Organic Chemistry Flashcards
Homologous series; Alkanes (saturated) and Alkenes (unsaturated)
A homologous series is a group of organic molecules with similar chemical properties. (All compounds in homologous series have the same general formula).
Alkanes are saturated hydrocarbons. This means that their carbon atoms are joined to each other by single bonds (C-C).
Straight chain alkenes formula: Cn H2n+2
Alkenes are unsaturated hydrocarbons. This means that some of their carbon atoms are joined to each other by double bonds.
Straight chain alkenes formula: Cn H2n
Hydrocarbons
Hydrocarbons are molecules which only contain carbon and hydrogen atoms.
Isomers
Organic molecules having the same molecular formula but a different structural formula.
e.g. structural isomers of C5H12 = pentane, 2-Methylbutane, 2,2-Dimenthylpropane
Nomenclature (naming rules)
1 . Meth-
- Eth-
- Prop-
- But-
- Pent-
- Hex-
- Hept-
- Oct-
Fractional Distillation
Fractional distillation separates a mixture into a number of different part, called fractions.
A tall fractionating column is fitted above the mixture.
The column is hot at the bottom and cool at the top.
Substances with high boiling points condense at the bottom and the substances with lower boiling points condense on the way to the top.
The crude oil is evaporated and its vapors condense at different temperatures in the column. Each fraction contains hydrocarbon molecules with a similar number of carbon atoms and a similar range of boiling points.
Boiling Point (difference between shorter and longer hydrocarbons)
The smaller the molecule, the lower the boiling point because there are less intermolecular forces between the molecules.
And therefore, less energy required to break them.
Cracking definition
Large hydrocarbon molecules can be broken down into smaller molecules using a catalyst.
e.g. thermal decomposition reaction
Cracking Method
Catalytic cracking can be done in the laboratory by heating mineral wool soaked in oil with a catalyst, producing a gas.
Oil will likely be a long chain hydrocarbon, the catalyst is heated and the oil because the oil is flammable. The product being gaseous suggests that we have produced molecules with a smaller size that that of the oil.
Alcohols (homologous series)
Organic compounds containing a hydroxyl (-OH) group = called alcohols.
Carboxylic acids (homologous series)
Carboxylic acids = a homologous series. Functional group: COOH Name end in: -oic acid This functional group = always carbon 1 General formula: C(n)H(2n+1)COOH
Production of ethanol (fermentation and hydration)
Alkyl Halides
F = fluoro Cl = chloro Br = bromo I = iodo
Polymerisation
The formation of a large molecule (polymer) from many monomer subunits.
Monomers to polymers
Polymers to monomers
