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Properties of Organic and
Inorganic Compounds
Experiment 1
Chem 121
Organic Chemistry Laboratory
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What is ORGANIC
CHEMISTRY?
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Introduction
Vital force – ‘vitalism’
 Friedrich Wohler overthrew vitalism

◦ Synthesis of urea from ammonium cyanate
O
+
NH4

-
C
N
H2N
NH2
Distinguishing feature: organic compounds
all contain the CARBON atom
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What is ORGANIC chemistry?

the study of carbon containing
compounds
◦ Other elements in organic compounds: H, O,
N, S, P, Cl, Br, I and other transition metals

Why Carbon?
◦ Can share four valence electrons
◦ Form strong covalent bonds
◦ Form rings and long chains, e.g. benzene and
DNA
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Definition of terms

Ionic compounds: compounds made up of
a metal cation and a nonmetal anion
◦ e.g. NaCl, KNO3

Intramolecular forces of attraction: forces
existing within molecules that holds the
atoms together
◦ e.g. Ionic bond, covalent bond, metallic bond

Intermolecular forces of attraction: forces
existing between molecules
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Intermolecular Forces of Attraction

Ion-dipole
◦ Between an ionic compound and a polar
compound
 e.g. NaCl dissolved in water

Dipole-dipole
◦ Between two polar compounds
 e.g. HCl dissolved in water
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
Hydrogen Bonding
◦ Requirement: H atoms bonded to F, O, N
◦ Strongest intermolecular force
◦ e.g. NH3 in H2O

London dispersion forces/van der Waals
forces
◦ Between two NONPOLAR compounds
◦ Weakest intermolecular force; present in all
organic molecules
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The larger the size of
the organic compound,
the larger the London
dispersion forces.
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Properties of Organic Compounds

Flammable
◦ Due to the C-C bond energies in organic
compounds
◦ Energy released is in the form of heat

Ethanol vs. Water
◦ Ethanol – produces the distinct blue flame
◦ Water – smothers flame instead of generating
one
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
Charring
◦ also known as burning, scorching
◦ organic compounds are sensitive to heat
◦ End result of charring: elemental C

Sucrose
• disaccharide
• common ingredient in
sweet foods like ice
cream, candy
• also works as a food
preservative
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IMF of sucrose: London dispersion force
 IMF of NaCl and CaCO3: no
intermolecular force, but intramolecular
(IONIC BOND)
 Remember always: Intramolecular forces
are way STRONGER than intermolecular
forces.

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
Solubility
◦ relies on the intermolecular forces of organic
compounds
◦ ‘like dissolves like’
◦ Polar solvents dissolve in polar solutes.
◦ Nonpolar solvents dissolve in nonpolar
solutes.
◦ Organic compounds = mostly nonpolar
 It only follows that most organic compounds are
soluble in organic solvents.
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
Naphthalene in ether
O
H3C
CH3
◦ No ionic bonds, just pure London dispersion forces

Naphthalene in water
O
H
H
 Water is capable of hydrogen bonding; naphthalene
cannot
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Electrical Conductivity

Electrical conductivity is only possible
when a compound contains charged
particles (i.e. an electrolyte)
◦ e.g. NaCl, NaNO3 are electrolytes

Since most organic compounds are
molecular, not ionic, it does not conduct
electricity.
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
1 M sucrose

1 M NaCl
+
Na

1 M ethanol

Cl
-
hexane
H
H3C
H3C
O
CH3
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Summary
Organic chemistry is the study of carbon
compounds.
 Organic compounds have the ff
properties:

◦
◦
◦
◦
Flammable
Combustible
Immiscble in polar solvents like water
Non-electrolytes; do not conduct electricity
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