Flashcards in Module 4: Chapter 11&12 Organic Chemistry & Alkanes Deck (32)
Define general formula
The simplest algebraic formula of a member of a homologous series e.g. CnH2n+2
Define structural formula
The minimal detail that shows the arrangement of atoms in a molecules e.g. CH3CH2CH2CH3
Define displayed formula
Shows the relative positioning of atoms and the bonds between them
Define skeletal formula
Simplified organic formula, shown by removing hydrogen atoms from alkyl chains, leaving just a carbon skeleton and associated functional groups
Define homologous series
A series of organic compounds having the same functional group but with each successive member differing by CH2
Define functional group
A group of atoms responsible for the characteristic reactions of a compound
- alkanes is the only family that doesn't have a functional group
A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings
An aliphatic compound arranged in non-aromatic rings with or without side chains
A compound containing a benzene ring
A molecule with single carbon to carbon bonds only
A molecule with multiple carbon-carbon bonds including double and triple carbon-carbon bonds and aromatic rings
Define structural isomers
compounds with the same molecular formula but with a different structural formulae
Define homolytic fissions
When a bond breaks and each bonding atom receives one electron from the bonded pair to form 2 radicals
Define heterolytic fission
When a bond breaks and one bonding atom receives both electrons from the bonded pair to form ions
A species with an unpaired electron
What are the rules for naming alkanes?
1. find the longest continuous carbon chain
2. identify any substituent group
3. number carbon atoms in longest chain to indicated position of any substituent groups (start numbering from the end that produces lowest set of numbers)
4. if same alkyl group appears more once indicated in name with di-, tri- and tetra- and use commas to separate numbers
5. names of different substituents are arranged alphabetically regardless of numbers
Why is carbon special?
- all carbon compounds are covalent
- each carbon atom forms 4 covalent bonds
- carbon forms strong covalent bonds with itself to form rings and chains
What are hydrocarbons?
only contain carbon and hydrogen and have the general formula CxHy
What is the molecular formula?
Gives the number of different types of atom in the molecule
What is the empirical formula?
Gives the ratio of the different types of atom in the molecule
What are the 3 types of structural isomers?
Chain, position and functional group
Describe position isomerism
in compounds containing a functional group, the functional group can be at different positions along the carbon chain
Describe functional group isomerism
molecules containing different functional groups have the same molecular formula
What are alkanes?
- hydrocarbons; they contain carbon and hydrogen only
- they are saturated, only single carbon-carbon bonds
- general formula of CnH2n+2
What are the first 10 alkanes?
What are the bonds and shape of alkanes?
- Alkanes contain single C-C bonds
- 2 s orbitals overlap to form a bond between the 2 carbon atoms that share a pair electrons, this is a sigma (σ) bonds
- alkanes have a tetrahedral structure with a bond angle of 109.5°
What are the boiling points of alkanes?
The boiling point is determined by the intermolecular force present and the size of the molecule (chain length)
- in crude oil there are lots of variations of boiling points so oil refineries separate crude oil into fractions by fractional distillation
- the greater the chain length, the greater the London forces, the higher the boiling point
- longer chains have a larger surface area, more contact between molecules, London forces are greater, more energy required to overcome forces
- same applies to the shape of the chain, the more branching, the less surface area of contact and the weaker the London forces
What is the alkane reactivity?
- strong sigma bonds throughout
- non polar bonds throughout
- generally not very reactive
Describe combustion of alkanes?
- alkanes combust very well
- in plentiful supply of oxygen complete combustion results in the production of H2O and CO2