1. Ch 8 Chem Equations and Reactions 8.1 Describing Chemical Reactions
Physical Indicators
Release heat/light
Color change
Production of a gas
Formation of a precipitate (solid)
Odor
Law of Conservation of Mass
Known facts
Correct formula (reactantsproducts)
Coefficients show mass same

2. Word Equations Formula Equations Balanced Equations
Reactants and products represented with words
Formula Equations
Using symbols and formulas for reactants and products
Subscripts to have neutral compounds
Not balanced yet
Balanced Equations
Coefficients before formulas to follow law of conservation of mass

3. Important Symbols for writing chemical equations

4. Balancing Chemical Equations
Coefficients represent relative not absolute amounts of reactants and products
Relative masses of reactants and products can be determined from coefficients
Reverse reaction has same relative amounts as forward reaction
Balancing Chemical Equations
Identify names of reactants and products, write word equation
Write formula equation for reactants and products
Balance using law of conservation of mass
Count atoms on both sides to check its balanced

5. 8.2 Types of chemical reactions
Synthesis Reaction: 2 or more substances combine to make new compound
Oxygen and sulfur
Metals and Halogens
Oxides

6. Decomposition Reactions: single compound makes 2+ substances
Electrolysis: use electric current
Metal Carbonates
Metal Hydroxides
Metal Chlorates
Acids

7. Single-replacement: 1 element replaces similar element in the compound
Metals
Hydrogen in water with metal
Hydrogen in acid with metal
Halogens

8. Double-displacement: the ions of 2 compounds exchange places in aq soln to form new compounds
Form precipitate
Form gas
Form water

9. Combustion Reaction: substance combines with oxygen and releases large amount of light/heat

10. 8.3 Activity series of the elements
Activity series: organized according to ease element will undergo chemical reaction