1. Chemical Reactions

2. Chemical Reactions
New Substances produced by changing the way atoms are arranged
Physical Changes ≠ Chemical Reaction
Evidence
Change in Color (rust)
Temperature Change (endo/exo-thermic)
Formation of a Gas
Formation of a Solid (Precipitate)

3. Chemical Equation
Uses chemical formulas and symbols to describe a chemical reaction and the product it produces (see below)
Symbol
Meaning
Produces or Yields
(aq)
Aqueous +
Plus
Heat
Reactants heated
(s)
Solid
Light
Reactants exposed to light
(l)
Liquid
Elec
Electric current applied to reactants
(g)
Gas

4. Reactants: Substances Present @ Beginning
Products: Substances Formed by the Reaction
Yields: An “equal sign” in a chemical reaction meaning “produces”, “creates”, or “forms”…
Na Cl2  NaCl
Reactants Yields Products

5. Reaction Classifications

6. A new compound is formed by combining simpler reactants
Synthesis
…Combining Elements…
A new compound is formed by combining simpler reactants
A + B  AB
Mg + O2  MgO

7. Decomposition CD  C + D H2O  H2 + O2 …Separating Elements…
A reactant breaks down into simpler products (opposite of synthesis)
CD  C + D
H2O  H2 + O2

8. …FIRE! (Needs Oxygen and produces CO2 )…
Combustion
…FIRE! (Needs Oxygen and produces CO2 )…
EF + O2  H2O + CO2
CH4 + O2  H2O + CO2

9. Single Replacement
…Switch out ONE element with another in a compound!... GH + I  GI + H CuCl2 + Zn  ZnCl2 + Cu

10. …Switch Out Two Elements with Two Others!...
Double Replacement
…Switch Out Two Elements with Two Others!...
JK + LM  JM + KL
AgNO3 + HCl  AgCl + HNO3

11. Rate of Reaction Concentration Surface Area Temperature
High Concentration = faster reaction
Surface Area
More surfaces available to react = faster reaction
Temperature
Higher Temperatures = faster reaction
Particles speed up or slow down…speeding up or slowing down the reaction…

12. Rate of Reaction (Cont’d)
Catalyst
Something that speeds up the rate of reaction without being affected itself.
Inhibitor
Something that slows down the rate of reaction without being affected itself.
(Stop Here)

13. The Law of Conservation of Mass
Matter Can Neither Be Created Nor Destroyed
Reactants and Products MUST be EQUAL!
So…
We Balance Chemical Equations!

14. Videos! Alkali Metals in Water (3 min) Sodium in Water (1 min)
Francium Bomb in Ocean (30 sec)
Chemistry Explosions (13 min)