General organic and biological chemistry structures off life 5th CH12 organic compounds GOB structures 5th ed

Lecture Presentation

Chapter 12

Organic Compounds

Karen C. Timberlake

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chapter 3 Introduction to Organic Chemistry: Hydrocarbons

Firefighters/emergency medical technicians are first responders
to fires, accidents, and other emergency situations.

They are required to have an emergency medical technician
certification in order to be able to treat seriously injured people.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Chapter 12 Readiness

Core Chemistry Skills

•
•
•

Drawing Lewis Structures (6.6)
Predicting Shape (6.8)
Balancing a Chemical Equation (7.1)

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


12.1 Organic Compounds

Organic chemistry is the study of carbon
compounds.

Organic compounds such
as vegetable oil contain carbon and hydrogen
and are not soluble in water.

Learning Goal Identify properties characteristic of organic or
inorganic compounds.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

Organic Compounds

An organic compound

•
•
•

Always contains carbon and hydrogen atoms.
May also contain other nonmetals such as oxygen, sulfur, nitrogen, phosphorus, or a halogen.
is often found in common products such as gasoline, medicines, shampoos, plastics, and
perfumes.

We organize organic compounds by their functional groups, which are groups of atoms bonded in a
specific way. Compounds that contain the same functional group have similar physical and chemical
properties.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Properties of Organic Compounds

Organic compounds typically

•

•
•

Have covalent bonds.
have low melting and boiling points.
are flammable and
undergo combustion.

•

are not soluble in water.

Vegetable oil is a mixture of organic compounds
and is not soluble in water.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Organic and Inorganic Compounds

Many inorganic compounds have
high melting and boiling points.

Inorganic compounds that are ionic
are usually soluble in water, and
most do not burn in air.

Propane, C3H8, is an organic compound used as a fuel. NaCl,
+
−
salt, is an inorganic compound composed of Na and Cl ions.
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Properties of Organic and Inorganic Compounds

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Study Check

Identify each characteristic as most typical of compounds that are inorganic or organic.

A.

It has a high melting point.

B.

It is not soluble in water.

C. It contains carbon and hydrogen atoms.
D. It has the formula MgCl2.

E.

It burns easily in air.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Solution

Identify each characteristic as most typical of compounds that are inorganic or organic.

A.

It has a high melting point.

inorganic

B.

It is not soluble in water.

organic

C. It contains carbon and hydrogen atoms.

D. It has the formula MgCl2.
E.

It burns easily in air.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

organic
inorganic
organic

© 2016 Pearson Education, Inc.


Representations of Organic Compounds

Hydrocarbons are organic compounds that contain only carbon and hydrogen.

•

In organic molecules, every carbon has four bonds.

•

In methane (CH4), the carbon atom forms an octet by sharing its four valence electrons with four
hydrogen atoms.

Three-dimensional and two-dimensional representations of methane: (a) space-filling model, (b) ball-andstick model, (c) wedge–dash model, (d) expanded structural formula, and (e) condensed structural formula.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Carbon Compounds: Methane (CH4)

Structures are most often represented using their corresponding two-dimensional
formulas.

•

The expanded structural formula shows all of the atoms and the bonds connected to
each atom.

•

A condensed structural formula
shows the carbon atoms each
grouped with the attached number
of hydrogen atoms.

CH4

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

Carbon Compounds: Methane (CH4)

In methane (CH4), carbon forms four covalent bonds to hydrogen. Methane is tetrahedral and has bond
angles
of 109°.

A hydrocarbon is referred to as a saturated hydrocarbon when all the bonds in the molecule are single
bonds.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Carbon Compounds: Ethane (C2H6)

In ethane (C2H6), each tetrahedral carbon forms three covalent bonds to hydrogen and one to the other
carbon.

Three-dimensional and two-dimensional representations of ethane: (a) space-filling model,(b) ball-and-stick
model, (c) wedge–dash model, (d) expanded structural formula, and (e) condensed structural formula.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

Study Check

In the butane molecule (C4H10), predict the shape around each carbon atom.

H

H

H

H

H

C

C

C

C

H

H

H

H

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

H

© 2016 Pearson Education, Inc.


Solution

In the butane molecule (C4H10), predict the shape around each carbon atom.

H

H

H

H

H

C

C

C

C

H

H

H

H

H

Each carbon atom has four single covalent bonds and, therefore, a tetrahedral shape.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


12.2 Alkanes

A large number of carbon compounds are possible
because the covalent bonds between carbon atoms,
such as those in propane (C3H8), are very strong,
allowing carbon atoms to form long, stable chains

Learning Goal Write the IUPAC names and draw the condensed structural formulas and skeletal formulas
for alkanes and cycloalkanes.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Alkanes

Alkanes

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•
•
•

are formed by a continuous chain of carbon atoms.
are named using the IUPAC (International Union of Pure and Applied Chemistry) system.
have names that end in ane.
use Greek prefixes to name carbon chains with five or more carbon atoms.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

IUPAC Names of Alkanes

Alkanes with five or more carbon atoms in a chain are named using Greek prefixes: pent (5), hex (6),
hept (7),
oct (8), non (9), and dec (10).

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Condensed Structural Formulas

In a condensed structural formula,

•
•

each carbon atom and its attached hydrogen atoms are written as a group.
a subscript indicates the number of hydrogen atoms bonded to each carbon atom.

Core Chemistry Skill Naming and Drawing Alkanes
General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Line-Angle Structural Formulas

A simplified structure of organic molecules

•
•

is called the line-angle structural formula.
shows a zigzag line in which carbon atoms are represented as the ends of each line and as corners.

Carbon atoms

•
•

at the end are bonded to three hydrogen atoms.
in the middle are bonded to two hydrogen atoms.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Guide to Drawing Structural Formulas for Alkanes

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.

Drawing Expanded, Condensed, and Line-Angle Structural Formulas

Draw the expanded, condensed, and line-angle structural formula for pentane.
STEP 1

Draw the carbon chain. A molecule of pentane has

five carbon atoms in a continuous

chain.

STEP 2

Draw the expanded structural formula by

adding the hydrogen atoms, using single

bonds to each of the carbon atoms.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.


Drawing Expanded, Condensed, and Line-Angle Structural Formulas

Draw the expanded, condensed, and line-angle structural formula for pentane.

STEP 3

Draw the condensed structural formula by

combining the H atoms with each C atom.

General, Organic, and Biological Chemistry: Structures of Life, 5/e
Karen C. Timberlake

© 2016 Pearson Education, Inc.