1. 14:1 Forming New Substances
Chemical Reactions
14:1 Forming New Substances

2. Terms
Chemical reaction Chemical formula Chemical equation Reactants Products Law of conservation of mass

3. Clues to Chemical Reactions
Gas formation
Look for bubbles
Solid formation
Precipitate: a solid formed in a solution
Color change
Energy change
Release or absorption of energy

4. Breaking and Making Bonds
Reaction of Hydrogen and Chlorine

5. Chemical Formulas Tells how many of each atom is in a molecule H2O
C6H12O6
C14H9Cl5
C3H5N3O9
C3H8O

6. Chemical Formulas
Atoms in parentheses: multiply everything inside the parentheses by the subscript number.
Ca(NO3)2
Mg(OH)2
Al2(SO4)3

7. Chemical Equations Reactants yield product
Atoms are not lost or gained
Number of atoms in the reactants is equal to the number of atoms in the products
Law of conservation of mass is the reason

8. Chemical Equations

9. Types of Chemical Reactions

10. Synthesis Reactions
Reaction in which two or more substances combine to form a single compound

11. Decomposition Reactions
Reaction in which a single compound breaks down to form two or more simpler substances

12. Single Replacement Reactions
Reaction in which an element takes the place of another element that is part of a compound.

13. Double Replacement Reactions
Reaction in which ions in two compounds switch places

14. Energy and Rates of Chemical Reactions

15. Every Reaction Involves Energy
Exothermic-Energy is released (gives energy to the surroundings)
“exo”- exit
“thermic”- heat or energy
Light energy is released in glow sticks
Light and thermal energy released in campfire

16. Every Reaction Involves Energy
Endothermic-Energy is absorbed
“endo”- go in
“thermic”- heat or energy
Activation Energy
Minimum amount of energy
needed for substances to react

17. Every Reaction Involves Energy

18. Factors Affecting Rates of Reactions
Temperature
Increase in temperature increase in rate of reaction
Concentration (density)-amount of one substance dissolved in another
Increase in concentration increase in rate of reaction
Surface Area
Increase in surface area increase in rate of reaction
Catalysts and Inhibitors
Catalyst- substance that speeds up rate of reaction without being permanently changed (enzymes in body)
Inhibitor-substance that slows down or stops a chemical reaction (food preservatives)