1. Chapter 10
Chemical Reactions

2. Reactions and Equations
Section 10.1
Reactions and Equations

3. Section 10.1 Objectives Recognize evidence of chemical change
Represent chemical reactions with equations

4. Key Terms Chemical reaction Reactant Product Chemical equations
coefficient

5. Chemical Reactions
Atoms of one or more substances are rearranged to form different substances
Another name= chemical change
Important part of everyday life

6. Evidence of a Reaction
How to tell if a chemical reaction has taken place
Temperature change
Color change
Odor
Gas bubbles

7. Representing Chemical Reactions
Reactants: the starting substances
Products: resulting or ending substances
Arrow: “react to produce” or “yield”
Reactant 1 + reactant 2  product 1 + product 2

8. Symbols used in Equations
Table 10.1 on page 278
Why do these symbols mean?
(g) 
(s)
(aq) +
(l)

9. Physical States
Must know the state of reactant and products in order to determine if reaction will occur

10. Types of Equations
Three types of equations
Word
Skeleton
Chemical

11. Word Equations
Used to indicate the reactants and products of chemical reactions
Uses the actual names of the substances involved
Setup: Reactant 1 + Reactant 2  Product 1
Ex: Iron(s) + Chlorine(g)  Iron(III) Chloride(s)

12. Skeleton Equations
Uses chemical formulas to represent the substances unlike the word equation
Chemical formulas take the place of the words
Iron(s) + Chlorine(g)  Iron(III) Chloride(s) would become:
Fe(s) + Cl2(g)  Fe Cl3(s)

13. Practice Problems
Page 279

14. Chemical Equations Uses chemical formulas like the skeleton
Shows matter is conserved during a reaction (Law of Conservation of Mass)
Uses identities and relative amounts of the substances involved in a chemical reaction
Everything is balanced in a chemical equation

15. Balancing Chemical Equations
Find correct coefficients for chemical formulas
Coefficient is usually a whole number
1 is understood- not written

16. Steps to Balance a Chemical Equation
1: Write the skeleton equation
2: Count the atoms of elements in the reactants
3: Count the atoms of elements in the products
4:Change the coefficients to make both sides of the equation the equal
5:Write the coefficient(s) in the lowest ratio possible
6:Check your work
Ex:
2H2(g) + O2(g)  2H2O(g)

17. Practice Problems
Page 282

18. Homework
7-13 on page 283