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Properties of Hydrocarbons - Coggle Diagram
Properties of Hydrocarbons
Intramolecular bonding
strong covalent bonds
between C-C, C-H
alkenes
1+ double bonds
alkynes
1+ triple bonds
intermolecular bonding
weak dispersion force
non-polar
little difference in electronegativity
of C and H atoms
no dipole-dipole forces
no hydrogen bonding
Physical Properties
density
lower density than water
float on water
water stronger intermolecular forces
increasing mass per unit volume
solubility
insoluble
water is polar
cannot bond with
non-polar hydrocarbons
dissolve substances - form bonds
viscosity
resistance to flow
depends on intermolecular forces
larger hydrocarbons = larger intermolecular force
= more viscous
melting and boiling points
low melting and boiling points
as molecules get larger
dispersion forces increase
more energy needed to break them
boiling point increases
at 25oC
C1-C4 alkanes
gases
lowest boiling points
C5-C16
liquids
C17+
solids
branching chains
little effect
lower boiling point slightly
more extended shape
forces holding molecules together breaks
boiling point
energy to break intermolecular bonds/forces
chemical properties
combustion
complete combustion
in air/oxygen
form CO2 + H2O
use of hydrocarbons as fuels
alkenes + alkynes
burn more vigorously
double/triple bonds
more sooty flame
% of C is higher
incomplete combustion
in limited supply of oxygen
form H2O & CO/C
dehydrogenation of alkanes
dehydrogenation in ethane
produces ethene
important industrial reaction
CH3-CH3->CH2=CH2 + H2
alkanes not as reactive as alkenes/alkynes
double/triple bond = more easily broken
substitution reactions - alkanes
alkanes
saturated compounds
not very reactive
undergo substitution reactions
atom of another element
substituted for one of H atoms
needs: occur in light, energy (UV)
addition reactions - alkenes/alkynes
occur in unsaturated organic compounds
double/triple bond is broken
other atoms added
energy not needed
take place in dark or in UV light
alkenes
with hydrogen, water, halogens, hydrogen halides