Transcript Chemical Reactions

Chemical Reactions
Objectives


1) Write and balance equations
2) Identifying the types of reactions
Reactants and Products
Gallium + Sulfuric acid → Gallium Sulfate + Hydrogen
 Reactants- left side of the arrow
-starting materials
 Products-right side of the arrow
-the substance made, produced
 The number of atoms on the reactant side must equal
the number of atoms on the product side.
Balancing
Rules:
 1) Write the correct chemical formula for the reactants and the
products.
 2) Adjust the coefficients (the numbers that appear in front of
the formulas) only and evenly.
 3) Never change the subscripts (the small numbers in a formula)
 4) When counting atoms, multiply the coefficients by the
subscript for each element.
 5) There are seven elements, that when left alone, exist as
diatomic molecules.
Br2
I2
N2
Cl2
H2
O2
F2
Balancing Example

Ga + H2SO4 → Ga2(SO4)3 + H2
Balanced:
2Ga + 3H2SO4 → Ga2(SO4)3 + 3H2
Identifying Reactions

The five types of reactions:
-Synthesis or Combination
-Single Replacement
-Double Replacement
-Combustion
-Decomposition (6 types)
Synthesis

element + element → compound

Occurs when two or more elements are combined to form a
new substance
Also called Combination

Synthesis or Combination

Example:
2 Na + Cl2 → 2NaCl
Jayhawk says: Here’s an example of synthesis:
+
= Rivalry
Single Replacement

Occurs when one element displaces another in
a compound.
A
+ BC → B + AC
element + compound → element + compound
Single Replacement
Example:
Na + LiCl → NaCl + Li
Listen up ,class, it’s
time for an example.
Double Replacement

Occurs when the positive and negative ions of the two reactants are
interchanged

AB + CD → AD + CB

compound + compound→compound +compound

Never put two metals together
Double Replacement
Example:
2NaCl + Li2O → Na2O + 2LiCl
Did you know?
Double
replacement is
also referred to as
metathesis.
Combustion

Hydrocarbon + O2 → H2O + CO2
Combustion
Example:
C4H8 + O2 →H2O + CO2
Decomposition


Occurs when energy in the form of heat, light,
electricity, or mechanical shock is supplied. A
compound may decompose to form simpler
compounds and/or elements.
compound → 2 or more substances
→
Decomposition

There are 6 different types of decomposition
Did you know? You
might also know
decomposition by
analysis.
Electrical Decomposition
AB → A + B
2NaCl → 2Na + Cl2
Decomposition: Oxy-Acid
Oxy-Acid → Water + Nonmetal Oxide
H2SO4 → H2O + SO3
Examples:
HNO3
H3PO4
HClO2
Decomposition: Metallic Hydroxide
Metallic Hydroxide → Metal Oxide + Water
2LiOH → Li2O + H2O
Fe(OH)2 → FeO + H2O
Decomposition: Metallic Carbonate
Metallic Carbonate → Metal Oxide +Carbon Dioxide
MgCO3 → MgO + CO2
Fe2(CO3)2 → Fe2O3 + 3CO2
Decomposition: Metallic Chlorate
Metallic Chlorate → Metal Chloride + Oxygen
2LiClO2 → 2LiCl + 3O2
Ca(ClO3)2 → CaCl2 + 3O2
Decomposition: Metallic Oxide
Metallic Oxide → Metal + Oxygen
2Li2O → 4Li + O2
2BaO → 2Ba + O2
THE END