2.1 Science and Technology in Society 2.2 Changes in Matter 2.3 Balancing Chemical Reactions
(2.3) TYPES OF CHEMICAL REACTIONS
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Transcript of (2.3) TYPES OF CHEMICAL REACTIONS
(2.3) TYPES OF CHEMICAL REACTIONS
(p144-147)
Chemical Reaction
Reactants- the starting materials in a reaction.
Products- the new materials formed in a reaction.
Chemical Equation
Describes a chemical reaction
reactants products
Note: The symbol () can be read as yields or forms or produces
Chemical Reactions – 4 Types
4 main types of chemical reactions Synthesis Decomposition Single displacement Double displacement
1. Synthesis Reactions
Two or more reactants combine to form a new product.
GENERAL CHEMICAL EQUATION (GCE)
Synthesis Reactions-Examples
sodium + oxygen sodium oxide
2 H2 + O2 2 H2O
2. Decomposition Reactions
A compound is broken down into elements or smaller compounds.
GENERAL CHEMICAL EQUATION (GCE)
Decomposition Reactions-Examples
sodium oxide sodium + oxygen
2 H2O 2 H2 + O2
3. Single Displacement Reactions
One element replaces another element to form a new compound.
GENERAL CHEMICAL EQUATION (GCE)
Or
Single Displacement- Examples
calcium + hydrogen bromide calcium bromide + hydrogen
Br2 + 2 KI + 2 KBr + I2
4. Double Displacement Reactions
In a double displacement reaction the metal ions in two compounds switch places…”partner swap”
GENERAL CHEMICAL EQUATION (GCE)
Double Displacement- Examples
barium sulfide + potassium iodide barium iodide + potassium sulfide
AgNO3 + KCl AgCl + KNO3
Chemical Reactions – 5th Type
Another reaction type is Combustion (also called burning)
The burning of fossil fuels always needs oxygen and will yield predictable products.
Complete combustion: lots of O2
Fuel + oxygen carbon dioxide + water(in general) CxHy + O2 CO2 + H2O CH4 + 2 O2 CO2 + 2 H2O
5. Combustion Reactions
The burning of fossil fuels always requires oxygen and will yield predictable products.
Complete combustion: lots of O2
Fuel + oxygen carbon dioxide + water
CxHy + O2 CO2 + H2OCH4 + 2 O2 CO2 + 2 H2O
Combustion Continued
Incomplete combustion: occurs when there is not enough O2
The products are different than with complete combustion.
CxHy + O2 C + CO + CO2 + H2O
CLASSWORK
“The Four Main Types of Chemical Reactions” handout