Alkanes Flashcards
Why can carbon form so many compounds
- can form 4 covalent bonds
- can form single, double or triple bonds
- can bond to other carbon atoms to form long chains
Definition of aliphatic
A compound containing carbon and hydrogen joined together in straight chains, branched chains or non-aromatic rings.
Definition of alicyclic
An aliphatic compound arranges in non-aromatic rings with or without side chains
Definition of aromatic
A compound containing a benzene ring
Definition of saturated
Single carbon-carbon bonds only
Definition of unsaturated
The presence of one or more carbon double bond
Definition of homologous series
A series of organic compounds having the same functional group but with each successive member differing by CH2.
Definition of a functional group
The part of the organic molecule responsible for its chemical reactions.
General formula of alkanes
CxH2x+2
Names of alkanes
1 carbon- methane 2 carbons- ethane 3 carbons- propane 4 carbons- butane 5 carbons- pentane 6 carbons- hexane 7 carbons- heptane 8 carbons- octane 9 carbons- nonane 10 carbons- decane
Draw cyclopentane using molecular, structural, displayed and skeletal formulas
Check page 12 of study pack
Naming alcohols
Contain suffix-ol
Always count from end which will give alcohol lowest number
use di, tri as well for more than 1 alcohol
Naming alkanes with side chains
methyl group- CH3
ethyl group- CH2CH3
Write at beginning of name e.g 3-methylpropane
Definition of general formula
Simplest algebraic formula of a member of a homologous series
Definition of structural formula
The minimal detail that shows the arrangement of atoms in a molecule
Definition of displayed formula
The relative positioning of atoms and the bonds between them
Definition of skeletal formula
The simplified organic formula shown by removing hydrogen atoms from alkyl chains leaving just a carbon skeleton and associated functional groups.
Structural isomers
Are compounds with the same molecular formula but different structural formula
Draw structural isomers with formula C4H8
Check study pack p 31
Definition of stereoisomers
Have the same structural formula but a different arrangement of groups in space
Definition of chain isomers
different arrangement of carbon atoms
Definition of functional group isomers
different functional group altogether
Defintion of positional isomers
different positions of functional groups
Complete combustion of alkanes equation
CxHy + (x+y/4) O2 –> xCO2 + y/2 H2O
Incomplete combustion of alkanes equation
- CO is produced
2. only C is produced
Why is incomplete combustion bad
Carbon monoxide is released which is toxic.
State conditions needed for alkanes to react with halogens
UV light
Write reaction of bromine with ethane using structural formula
CH3CH3 + Br2 –>CH3CH2Br +HBr
Definition of a radical and show the symbol
A radical is a species with an unpaired electron.
The symbol is a dot
What is the name of the mechanism in the reaction between methane and bromine
Radical substitution
What are the names of the 3 stages involved in the reaction between and alkane and halogen
Initiation, Propagation and termination
What happens in the initiation stage
The halogen is broken in to two radicals under the presence of UV light
Br2 –> 2Br.
The name of this type of bond breaking is homolytic fission
Write equations for propagation stages using bromine and methane
Br. + CH4 –> CH3. + HBr
CH3. + Br2 –> CH3Br + Br.
Write 3 equations for the termination stage using bromine and methane
2CH3. –>C2H6
2Br. –> Br2
CH3. + Br. –>CH3Br
3 limitations of using radical substitution in organic synthesis
- Further substitution can occur
- Substitution at different positions on the C chain can occur
- The C chain may change length (double)
It is difficult to synthesis only desired compounds
Write general formula for a cycloalkane
CnH2n
Define homolytic fission
The breaking of a covalent bond to form two radicals- one electron from each pair goes to each atom
