Intro To Organic Chemistry Flashcards
What is molecular formula
The actual number of atoms of each element present in the molecule of a compound
What is empirical formula?
The ratio of each atom present in the molecule of a compound
What is structural formula?
A formula which gives information about the way the atoms in a molecule are connected and arranged in a space
What is displayed formula?
Shows every bond and atom and the arrangement of atoms
What is steletal formula?
Shows a shorthand representation of the molecular structure
-Zigzags where every bend is 1 C atom
What are the rules of nomenclature
- Number of carbons (e. g. meth, eth, prop)
- Functional group e.g. C =c is “ene”, - oh is “ol”, - cooh is “oic acid”
- Start with lowest number for functional group and longest chain with functional group
- same substituent occur more than once:di,tri,tetra
- 2 or more different substituent: alphabetical order
What is homolytic fission
Breaking a covalent bond whereby each atom acquires one electron producing free radicals
What is a free radical?
An atom or group with an unpaired electron formed from the homolytic fission of a covalent bond and are very reactive
What is heterolytic fission?
Breaking of a covalent bond whereby one atom acquires both electrons and the other none, producing positive and negative charged ions
What is a nucleophile?
Anions or molecules with a lone pair of electrons and are attracted to electron deficient sites
-E.g. Cn-, br-, H2O, NH3
What is an electrophile?
Species which are electron deficient and are attracted by the electron rich sites
-Eg.H+,Cl+,
What happens in an addition reaction?
- involves 2 molecules joining together to form a single new molecule
- usually involves reactions with unsaturated compounds
What happens in a substitution reaction?
Involves replacing an atom (or a group of atoms) by another
What happens in an elimination reaction?
Involves the removal of a molecule from a larger molecule
What happens in hydrolysis?
Involves breaking covalent bonds by reaction with water
What is the product of electrophillic addition?
Alkenes
What is the product of nucleophillic addition?
Carbonyl
What is the product of free radical substitution?
Alkanes
What are the products of nucleophillic substitution?
Halogenoalkane + alcohol
What is isomerism?
Compounds that have the same molecular formula but different structural formula
What is structural isomerism?
Different structural formula and different spatial arrangement of atoms
What are the types of structural isomers?
- chain isomerism
- position isomerism
- Functional isomerism
What is stereoisomerism?
Same structural formula, different spatial arrangements of atoms
What are the types of stereoisomers?
- geometric isomers
- Optical isomers
Why do structural isomer have different structural formulas
- Because their atoms are linked together in different ways
- It arises owing to arrangement (branching) of carbon stele-ton
What is positional isomerism?
- Type of structural isomerism
- Based on position of functional group
What is functional group isomerism?
- Type of structural isomerism
- based on different functional group
What are stereoisomers?
- Stereoisomer have the same structure and bond order but their atoms and groups of atoms are arranged differently in space
- They have different spatial arrangements and their molecules are not superimposable
What are geometrical isomers?
- Type of stereoisomer
- must have c =c double bond
- on each carbon in the c= c, there must be 2 different atoms/groups of atoms
What are optical isomers?
- the molecule must have all single bonds
- carbon atom which has 4 different atoms or group at atoms
- they exist in pairs, in which one isomer is the mirror image of the other
- 2 optical isomers are non-super impossible but are identical (mirror image)
- these isomers are called enantiomers
What are cis-trans isomers?
- involves a double bond, usually c=c, that does not allow free rotation (restricted rotation) about the double bond (unlike a c-c single bond)
- the cis molecule is the one with the most number of electrons on one side
- the formation of cis-trans isomerism is due to the restricted rotation of the c= c double bond
- Cis-trans isomerism cannot exist if either carbon carries 2 identical groups
What is the difference between cis-trans isomers chemical property?
Cis-trans isomers have similar chemical properties (same functional group) and they react with the same reagents but at different rates
What is the difference in physical properties between cis-trans isomers?
- cis trans isomers have different physical properties due to different spatial arrangements of groups
- trans isomers usually have higher melting points and lower boiling points due to weak induced dipole-dipole forces
What are the physical properties of cis isomers?
- The structure of cis isomer is less symmetrical
↳ hence cannot be closely packed in the crystal lattice
↳ less contact between neighbouring molecules
↳ strength of intermolecular forces reduced - cis isomers generally have lower melting point and higher boiling point due to high polarity
Why do trans isomer have high melting points out Low boiling point
They have high MP due to lots of dipole moments (more bonds to break) but Low b.p. As the dipoles cancel out and they are held by weak id-id forces
What is a chiral carbon
The Central carbon atom to which four different atoms or groups are attached
What is the criteria for optical isomerism?
- The compound must have all single bonds
- carbon atom which has 4 different atoms/groups of atoms
what is the alkane general formula
CnH2n+2
what is alkene general formula
CnH2n
alcohol general formula
CnH2n+1OH
what is a functional group
the group of atoms responsible for the characteristic reactions of a compound
what is a homologous series
a series of organic compounds with the same functional group and with successive members differing by -CH2
what is an alkane
a saturated hydrocarbon with general formula CnH2n+2
what is an alkene
an unsaturated hydrocarbon with the general formula CnH2n
what is a halogenoalkane
an alkane where a hydrogen atom has been replaced by a halogen atom
what is an alcohol
organic compound with lone hydroxyl group (-OH) attached to alkyl group with general formula CnH2n+1OH
how are alcohols classified
- primary
- secondary
- tertiary
what is primary alcohol
the carbon bonded to the hydroxyl group is bonded to two r groups
what is secondary alcohol
the carbon bonded to the hydroxyl group is bonded to 2 r groups
what is tertiary alcohols
the carbon bonded to the hydroxyl group is bonded to three R groups
what is aldehydes
an organic compound with the -CHO functional group
what is ketone
organic compound with the RCOR’ functional group
What is a carboxylic acid?
Organic compound with the -cooh functional group
What is ester
Organic compound formed from a condensation reaction between an alcohol and a carboxylic acid
What is primary amine?
A derivative of ammonia, in a primary amine, one hydoyan atom in ammonia is substituted with an alkyl group
What is a nitrile
Organic compound with - cn functional group
What is an aliphatic hydro carbon?
A compound containing only carbon and hydrogen atoms in which the carbon atoms are arranged in a linear or branched structure
What are the three steps in a free radical substitution mechanism?
1 initiation
- Propagation
- Termination
What is a condensation reaction?
The formation of a compound with the release of a small molecule, such as water
What is oxidation
Oxidation reactions involve the loss of electrons and gain of oxygen leading to the increase in oxidation number
What is reduction
Reduction reactions involve the gain of electrons and lead to a decrease in oxidation number
Describe the shape and bond angles in ethane
Shape; tetrahedral
Angle: 109.5
Shape and bond angles of ethene
Shape: trigonal planar
Angle: 120
How to determine whether a stereoisomer is cis or trans?
- In trans isomers high priority groups are on opposite sides of the c=c bond
- In cis isomers , high priority groups are on the same side of c=c
What are high priority groups in cis trans isomers
- Single atoms; atom with highest mass
- molecules : highest atomic mass of atom attached to c=c
