General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 2.1 Energy Chapter 2 Energy and Matter © 2013 Pearson Education, Inc. Lectures

© 2013 Pearson Education, Inc. Chapter 2, Section 1 2 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 3 Potential Energy Examples:  water behind a dam  a compressed spring  chemical bonds in.gasoline, coal, or food Potential energy is the energy stored for use at a later time.

© 2013 Pearson Education, Inc. Chapter 2, Section 1 4 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 5 Learning Check Identify each of the following as potential energy or kinetic energy. A. roller blading B. a peanut butter and jelly sandwich C. mowing the lawn D. gasoline in the gas tank

© 2013 Pearson Education, Inc. Chapter 2, Section 1 6 Solution Identify each of the following as potential energy or kinetic energy. A. roller blading kinetic B. a peanut butter and jelly sandwich potential C. mowing the lawn kinetic D. gasoline in the gas tank potential

© 2013 Pearson Education, Inc. Chapter 2, Section 1 7 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 8 Heat is measured in joules or calories.   Units for Measuring Energy or Heat

© 2013 Pearson Education, Inc. Chapter 2, Section 1 9 Examples of Energy Values in Joules

© 2013 Pearson Education, Inc. Chapter 2, Section 1 10 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 11 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. Step 2 Write a plan to convert the given unit to the needed unit. GivenNeed 150 Jcalories energy factor Jcal

© 2013 Pearson Education, Inc. Chapter 2, Section 1 12 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