Pages

Monday, March 7, 2011

Chemistry Form 5: Chapter 2 - Differences between Alkanes and Alkenes


 Alkanes  Alkenes
General formula  CHnH2n+2  CHnH2n
 Naming  All the members end with 'ane'  All the members end with 'ene’
 Physical state Members having 1-4 carbon atoms per molecule are gases/5-17 carbon atoms are liquids and 18 or more are solids at room temperature Members having 2-4 carbon atoms per molecule are gases/5-15 carbon atoms per molecule are liquids and the higher members are solids
Melting and boiling points The melting and boiling points increases with increase in molecular mass. The melting and boiling points increases with the increase in molecular mass
 Solubility They are insoluble in water; soluble in benzene, alcohol, ether and carbon tetrachloride. They are insoluble in water; soluble in benzene, ethanol and ether.
 Combustion They undergo complete combustion production CO2 , H2O and heat. They burn with a sooty flame because of the higher percentage of carbon in them producing CO2 , H2O and heat.
Substitution reaction Undergo substitution substitution reaction in the presence of sun light  Do not undergo substitution reaction.
Addition reaction Do not undergo addition reaction as they are saturated  Undergo addition reactions
Reaction with bromine water  Do not decolorise bromine water  Decolorise bromine water
 Reaction with acidified KMnO4 Do not decolorise acidified KMnO4 solution Decolorise acidified KMnO4 solution

  Saturated Hydrocarbon Unsaturated Hydrocarbon






Bromine Test


Acidified Potassium Manganate (VII) solution Test


Combustion of alkene produces more soot than alkane

No comments:

Post a Comment