P2: Organic Chemistry Flashcards
What is crude oil?
The remains of plankton and other living material buried in mud millions of years ago.
Where is crude oil found today?
Rocks, and people have to drill underground to get it.
Is crude oil finite or infinite?
A finite resource, meaning it will eventually run out.
What is crude oil made up of?
A mixture of different hydrocarbons
What is a hydrocarbon?
A compound made only from carbon and hydrogen atoms.
What is the general formula for alkanes?
C(n) H(2n+2)
What are alkanes?
Saturated hydrocarbons
What are the names of the first 4 alkanes?
Methane, ethane, propane and butane.
What are the hydrogen and carbon atoms connected by in alkanes?
Single covalent bonds.
What are the different groups of hydrocarbons called?
Fractions.
How are the different hydrocarbons separated in crude oil?
Fractional distillation.
Do long hydrocarbons have higher or lower boiling points?
Higher. As a result, long hydrocarbons condense nearer the bottom of the column.
What is the first step in fractional distillation?
Evaporate the crude oil by heating it. This causes most of the hydrocarbons to evaporate and rise up the fractional distillation column.
Do short hydrocarbons have lower or higher boiling points?
Lower. As a result, short hydrocarbons condense near the top of the fractional distillation column where it is cooler.
List some of the fuels that crude oil fractions are used as.
Petrol, diesel oil, kerosene, heavy fuel oil, liquified petroleum gas. Others are chemical products used in everyday life, such as solvents, lubricants, detergents and polymers.
What are alkenes?
Desaturated hydrocarbons. These are more reactive than alkanes.
Why are alkenes more reactive than alkanes?
Because of the presence of a double bond in alkenes.
What is the standard formula for alkenes?
C(n) H(2n)
How do you test for alkenes?
Place bromine water into the container with the alkenes. Bromine water changes from orange to colourless.
What can alkenes be used for?
Making polymers and a range of other chemical products.
Describe the properties of longer hydrocarbons.
They have higher boiling points, higher viscosity and low flammability.
Describe the properties of shorter hydrocarbons.
Lower boiling points, lower viscosity and high flammability.
What is the chemical term for burning?
Combustion
What happens when hydrocarbons combust?
Energy is released. This makes them useful as fuels.
What are the products of complete combustion?
Carbon dioxide and water.
Show the word equation of complete combustion of a hydrocarbon.
Hydrocarbon + Oxygen -(heat)—> Carbon Dioxide + Water
What is the name of the process to break down longer hydrocarbons?
Cracking
Why is cracking done?
To break longer hydrocarbons into smaller ones, and to meet the demand for fuel.
What are the two different methods of cracking?
Catalytic cracking and steam cracking.
What does catalytic cracking involve?
Passing the hydrocarbon over a hot catalyst at low pressure.
What are the products of cracking?
A mixture of smaller alkanes and alkenes.
What does steam cracking involve?
Long hydrocarbons reacting with steam at high temperatures.
What type of reaction is it when alkenes react with other reactants?
An addition reaction
What happens to the carbon bond in alkenes during an addition reaction?
The double bond becomes a single bond to allow the two carbon atoms to make new bonds.
What is the functional group for alkenes?
C=C (two Carbons with a double bond)
Which ones are more likely to combust incompletely: alkenes or alkanes?
Alkenes
What causes incomplete combustion?
A lack of oxygen.
Describe the flame produced when alkenes burn.
A smoky flame.
What are the products of incomplete combustion?
Carbon, carbon monoxide and water.
What do alkenes react with to produce alcohol?
Water vapour. It needs a temperature of ~300° and a catalyst.
What is the functional group of an alcohol?
-OH. All alcohols’ names end in “-ol”.
What is released when alcohols react with sodium?
Hydrogen gas.
What do alcohols release when they burn in air?
Energy, carbon dioxide and water. This means alcohols can be used as fuels.
What happens when alcohols are added to water?
They dissolve to form a neutral solution.
What do alcohols react with to form carboxylic acids?
Oxidising agents.
What chemical is used to convert sugar into ethanol?
Yeast
What is the process whereby yeast converts molecules into ethanol?
Fermentation
What are the products of fermentation?
Ethanol and Carbon Dioxide.
What is fermentation?
The process of converting sugar into ethanol using yeast.
What kind of conditions does fermentation require?
Anaerobic conditions, and temperature should be ~30° Celsius
Describe the process of fermentation.
Mix sugar solution with yeast. Yeast converts sugar solution into a solution of ethanol.
What are the advantages of using fermentation to produce ethanol?
-The low temperature means that the reaction requires little energy,
-The sugar from the reaction comes from plants, so therefore it is renewable.
What is a disadvantage of fermentation to produce ethanol?
The product is an aqueous solution of ethanol. We then need to purify the ethanol by distillation, which requires energy.
What is the functional group of carboxylic acids?
-COOH
What do all carboxylic acids’ names end in?
“-oic acid”.
What is produced when carboxylic acids react with metal carbonates?
A salt, water and carbon dioxide.
What is formed when carboxylic acids dissolve in water?
They form weak acids. This is because they only partially ionise in water.
What is formed when carboxylic acids react with alcohols?
Esters. Water is also formed, but this is a separate molecule. A condensation reaction.
What is the ester functional group?
-COO-
Describe two properties of esters.
-Insoluble in water
-Characteristic smells
How are esters formed?
Condensation reaction between a carboxylic acid and an alcohol.
What are polymers?
Long chain organic molecules.
What are polymers formed from?
Many smaller molecules called monomers.
What are the two types of polymerisation?
Addition polymerisation and condensation polymerisation.
What are the monomers like in addition polymerisation?
Small and unsaturated molecules. The monomers are all alkenes.
What is produced during addition polymerisation?
Only the polymer. No other molecules.
How are condensation polymers formed?
When monomers with functional groups at both ends react together.
What is condensation polymerisation?
The polymerisation involving monomers with two different functional groups.
Why are condensation polymers called that?
Because small molecules such as water are also produced during the reaction.
What are DNA molecules made of?
2 polymer chains coiled together in a double helix.
What are the polymer chains in DNA made from?
4 different monomers called nucleotides
What is deoxyribonucleic acid?
DNA, A natural polymer.
What does DNA do?
Encodes the genetic information needed for living organisms and viruses to function.
What monomers are starch and cellulose polymers formed from?
Glucose monomers. They are linked in a different way to give the two different polymers.
Give the general name of the four different monomers which make up the structure of DNA.
Nucleotides
What do amino acids contain?
An amino group (-NH2) and a carboxyl group (-COOH)
What can amino acids be polymerised to make?
Polypeptides and proteins.
What is an oxidising agent?
Something that gains electrons. Makes the other reactant lose electrons. For example sulfuric acid.
What is a homologous series?
A group of organic compounds that have similar chemical properties, due to them having the same functional group
What is a feedstock?
A raw material used to provide reactants for an industrial reaction
What is a petrochemical?
A substance made from crude oil via chemical reactions.
What type of reaction is cracking?
Thermal decomposition, because heat is used to break it up.
What is PRODUCED when alcohol reacts with sodium?
A salt and hydrogen
