Organic Chemistry Flashcards
What are the three main fossil fuels
Coal
Natural gas
Petroleum
What is petroleum made of
Consists of organic compounds that are sometimes referred to as hydrocarbons, as they only contain hydrogen and carbon atoms.
What are the name of each column in the fractional distillation
Describe how the properties of fractions obtained from petroleum change from the bottom to the top of the fractionating column
Fractions with molecules that contain a small number of carbon atoms, such as gasoline, will have relatively low boiling points so they will evaporate first and rise up the tower. As the fractions reach the top of the tower where it is much cooler, they will condense back into a liquid and can be collected.
Hydrocarbons that contain a slightly higher number of carbon atoms, for example kerosene, will have a corresponding higher boiling point so that as it moves up the distillation tower, it will condense at a higher temperature midway along the distillation tower and be collected.
Hydrocarbons that contain a high number of carbon atoms, such as fuel oil for ships, will have a very high boiling point and will therefore not have to travel much through the distillation tower before it condenses again and is collected.
What is a structural formulae
An unambiguous written description that shows how the atoms in a molecule are arranged
What are the general characteristics of a homologous series
Same functional group
Same general formula
Similar chemical properties
What are structural isomers
Compounds with the same molecular formula but different structural formulae
What is the homologous series
Alkanes
Alienes
Alcohols
Carboxylic acids
What are the properties of alkanes
Bonds in alkanes are always single covalent bonds, so alkanes are saturated
This means that they are not reactive since electrons are all occupied and the atoms are held together by string covalent bonds
Alkanes are generally unreactive because their molecules do not contain a reactive functional group
Alkanes react with chlorine
Sometimes incomplete combustion occurs when there is a lack of oxygen
What is a replacing atom
In a substitution reaction, an atom or group of atoms in a molecules is replaced by a different atom or group of atoms.
This usually involves the functional group, but in alkanes it involves one of the hydrogen atoms
how do you make chloroalkanes
Alkanes can undergo substitution reactions with chlorine to produce chloroalkanes and hydrogen chloride
Ultraviolet light is needed to provide the activation energy for the reaction or it will not happen
The reactions are described as photochemical reactions because they need light
What is cracking?
Cracking is a chemical process that breaks down larger alkane molecules to produce smaller alkane molecules and aliene molecules
Hydrogen is also produced in the reaction
Cracking needs high temperatures and a catalyst
What is unsaturated compounds
Compounds that contain C=C double bonds between carbon atoms
Like alkenes
What are the reasons for cracking
Fractional distillation of petroleum is used to produce useful mixtures of hydrocarbons.
Fractions that contain smaller alkanes are more useful as fuels than fractions that contain larger alkanes.
This is because alkanes consisting of smaller molecules flow more easily and are easier to ignite.
However, fractional distillation alone usually cannot produce enough of these substances to match the demand for them
How does alkenes react with bromine
Bromine water turns from brown to colour less
This is because the C=C breaks, allowing for the addition of bromine
When this happens the bromine water loses its characteristic brown colour, indicating that bromine is no longer present as it has reacted with an alkene
