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General, Organic, and
Biological Chemistry
Fourth Edition
Karen Timberlake
Chapter 2
Energy and Matter
2.1
Energy
© 2013 Pearson Education, Inc.
Lectures
Energy
Energy
 is the ability to do work.
 can be classified as either
potential or kinetic.
 comes from the food we
eat and enables us to do
work.
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
2
Potential Energy
Potential energy is the
energy stored for use at a
later time.
Examples:
 water behind a dam
 a compressed spring
 chemical bonds in
.gasoline, coal, or food
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
3
Kinetic Energy
Kinetic energy is the
energy of matter in motion.
Examples:
 swimming
 water flowing over a dam
 working out
 burning gasoline
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
4
Learning Check
Identify each of the following as potential energy or
kinetic energy.
A.
B.
C.
D.
roller blading
a peanut butter and jelly sandwich
mowing the lawn
gasoline in the gas tank
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
5
Solution
Identify each of the following as potential energy or
kinetic energy.
A.
B.
C.
D.
roller blading
a peanut butter and jelly sandwich
mowing the lawn
gasoline in the gas tank
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
kinetic
potential
kinetic
potential
6
Heat and Energy
Heat
 is also called thermal energy.
 is associated with the motion of particles.
Adding heat to food increases the motion of the
particles, which makes the food hot.
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
7
Units for Measuring Energy or
Heat
Heat is measured in joules or calories.



© 2013 Pearson Education, Inc.
Chapter 2, Section 1
8
Examples of Energy Values in
Joules
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
9
Learning Check
How many calories are obtained from a pat of butter
if it provides 150 J of energy when metabolized?
A. 36 cal
B. 150 cal
C. 630 cal
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
10
Solution
How many calories are obtained from a pat of butter
if it provides 150 J of energy when metabolized?
Step 1 State the given and needed quantities.
Analyze the Problem.
Given
150 J
Need
calories
Step 2 Write a plan to convert the given unit to
the needed unit.
energy
J
cal
factor
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
11
Solution
How many calories are obtained from a pat of butter
if it provides 150 J of energy when metabolized?
Step 3 State the equalities and conversion
factors.
Step 4 Set up the problem to calculate the needed
quantity.
Answer: A
© 2013 Pearson Education, Inc.
Chapter 2, Section 1
12