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TRANSCRIPT
Chemical Reactions and Equations
• Chemical Reactions are associated with chemical change.
• Whenever a chemical change occurs chemical reaction is said to take place.
• Chemical reactions are usually irreversible and a new product is formed.
Chemical Reactions
• There are five main signs that indicate a chemical reaction has taken place.
Signs of Chemical Reactions
Change in color
Evolution of gas Production of light Formation of a solid
Absorption or release of heat
• A chemical reaction is the conversion of one substance or set of substances into another.
• Any substance that we start with is a reactant.• A new substance that forms during the reaction is
a product.
methane + oxygen carbon dioxide + water
Reactant Product
Chemical Equations
• A chemical equation is a symbolic representation of a chemical reaction.
For example:
The reactants are written on the left side, and the products are written on the right side.
An arrow shows the direction of reaction.
Chemical Equations
• The equation must represent known facts
• The equation must contain the correct formulas for the reactants and products.
• The physical state—solid(s), liquid(l), gas(g), or aqueous solution(aq)--- is shown for each reactant and product.
• The equation must be balanced.
Characteristics of Chemical Reaction
• The number of atoms of each element is the same in the products as in the reactants.
• For example:
Balanced Chemical equations
Four basic types of the chemical reactions
Types of the Chemical Reactions
• When a compound undergoes a decomposition reaction, it breaks down into the elements of which it is composed or into simpler compounds.
Decomposition Reaction
• In a combination reaction, two elements, an element and a compound, or two compounds react to produce a single compound.
Combination Reaction(Synthesis)
• In a single-displacement reaction, a free element displaces another element from a compound to produce a different compound and a different free element.
Single-displacement Reaction
• In each reaction, two compounds exchange parts to form two new compounds is called a double-displacement reaction.
Double-displacement Reaction
The End
Made by Yilin Yao(Tony)CHEM 105 11Sept 27,2016