Honors Chemistry Unit 6 Balancing and Types of Chemical Reactions

Chemical Reactions

• statement that uses chemical formulas to show identities and relative amounts of substances involved in a chemical change(change reactants to make products)

Reactants →

Products

Exothermic Chemical Reaction

• releases energy

• has energy/heat as a product

Endothermic Chemical Reaction

• absorbs energy

• has energy/heat as a reactant

Law of Conservation of Mass and Energy

matter and energy is neither created nor destroyed in a chemical reaction

Subscripts

• the small numbers that appear after some symbols in a formula

• apply only to the symbol they are after

• can be distributed through multiplication if placed outside a parentheses

Coefficients

• the large numbers that appear in front of a formula used to represent more than one of the same molecule

• apply to all symbols that appear after it in the formula

A Hydrocarbon reaction means to balance the equation..

put a 2(equation)

Steps to Balance Chemical Reactions

1. count the number of each molecule/element you have

2. do what you can to make each molecule/element the same on each side through changing coefficients

3. if an element is going to be odd, change it to be equal and then proceed

Balance this equation:

_C6H14+_O2→_CO2+_H2O

2C6H14+19O2→12CO2+14H2O

Balance this equation:

_C5H8(OH)2+_O2→_CO2+_H2O

2C5H8(OH)2+13O2→10CO2+10H2O

Synthesis Reaction

• 2 or more substances combine to form a single product

• A+B→AB

• How to recognize? 1 product

Decomposition Reaction

• single compound breaks down to form two or more products(elements or compounds)

• BC→B+C

• How to recognize? 1 reactant

Single Replacement Reaction

• the atoms of one element will replace the atoms of another element in a compound

• A+BC→AC+B

• How to recognize? An element and compound react

Double Replacement Reaction

• involves the exchange of ions between two compounds

• AB+CD→CB+AD

• How to recognize? Two compounds make two compounds

Combustion Reactions

• oxygen reacts with a substance to release energy in the form of heat and light

• How to recognize? Reactant has Hydrocarbon

Complete Combustion

reaction of a hydrocarbon and oxygen that yield carbon dioxide

Incomplete Combustion

reaction of a hydrocarbon and oxygen that yields carbon monoxide