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What is a Chemical Reaction? One or more substances undergoes change to produce one or more different substances!

One or more substances undergoes change to produce one or more different substances!

Evidence of Change?

Reading a Reaction… Zn + I 2 ZnI 2 ZnI 2 REACTANTS PRODUCTS

What’s the point? The charcoal used in a grill is basically solid carbon. The carbon reacts with oxygen in its gaseous state to yield a product called carbon dioxide. C (s) + O 2 (g) ---> CO 2 (g)

A Chemical Reaction Depicts the kind of reactants and products and their relative amounts in a reaction. 4 Al (s) + 3 O 2 (g) ---> 2 Al 2 O 3 (s )

Reading a Chemical Equation 4 Al (s) + 3 O 2 (g) ---> 2 Al 2 O 3 (s ) Reactants Subscripts Product Coeffecients State of matter Yields

Subscripts vs. Coefficients subscripts = number of atoms of a element in a compound.subscripts = number of atoms of a element in a compound. The coefficient = the number, of molecules of the compound.The coefficient = the number, of molecules of the compound.

Subscripts vs. Coefficients 2 CO CO 2

CH O 2 ===> CO H 2 O

Counting Atoms… Mg(OH) 2 3 Mg(OH) 2

Law of Conservation of Mass

Rules For Balancing… –you may add coefficients in front of the compounds to balance the reaction, not –but you may not change the subscripts.

Balancing Equations ___ H 2 (g) + ___ O 2 (g) ---> ___ H 2 O(l) 22

H 2 + Cl 2 --> 2 HCl

Balancing Equations ___ Al(s) + ___ Br 2 (l) ---> ___ Al 2 Br 6 (s) 23

Types: Synthesis Example C + O 2 OO C +  OO C OO C OO C O O C O O C O O C O O C O O C O O C O O C O O C O O C O O C O O C O O C General: A + B  AB

Types: Decomposition Example: NaCl General: AB  A + B  Cl Na Cl + Na

Types: Decomposition Example 2HgO  O Hg O OO + General: AB  A + B

Types: Single displacement Example: Zn + CuCl 2  Zn Cl Cu + General: AB + C  AC + B Cl Zn Cu +

Types: Double displacement Example: MgO + CaS General:AB + CD  AD + CB S O  Mg Ca + O S Mg Ca +

What kind of reaction?

Hints…. Test #1: –Zinc size –Add a catalyst Test # 5 –Gently shake the test tube Think about your results!