chApTer
1
organic Compounds
why Is Carbon So ubiquitous?
keY concepTs
After completing this chapter you will
be able to
•
describe some impacts of
organic compounds on human
health, society, and the
environment
•
use appropriate terminology,
including IUPAC nomenclature,
to describe organic compounds
and their reactions
•
safely perform laboratory
investigations involving organic
compounds
•
create molecular models to
represent simple organic
compounds and their reactions
•
compare the structural formulas
and properties of different
classes of organic compounds
•
explain the changes that occur
during various organic chemical
reactions and predict the
products of those reactions
•
explain the concept of isomerism
and relate variations in the
properties of isomers to their
structural formulas
As far as we know, life exists only on Earth. Why does life exist on Earth at
all? What enables it to exist? The availability of liquid water is essential for life.
Equally important are the elements carbon and nitrogen. Together, these elements form most of the thousands of compounds that make up living things.
According to Stephen Hawking, “What we normally think of as ‘life’ is based
on chains of carbon atoms, with a few other atoms, such as nitrogen or phosphorous. One can speculate that one might have life with some other chemical
basis . . . but carbon seems the most favourable case, because it has the richest
chemistry.”
Historically, the distinction between inorganic and organic substances was
based on whether a compound was produced by living things. Until the early
nineteenth century it was believed that organic compounds contained a “life
force” and could only be made by living organisms. In 1828, German chemist
Friedrich Wöhler (1800–1882) changed that belief: he successfully prepared
urea, a component of urine, from inorganic ammonium cyanate. This proved
that organic compounds can be made from inorganic materials.
The definition of organic chemistry has since changed. It is now the study
of carbon-containing compounds and their properties. There are a few carbon
compounds, including carbon oxides and carbonates, that we consider to
be inorganic. The vast majority of carbon-containing compounds, however,
contain chains or rings of carbon atoms and are considered to be organic
compounds. Why can carbon atoms form long chains, rings, and double and
triple bonds when other elements cannot? Each atom of carbon has the ability
to form four stable covalent bonds resulting in molecules with a variety of
unique shapes and sizes. Organic molecules may contain one carbon atom
or tens of thousands of carbon atoms, or any number in between. Many
carbon-based molecules are involved in complex tasks of life. DNA, a large
biological molecule found in plant and animal cells, stores genetic information. Organic molecules in plant chloroplasts transform light energy from the
Sun into chemical energy during photosynthesis. Fatty acids are long-chained
carbon molecules that make up cell membranes.
In this chapter we will explore how carbon atoms bond to each other and
to other atoms to form the molecules that enable life to exist on our planet.
STARTiNg PoINTS
Answer the following questions using your current
knowledge. You will have a chance to revisit these questions
later, applying concepts and skills from the chapter.
1. What does the term “organic” mean in everyday language?
How does this definition relate to “organic chemistry”?
2. Consider the physical and bonding properties of
carbon. What other element(s) on the periodic table
demonstrate(s) similar properties? Justify your answer.
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Chapter 1 • Organic Compounds
7924_Chem_CH01.indd 6
3. Many organic compounds used in everyday applications
are extracted from natural sources. Give two examples of
such compounds.
4. In addition to carbon, what other elements are
commonly found in organic compounds? How do these
elements affect the properties of organic compounds?
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5/3/12 1:39 PM
Mini Investigation
An Enlightening organic Compound (Teacher demonstration)
SKILLS
HANDBOOK
Skills: Questioning, Observing, Evaluating
In this demonstration you will observe an unusual reaction in
which luminol, an organic compound, reacts to produce a new
substance that emits light. The glow of fireflies at night comes
from a similar reaction.
Equipment and Materials: chemical safety goggles; lab apron;
two 1 L Erlenmeyer flasks; retort stand and ring clamp; funnel;
3 utility clamps; 1 m length of clear plastic tubing; distilled water;
Solution A (2.0 g sodium carbonate, Na2CO3(s); 0.1 g luminol,
C8H7O2N3(s); 12.0 g sodium bicarbonate, NaHCO3(s); 0.25 g
ammonium carbonate monohydrate, (NH4)2CO
0.2 g SM.ai
WHIMIS
Corrosive
3·H2O(s);
copper(II) sulfate pentahydrate, CuSO4·5H2O(s)); Solution B
WHIMIS Corrosive
.aihydrogen peroxide, H2O2(aq))
(25 mL 3 %
Copper(II) sulfate pentahydrate is toxic and an irritant. Avoid
skin and eye contact. In the case of contact, wash the
affected area with lots of cool water and inform your teacher.
1. Put on your safety goggles and apron.
2. Dissolve the first two ingredients for Solution A in a
1 L flask containing 250 mL of distilled water.
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7924_Chem_CH01.indd 7
A1, A2.3
3. Dissolve the remaining ingredients for Solution A in the flask.
4. Dilute Solution A to 500 mL by adding distilled water.
5. Prepare Solution B by diluting 25 mL of 3% hydrogen
peroxide to 500 mL with distilled water.
6. Attach a 1 m coil of clear plastic tubing to a retort pole
with clamps.
7. Place a funnel in a ring clamp attached high on the retort
pole. Place the lower end of the tubing in the second
Erlenmeyer flask.
8. Dim the room lights.
9. Slowly pour Solution A and Solution B into funnel.
A. During this reaction, luminol is changed into an ion called
aminophthalate. Which entity has more chemical energy
associated with its structure: luminol or aminophthalate?
How can you tell? T/I
B. Suggest applications for this reaction.
A
introduction
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5/3/12 1:39 PM