Chemistry 11 Unit 11
I.
Introduction:
• Organic chemistry is the chemistry of
CARBON compounds.
• The name “organic” refers to how many of
these compounds are derived from living
things, “organisms”.
• However, many organic compounds are
synthetically produced.
•
•
•
•
•
•
Plastics
Synthetic fibres
(& natural)
Dyes & drugs
Petroleum products
Flavouring agents
& many others
• There are over 8 million known organic
compounds
• Organic compounds are composed of
COVALENT bonds.
• Other elements often found in organic
compounds include:
•
•
•
•
•
•
•
•
H
O
N
P
S
Cl
Other halogens
Etc.
II. Carbon Bonding:
• Carbon atoms have 4 valence electrons and can
form 4 bonds with up to 4 other atoms.
C
+
4H
H
H C H
H
• How many bonds can O & N form?
O
+
2H
N
+
3H
O H
H
H N H
H
Draw electron dot diagrams for the following:
C2H6
C2H4
C2H2
ethane
ethene
ethyne
H H
H C C H
H H
H
H
C C
H
H
H C C H
H H
H C C H
H H
H
H
C C
H
H
H C C H
III. Empirical, Molecular & Structural Formula
• Empirical formula shows the smallest whole number
ratio of atoms in a molecule.
• Molecular formula shows the actual number of each
atom in a molecule.
• Structural formula shows the relative positions of
each atom in a molecule.
ethane
ethene
ethyne
Empirical
CH3
CH2
CH
Molecular
C2H6
C2H4
C2H2
Structural
CH3CH3
CH2CH2
CHCH
H H
H C C H
H H
H
H
C C
H
H
H C C H
IV. Formula Calculations:
1. A charcoal briquette is composed of 43.2g of carbon. When it is
burned it combines with oxygen to form a compound with a mass of
159.0g. What is the empirical formula of the resulting compound?
mass of C = 43.2g
moles of C = 43.2g 1mol = 3.60mol
12g
mass of O = 159.0 - 43.2
moles of O = 115.8g 1mol = 7.24mol
= 115.8g
16g
Empirical Formula = CO2
Ratio of C to O = 1 : 2
2. A 10.00 g sample of a compound is composed of 8.00g of carbon and
2.00g of hydrogen. The molar mass of the compound is 30g. What
is the empirical and molecular formula of the compound?
moles of C = 8.00g 1mol = 0.667mol 1
12g
Empirical Formula = CH3
moles of H = 2.00g 1mol = 2.0mol
3
1.0g
15 x 2 = 30 Empirical
Molar mass of compound = 30g/mol
formula must be doubled.
Molar mass of empirical formula = 15g/mol
Molecular Formula = C2H6