Topic 10 Organic chem Flashcards
Catenation
Connected in a chain or series (Eg: carbon forming long chains of covalent bonds)
Homologous series
a family of hydrocarbons with similar chemical properties who share the same general formula (eg: alkanes, alkenes)
First 4 members of the alkane homologous series
Methan, ethane, propane, butane
General formula for alkane–use it to state the molecular formula of hexane
C(n)H(2n+2)
C6H14
Functional group
A functional group is responsible for the characteristic property or behavior of a class of compounds. For example, hydroxyl ( –OH) group in alcohols.
what are the 13 main class names and their functional group names and suffixes
Alkane–N/A (-ane) Alkene–alkenyl (-ene) Alkyne–alkynyl (-yne) Alcohol–hydroxyl (-anol) Ether–ether (-oxyalkane) Aldehyde–carbonyl (-anal) Ketone–carbonyl (-anone) Carboxylic acid–carboxyl (-anoic acid) ester–ester (-anoate) amide–carboxyamide (-anamide) amine–amine (-anamine) nitrile–nitrile (-anenitrile) arene–phenyl (-benzene)
Common features of homologous series
1) same general formula
2) Same functional group
3) a gradual trend in their physical properties (eg:boiling points, density, viscosity) with the rise of molecular mass
4) differ by a -CH2- group
5) similar chemical properties (though the first may differ)
The relationship between molecular mass with melting and boiling points + intermolecular strength in a homologous series
Use this to explain the physical states of alkanes
- As the molar mass increases, the strength of the intermolecular forces between the molecules also increases, which results in a higher melting and boiling point.
- The first 4 members of the alkane series are gases, then it becomes liquids then waxy solids.
Draw the functional group structure of alkenes
Hence, draw ethene
Draw the functional group structure of alkynes
Hence, draw ethyne
Draw the functional group structure of alcohol
Hence, draw ethanol
Draw the functional group structure of ether
Hence, draw methoxyethane (no. of carb + ether + alkane)
Draw the functional group structure of aldehyde
Hence, draw propanal
Draw the functional group structure of ketone
Hence, draw propanone
Draw the functional group structure of amide
Hence, draw propanamide
Draw the functional group structure of amine
Hence, draw ethanamine
Draw the functional group structure of nitrile
Hence, draw propanenitrile
Draw the functional group structure of arene
Hence, draw ethyl benzene
Draw the functional group structure of carboxylic acid
Hence, draw propanoic acid
Draw bromomethane
Draw methyl methanoate
General formula of alkene
C(n)H(2n)
General formula of alkyne
C(n)H(2n-2)
General formula of alcohol
C(n)H(2n+1)OH
General formula of ether
R–O–R’ (carbon chains on either sides)
General formula of aldehyde
R–CHO
General formula of Ketone
R–CO–R’
General formula of carbolyxic acid
C(n)H(2n+1)COOH
General formula of ester
R–COO–R’
List first 6 prefixes of carbon chains
Meth, eth, prop, but, pent, hex
Which is the correct order when the following alkanes are placed in order of decreasing boiling point?
1) C4H10 > C3H8 > C2H6 > CH4
2) CH4 > C2H6 > C3H8 > C4H10
3) C4H10 > C2H6 > CH4 > C3H8
4) C4H10 > CH4 > C2H6 > C3H8
1
Empirical formula
The simplest whole number ratio of atoms in a compound (eg: CH3)
Molecular formula
The actual number of each type of atom in a compound (Eg: C2H6)
Full structural formula
all atoms and the bonds between the atoms are shown (Drawn diagram)
Condensed structural formula
The same as full structural formulae but the bonds are committed (Eg: CH3CH2CH2CH3)
Skeletal formula
using lines, all atoms are omitted leaving only the backbone of the molecule. Single bonds are represented by one line and double bonds are represented by two lines (eg: the skeletal formula of propan-1-ol (CH3CH2CH2OH) omits the carbon and hydrogen atoms)
stereochemical formula
shows the relative three-dimensional positions of atoms or groups around a selected carbon atom
- a bond sticking out from the plane of the page (towards the viewer) is shown as a solid wedge, whereas a bond directed behind the page (away from the viewer) is shown as a broken line
Naming rules
1) Identify the longest straight chain of carbon atoms (eg: meth, prop)
2) Identify the functional group (eg: alkyl, alkenyl, ether)
3) Identify the side chain or substitudent (eg: mthyl, ethyl)
Structural isomers–give an example
Compounds with the same molecular formula but different arrangements of atoms (different structural formulae)
- eg: pentane and 2-methylbutane
position isomerism
when the functional group is attached in different positions
Draw But-1-ene and But-2-ene
Draw propene