1. Introduction Flashcards
What is organic chemistry?
The study of carbon containing compounds, both natural and synthetic
(apart from carbon monoxide and carbon dioxide)
How many covalent bonds is carbon able to form with carbon atoms or non-metals?
4
Why are there so many carbon compounds?
Carbon has the ability to form four covalent bonds with other carbon atoms or non-metals
Why are carbon forms relatively stable compounds?
The C-C bonds are strong and therefore difficult to break
What can carbon compounds be represented using?
- empirical formula
- molecular formula
- general formula
- structural formula
- displayed formula
- skeletal formula
What is an empirical formula?
The simplest ratio of atoms of each element in a compound - may require cancelling numbers down
What is the empirical formula for any simple alkene?
CH2
What is a general formula?
An algebraic formula that can be used to describe any member of a family of compounds
General formula for alkanes?
CnH2n+2
General formula for alkenes?
CnH2n
General formula for alcohols?
CnH2n+1OH
What is a molecular formula?
A formula that gives the total number of atoms of each element in each molecule of a substance
What is a structural formula of an organic compound?
Shows the atoms carbon by carbon, with the attached hydrogens and functional groups
What is the structural formula of propene?
CH3CHCH2
What is the structural formula of chloroethane?
CH3CH2Cl
What is a displayed formula?
Shows how all of the atoms in a compound are arranged and show all of the bonds between them
What is a skeletal formula of an organic compound?
Shows the bonds of the carbon skeleton with only functional groups displayed
Which atoms are never drawn in a skeletal compound?
Carbon and hydrogen
What features of molecules are included when naming them?
- the size and shape of the carbon skeleton
- the presence of functional groups
- the position of functional groups
Why is carbon so important?
- forms long chains and structures
- forms single, double and triple covalent bonds
- forms basis of most organic compounds
What does the carbon skeleton provide the name for?
The ‘backbone’ of the molecule around the rest is constructed
If a molecule’s carbon skeleton consists of 1 carbon atom, what will its name include?
Meth-
If a molecule’s carbon skeleton consists of 2 carbon atoms, what will its name include?
Eth-
If a molecule’s carbon skeleton consists of 3 carbon atoms, what will its name include?
Prop-
If a molecule’s carbon skeleton consists of 4 carbon atoms, what will its name include?
But-
If a molecule’s carbon skeleton consists of 5 carbon atoms, what will its name include?
Pent-
If a molecule’s carbon skeleton consists of 6 carbon atoms, what will its name include?
Hex-
What are main chains named after?
The maximum number of carbon atoms bonded in a ‘straight chain’
What are branched chains named after?
The number of carbons they contain
Where does the name of branched chains go when naming a molecule?
At the beginning; they form a prefix to which -yl is added
What is added to the end of names of branched chains?
-yl
How are ring structures named?
- cycloalkanes
* cycloalkenes
How can cycloalkenes also be known?
Arenes
What compound are arenes based on?
Benzene
What are arenes?
Aromatic compounds
What is a functional group?
The part of the molecule where reactions take place
What does the functional group of a compound identify?
Its homologous series - and is therefore used to name it
What is a homologous series?
A group of compounds that contain the same functional group
What is the functional group of alkenes?
C=C
What is the functional group of alcohols?
-OH
What is the functional group of carboxylic acids?
-COOH
In a homologous series, how will each member differ from the other?
CH2
How does being in the same homologous series affect the properties of compounds?
- physical - length affects physical properties
* chemical - properties are the same
What do physical properties of organic compounds differ with?
- size
* degree of branching
What are examples of physical properties of organic compounds?
Melting and boiling point
How will increased chain length affect the melting and boiling point of molecules?
- increase melting and boiling points
* because strength of intermolecular force between molecules increases
How will increased branching affect the melting and boiling point of molecules?
- decrease melting and boiling points
* because molecules cannot pack together as easily (weaker intermolecular forces between molecules)
If there is no functional group, what will the name of the molecule end with?
‘ane’
What is the functional group in haloalkanes?
A halogen
What is the functional group in aldehydes?
O=C-H