1. 1 Chapter 5 Chemical Reactions and Quantities 5.1 Chemical Changes Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

2. 2 Learning Goals Identify a change in a substance as a chemical or a physical change. Write a balanced chemical equation from the formulas of the reactants and products for a reaction. Identify a reaction as a combination, decomposition, replacement, or combustion reaction. Define the terms oxidation and reduction. Use Avogadro’s number to determine the number of particles in a given number of moles. Determine the molar mass of a substance and use molar mass to convert between grams and moles. Given a quantity in moles of reactant or product, calculate the moles of another substance in the reaction. Given the mass in grams of a substance in a reaction, calculate the mass in grams of another substance in the reaction. Describe exothermic reactions and factors that affect the rate of a reaction.

3. 3 Physical Change In a physical change, the identity and composition of the substance do not change. the state can change or the material can be torn into smaller pieces. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

4. 4 Chemical Change In a chemical change, reacting substances form new substances with different compositions and properties. a chemical reaction takes place. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

5. 5 Some Examples of Chemical and Physical Changes

6. 6 Classify each of the following as a 1) physical change or 2) chemical change. A. ____Burning a candle. B. ____Ice melting on the street. C. ____Toasting a marshmallow. D. ____Cutting a pizza. E. ____Polishing a silver bowl. Learning Check

7. 7 Classify each of the following as a 1) physical change or 2) chemical change. A. 2 Burning a candle. B. 1 Ice melting on the street. C. 2 Toasting a marshmallow. D. 1 Cutting a pizza. E. 2 Polishing a silver bowl. Solution

8. 8 Chemical Reaction In a chemical reaction a chemical change produces one or more new substances. there is a change in the composition of one or more substances. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

9. 9 Chemical Reaction In a chemical reaction, old bonds are broken and new bonds are formed. atoms in the reactants are rearranged to form one or more different substances. Fe and O 2 form rust (Fe 2 O 3 ).