Introduction Organic Flashcards
what is a hydrocarbon?
Hydrocarbon is a compound consisting of hydrogen and carbon only
what is the difference between saturated and unsaturated?
Saturated: Contain single carbon-carbon bonds only Unsaturated : Contains a C=C double bond
what does the molecular formula show?
Molecular formula: The formula which shows the actual number of each type of atom
what does the empirical formula show?
Empirical formula: shows the simplest whole number ratio of atoms of each element in the compound
what is the general formula?
General formula: algebraic formula for a homologous series e.g. CnH2n
what does the structural formula show?
Structural formula shows the minimal detail that shows the arrangement of atoms in a
molecule, eg for butane: CH3CH2CH2CH3 or CH3
(CH2
)2CH3
,
what does the displayed formula show?
Displayed formula: show all the covalent bonds and atoms present in a molecule
what is the shape around a saturated hydrocarbon and what is the bond angle?
tetrahedral
109.5
what is a functional group?
Functional group is an atom or group of atoms which when present in different molecules
causes them to have similar chemical properties
what is a homologous series?
Homologous series are families of organic compounds with the same functional
group and same general formula. •They show a gradual change in physical properties (e.g. boiling point).
• Each member differs by CH2
from the last.
• same chemical properties.
what are the orders of priority groups, highest first?
Carboxylic acids >aldehydes>ketones>alcohols>alkenes>halogenoalkanes
what is the difference between an aldehyde and a ketone?
aldehydes have the C=O at the end whereas ketones have it elsewhere
how is a -OH named on an aldehyde?
Aldehydes have a higher priority than alcohol so the –OH
group uses the hydroxy prefix
e.g. 4- hydroxybutanol
how do you reflect 2 ketone groups in the namings? give an example
If two ketone groups then di is put before – one and an e is added to the stem.
e.g.
pentane-2,4-dione
what is the name if there are carboxylic acids on both ends of the chain?
If there are carboxylic acid groups on both ends of the
chain then it is called a - dioic acid
what are the 2 ways to break a covalent bond?
- homolytic fission
- heterolytic fission
define homolytic fission
each atom gets one electron from the covalent bond- this forms 2 free radicals
- this is demonstrated using a 1 headed arrow
define heterolytic fission
one atom gets both electrons- this produces an ion
-this is demonstrated using a double headed arrow
define free radical
Free radicals do not have a charge and
Definition
A free radical is a reactive species
which possess an unpaired electron
what is a structural formula? what are the 3 types they arise from?
Structural isomers: same molecular formula different structures (or structural formulae) Structural isomerism can arise from •Chain isomerism •Position isomerism •Functional group isomerism
what is a chain isomer?
Chain isomers: Compounds with the same molecular formula but different
structures of the carbon skeleton
e. g.
- pentane, 2-methylbutane, 2,2- dimethylpropane
what is a position isomer?
position isomers: Compounds with the same molecular formula but different structures due to
different positions of the same functional group on the same carbon skeleton
e. g.
- 1-bromopropane, 2-bromopropane
what is a functional group isomer?
Functional group isomers: Compounds with the same molecular formula but with
atoms arranged to give different functional groups
e. g.
- ethanol(alcohol), and methoxymethane(an ether) or cyclohexane and hexene
what is sterioisomerism?
Stereoisomers have the same structural formulae but
have a different spatial arrangement of atoms.
why is there E-Z isomerism?
E-Z stereoisomers arise when:
(a) There is restricted rotation around the C=C double bond.
(b) There are two different groups/atoms attached both ends of the
double bond
what is a priority group?
Priority Group: The atom with the bigger
atomic number is classed as the priority atom
what are the CIP priority rules?
- Compare the atomic number of the
atoms directly attached to each side of the
double bond; the atom of higher atomic
number is given priority. - If the atoms are the same, consider the
atoms at distance 2 from the double bond.
Make a list of each atom bonded to the one
directly attached to the double bond.
Arrange list in order of decreasing atomic
number. Compare the lists atom by atom; at
the earliest difference, the group containing
the atom of higher atomic number is given
priority
what effect does E-Z isomerism have on physical properties?
E-Z isomers can have different boiling points.
Z-1,2-dichloroethene
Boiling point =60oC
This molecule is polar. The polar C-Cl bonds are on
the same side of the molecule. One side of the
molecule is slightly negative.
The intermolecular forces are both van der waals
and permanent dipole-dipole attractions.
E-1,2-dichloroethene
Boiling point =48oC
This molecule is non- polar. The polar C-Cl
bonds are on opposite sides of the molecule.
The dipoles cancel out.
The intermolecular forces are only van der
waals so lower boiling point.
