Topic 5- Introduction to Organic Chemistry and Alkanes Flashcards
Define a homologous series
A group of organic compounds that have the same functional group, but each successive member differs by CH2.
Characteristics of a homologous series
- Each member has the same functional group
- Each member has the same general formula
- Each member has similar chemical properties
Characteristics of a homologous series
- Each member has the same functional group
- Each member has the same general formula
- Each member has similar chemical properties
How are alkanes saturated hydrocarbons?
They are compounds containing only hydrogen and carbon atoms.
Define Structural Isomerism
What are the 3 types?
Compounds that have the same molecular formula but a different structural formula.
- Chain
- Position
- Functional group
Chain Isomers
When there is more than one way of arranging the carbon chain of a molecule.
Position Isomers
Have the same carbon chain but the functional group is bonded to different carbons.
Functional group isomers
Have the same molecular formula but have different functional groups.
Stereoisomers
Have the same structural and molecular formula, but a different arrangement of atoms in space.
What leads to E-Z isomerism?
The restricted rotation about a planar carbon carbon double bond.
What`s the criteria for E-Z isomerism?
- A carbon carbon double bond must be present
- Each carbon atom must be attached to two different groups
Describe Z-isomers
When the highest priority groups are on the same side of the double bond (together).
Describe E-isomers
When the highest priority groups are on different sides of the double bond (opposite).
Describe fractional distillation
A process in which a mixture of liquids is separated into groups of compounds with similar boiling points.
How do the alkanes separate in the fractionating column?
-As vapor is passed into the fractionating column it moves up the column and gets cooler.
- Owing to the different chain lengths and boiling points of the different hydrocarbon, each fraction condenses at different temperatures.
What is cracking?
The breakdown of large alkanes into smaller, more useful molecules by breaking the C-C bonds.
Requires high temperatures to break the strong C-C bonds.
Catalytic cracking
- High temperature (450 degrees)
- Slight pressure
- Zeolite catalyst
- Produces motor fuels and aromatic hydrocarbons
Thermal cracking
- High temperature (1000 degrees)
- High pressure
- No catalyst
- Produces high percentage of alkenes (useful to make polymers)
Complete combustion
Occurs in a plentiful supply of air and produces carbon dioxide and water.
Incomplete combustion
Occurs when there is a limited supply of air. The reaction produces carbon monoxide, water and sometimes soot.
How is carbon monoxide produced in the internal combustion engine?
How is it a pollutant?
- Incomplete combustion of the fuel in limited oxygen.
- Binds to hemoglobin instead of oxygen.
How are hydrocarbons produced in the internal combustion engine?
How is it a pollutant?
- Not all of the fuel burns, and some unburnt hydrocarbons leave the exhaust.
- Hydrocarbons react with oxides of nitrogen (NOx) to form ground level ozone, which is a component of smog.
How are Oxides of Nitrogen produced in the internal combustion engine?
How is it a pollutant?
- Nitrogen from the air reacts oxygen at high temperature and pressure in the engine.
- Oxides of nitrogen react with unburnt hydrocarbons to produce photochemical smog. Oxides of nitrogen dissolve in water to form acid rain.
How is Carbon produced in the internal combustion engine?
How is it a pollutant?
- Incomplete combustion of the fuel in very limited oxygen.
- Carbon particles exacerbate asthma.
