4) Organic Chemistry Flashcards
Hydrocarbon
Compound that contains only hydrogen and carbon atoms
Types of formulae
-empirical
-molecular
-general
-structural
-displayed
Empirical formula
Shows the simplest possible ratio of the atoms in a molecule
Molecular formula
Shows the actual number of atoms in a molecule
General formula
The simplest algebraic formula of a member of a homologous series
Displayed formula
Shows the relative positioning of atoms and the bonds between them
-all bonds form
Structural formula
Minimal detail that shows the arrangement of atoms in a molecule
-e.g. CH3CH2CH2CH2CH3 - pentane
Homologous series
Series of organic compounds that have similar features and chemical properties due to them having the same functional group
-same general formula
-same functional group
-similar chemical properties
-gradation in their physical properties
-difference in the molecular formula between one member and the next is CH2
Functional group
A group of atoms bonded in a specific arrangement that influences the properties of the homologous series
e.g. alkene C=C
Isomerism
Compounds that have the same molecular formula but different displayed formulae
Naming compounds - prefix/ suffix
Prefix: tells you how many carbon atoms are present in the longest continuous chain in the compound
Suffix: tells you what functional group is on the compound
Naming compounds - stem
Stem: number of carbon atoms
-meth - 1
-eth - 2
-prop - 3
-but - 4
-pent - 5
-hex - 6
Naming compounds - prefix
Cl - chloro
Br - bromo
I - iodo
CH3 - methyl
Naming compounds - suffix
-alkane - ane
-alkene - ene
-alcohol - ol
-carboxylic acid - oic acid
Substitution reaction
Takes place when one functional group is replaced by another
e.g. Methane + Bromine → Bromomethane + Hydrogen Bromide
-methane reacts with bromine under UV light
-alkanes react via substitution (UV light needed)
Addition reaction
Takes place when two or more molecules combine to form a larger molecule with no other products
e.g. Ethene + Bromine → Dibromoethane
-alkenes react via addition
Combustion
An organic substance reacts with oxygen to form carbon dioxide and water
-if it is incomplete: produce carbon monoxide and water
Crude oil
-mixture of hydrocarbons
-not very useful but different hydrocarbons in it are valuable
-therefore needs to be separated from each other - fractional distillation
Process of fractional distillation
- Crude oil is vaporized and pumped into the fractionating column which is cooler at the top than the bottom
- The vapours rise up the column until they reach their boiling points
- The hydrocarbons condense at their boiling points and are pumped out the column in fractions
- Smaller molecules have lower boiling points so condense further up the column
Main fractions of crude oil
Shortest chain
-refinery gases
-gasoline
-kerosene
-diesel
-fuel oil
-bitumen
Longest chain
Trend in characteristics - going from shortest to longest chains
-boiling point increases
-viscosity increases
-colour decreases
-volatility decreases
-usefulness decreases
-abundance increases
Use of refinery gases
-fuel for domestic heating
-cooking
-bottled gases
Use of gasoline
-fuel for cars