introduction to organic chemistry

bigger section to revise 

HideShow resource information

HYDROCARBON - are organic compounds that contain carbon and hydrogen only 

SATURATED HYDROCARBON - is a hydrocarbon with with single bonds 

1 of 22

UNSATURATED HYDROCARBON - conatins carbon-to-carbon multiple bonds

ALIPHATIC  HYDROCARBON - a carbon atoms joined together or in brached chains 

ALICYLIC HYDROCARBONS - carbon atoms joined together in a ring structure 

2 of 22


Chemical reactions occur at a definite rate determined by the reaction conditions. The rate of reaction may be increased by:

  1. Increasing temperature
  2. Increasing concentration of reactants
  3. Increasing surface area

Many reactions are subject to kinetic control.

3 of 22

Effect of Temperature rate of reaction

Collision theory 

  • Only those molecules having energy above a certain minimum value will react when they collide
  • This minimum energy value is called the activation energy
  • The activation energy can be thought of as anenergy barrier to the progress of the reaction.
4 of 22


Energy-profile diagrams:

5 of 22

  • The rate of reaction is directly related to the size of the activation energy.

The spread of energies in a sample of gas molecules is given by the Maxwell-Boltzmann distribution curve. Frequent collisions between molecules results in a spread of high and low energy molecules.

6 of 22

  • At the lower temperature T1, the number of molecules with energy greater than activation energy is given by the purple shaded area. 
  • An increase in temperature to T2 results in a large increase in the number of such molecules.
  • This increase is represented by the light blue shaded area.
  • Therefore, the number of 'productive collisions' will be much greater at higher temperatures and so the rate will not be much 
7 of 22

This is a high energy species in which old bonds are partially broken and new bonds are partially formed.

Copyright S-cool (

8 of 22



  • A catalyst speeds up a chemical reaction without itself undergoing any permanent chemical change.
  • They are usually specific to one particular reaction and they speed up both forward and back reactions equally.
9 of 22

  • All types of catalyst work by providing an alternative pathway that has a lower activation energy than the original one.

In the presence of a catalyst a new pathway is created.

10 of 22

Homogenous catalysis

Homogenous catalysts function in the same state as the reactants (usually all in aqueous solution).


CH3COOH(aq) + C2H5OH(aq) → CH3COOC2H5(aq) + H2O(l) is catalysed by the acid: H+(aq)

Enzymes are important homogenous catalysts.

11 of 22


An instrument called a mass spectrometer is used to calculate relative atomic mass.

In a mass spectrometer:

  • atoms are converted to positive ions; 
  •  then deflected by electric and magnetic fields before being detected.
  •  The mass of the elements individual isotopes are found as well as their abundance.

12 of 22


From this data the Relative Atomic Mass can be found.

Copyright S-cool (

13 of 22

Equilibrium of reactions

14 of 22

 Mechanism of bond breaking and making

A covalent bond can be broken in two ways:

a) Homolytic fission

  • A:B → Ao + Bo

Produces free radicals which have an unpaired electron and are very reactive.

15 of 22

 Heterolytic fission

  • A:B → A+ + B-
  • A:B → A- + B+

Produces ions.

16 of 22

dipoles come about when there is unequal distrubution between electronsin the molecule because some  tend to attractor repel electrons 

Chlorine has a greater share of the electrons due to the electronegativity it possesses:

17 of 22

Groups which are attracting electrons have a negative inductive (-I) effect. They give rise to electron deficient atoms Cδ+.

Groups which are electron repelling have a positive inductive (+I) effect. They give rise to electron rich carbon atoms Cδ-.

18 of 22

Organic reagents

Nucleophiles: Attack centres of low electron density (nucleus loving). They possess a lone pair of electrons and are usually negatively charged.

Examples include: H2O, ROH, OH-, RO-, Br-, NH3, RNH2, CN-.


Electrophiles: Attack centres of high electron density (electron loving) The are capable of accepting a lone pair of electrons and are usually positively charged.

Examples include: H+, Br+, R-N=N, CN-.

19 of 22

functional groups

Copyright S-cool Ltd ( S-cool Ltd ( S-cool Ltd ( S-cool Ltd ( S-cool Ltd ( S-cool Ltd (

20 of 22

FUNCTIONAL GROUP - the part of the organic molecule resposible for its reactions 

molecules with same functional group react in a similar way 

 HOMOLOUS SERIES- series of compound with same functional group but with each successive member differing by CH2

ALKANES-are homologous series with the general formula  CnH2n+2 

21 of 22


 addition polymerisation, alkenes add to themselves. 

The alkene is the repeating unit 

22 of 22


No comments have yet been made

Similar Chemistry resources:

See all Chemistry resources »See all Functional Groups resources »