Equations

Chemical Reaction When a substance goes through a reaction and changes into another substance.

Chemical Equations A formula which shows how elements or compounds react to form new compounds

2H + + O -2  H 2 O

Parts of a chemical equations Reactants Yield Sign Products

Reactants The elements or compounds that are found on the left side of the yield sign

Yield Sign An arrow found in the equation which works like an equal sign

Products The elements or compounds that are found on the right side of the yield sign

Coefficient Is the number found in front of an ion or compound. It tells the number of that ion or compound you have

Balanced Equation For each element in a chemical equation, the same number of each element must be found on the left side of the arrow as on the right side

All chemical equations must be balanced.

To balance an equation, you can change the coefficient. However, you can never, never, never change the subscript.

Symbols used in Chemical Equations (l) The chemical is a liquid. (s) The chemical is a solid. (g) The chemical is a gas. (aq) The chemical is aqueous (dissolved in water).

Synthesis Reactions A reaction where the reactants combine to form a bigger compound (also known as combination)

Synthesis Reactions 2H + + O -2  H 2 O

Decomposition Reaction A reaction where the reactants break down (decompose)

Decomposition Reaction H 2 O  2H + + O -2

Single Displacement Reaction A reaction where one element replaces another element in a compound

Single Displacement Reaction 2Al Ag 2 S  Al 2 S 3 + 6Ag 2+

Double Displacement Reactions A reaction where the positive ion of two compounds switch, which forms two new compounds

Double Displacement Reactions HCl + NaOH  NaCl + H 2 O

Combustion A reaction in which a compound (often carbon) reacts with oxygen

Combustion C + O 2  CO 2 CH 4 + 2O 2  CO 2 + 2H 2 O C 3 H 8 + 5O 2  3CO 2 + 4H 2 O C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O

Redox Reactions A reaction where one compound loses electrons and becomes a smaller compound, while another compound gains electrons and becomes a bigger compound.

Redox Reactions C 6 H 12 O 6 + 6O 2  6CO 2 + 6H 2 O

Oxidized Compound The compound that loses electrons and becomes a smaller compound

Reduced Compound The compound that gains electrons and becomes a bigger compound

Oxidation-Reduction Reaction Another name for the Redox Reaction