Chapter 16 (16.3-16.8) Nomenclature Flashcards
what are the three types of hydrocarbons
alkanes, alkenes, alkynes
characteristics of a homologous series
same functional group
same general formula
same chemical properties
Consecutive members differ by CH2
boiling and melting points increases down a homologous series
common methods of preparation
Viscosity increases
Flammability decreases
What is a functional group (definition)
An atom or group of atoms in a molecule that dictates how the compound will react
which hydrocarbon is unsaturated
alkene, alkyne
Are alkenes or Alkanes more reactive
why
Alkenes - double bond easier to break
what is the general formula of alkanes
CnH2n+2
eg:- carbon = 7
then hydrogen = 2(7)+2 therefore 16
C7H16
functional group of alkane
single bond between carbons
properties of alkanes
insoluble in water
The boiling point of alkanes increases with increasing molecular weight.
The melting point of alkanes increases with an increase in molecular weight.
naming alkanes
1) select longest chain (straight, L shaped)
2) number closest to the branch
3) all other groups not part of the longest chain should be taken as a branch
4) if there is more than one group present as a branch then written as di,tri etc. and branches are named in alphabetical order eg ethyl, methyl. ethyl comes first
what is methane
ch4
what is ethane
c2h6
what is propane
c3h8
what is butane
c4h10
combustion reaction of alkanes
Alkane + oxygen –> co2 + h2o
eg: CH4 + 2o2 –> CO2 + 2H2O
What is a substitution reaction
Example
One atom or a group of atoms is replaced by another atom or group of atoms
Eg: Photochemical Reaction
photochemical reaction of alkane
occurs only under presence of light
Alkane + Halogen —–light—–> Alkyl-Halide + Acid
CH4 + Cl2 —–light—–> CH3Cl + HCl
What does the light do in a photochemical reaction
provides the activation energy required for the reaction
What happens as the amount of chlorine increases in photochemical reaction
More and more hydrogen atoms are substituted by chlorine atoms
properties of alkynes
have one less hydrogen than their alkane (methane ch4 /methyl ch3)
general formula of alkenes
CnH2n
what is the functional group of alkenes
double bond between the carbon
naming alkenes
1) select longest chain
2) naming starts closest to the double bond