -><- ionised version (e.g. propanoate ion + hydrogen ion)
Why is crude oil a finite resource?
Because it takes longer to form than the rate at which we are using it up.
Name the first 4 alkanes.
Methane
Ethane
Propane
Butane
What is fractional distillation?
A process used to separate mixtures of hydrocarbons with different boiling points.
Which molecules are collected at the top of the fractional distillation column and why?
Small molecules as they have the lowest boiling point.
Why is fractional distillation important?
Because the different fractions of crude oil have different uses.
What is a fuel?
A substance that when reacted with oxygen releases energy.
Name five fuels we obtain from crude oil.
petrol
diesel
kerosene
heavy fuel oil
liquefied petroleum gases
What other uses are there for products of fractional distillation?
Solvents, lubricants, polymers and detergents.
Why are the reactions of alkenes with hydrogen, water and halogens known as “addition” reactions?
Because new atoms are being “added” to the molecule by breaking the double bond.
What is the product from the reaction of an alkene with hydrogen?
An alkane.
What conditions are necessary in the reaction of alkenes with hydrogen?
60 degrees Celsius, nickel catalyst.
What is the product from the reaction of an alkene with a halogen?
A halogenoalkene.
What is the product from the reaction of an alkene with steam?
An alcohol.
What conditions are necessary for the reaction of alkenes with H2O?
High temperature (to make steam), acid catalyst.
What happens when an alcohol reacts with sodium?
It forms a salt and releases hydrogen gas.
What are the products of a combustion reaction involving an alcohol and oxygen?
Carbon dioxide and water.
What is fermentation?
The process of turning glucose (a natural sugar) into ethanol.
What forms when a carboxylic acid reacts with a metal?
A salt and hydrogen.
What forms when a carboxylic acid reacts with a metal oxide?
A salt and water.
What forms when a carboxylic acid reacts with a metal hydroxide?
A salt and water.
What forms when a carboxylic acid reacts with a metal carbonate?
A salt, water and carbon dioxide.
What conditions are needed to form an ester?
Heat. Sulphuric acid catalyst.
What are the products of condensation polymerisation?
A polymer and a small molecule (usually water).
What is an amino acid?
A biological molecule with two functional groups.
Which functional groups do amino acids have?
NH2 and -COOH
What do amino acids form during a condensation reaction?
Polypeptides and water.
What is formed from different amino acids combined in one chain?
Proteins
What does DNA stand for?
Deoxyribonucleic acid.
What is DNA?
A large molecule containing genetic information.
What is the structure of DNA?
Two polymer chains made from 4 different nucleotides in the form of a double helix.
Name four naturally occurring polymers.
DNA
proteins
starch
cellulose
What monomers is DNA made of?
Nucleotides
What monomers are starch and cellulose made of?
Glucose
What is a halogenoalkane?
An alkane with two halogen atoms, one on each carbon where the double bond used to be.
