Chemical Reactions

Reactants

are substances that undergo a chemical reaction.

Products

are substances that are formed in a chemical reaction.

Equations

communicate what is occurring in the reaction. They come in a variety of forms.

Word Equations

Only the chemical names of the reactants and products are shown.

The reactants are written on the left side of the arrow and the products are written on the right side.

Skeleton Equations

The symbols that represent the number and type of atoms for each compound are shown.

The subscripted letters indicate the state of the substance

(s)

Solid

(l)

Liquid

(g)

Gas

(aq)

Aqueous (in water)

Balanced Chemical Equations

Balanced chemical equations reflect the law of conservation of mass

Law of Conservation of Mass

# of atoms in reactants = # atoms in products

MINOH

M - metal

I - ions (polyatomic)

N - non-metals

O - oxygen

H - hydrogen

Synthesis Reactions

occur when two or more simple substances (often elements) combine to form a single, more complex product.

Binary compound

Two elements

Univalent metal and a non-metal

Form an ionic compound

(Ionic compounds are solids)

Multivalent metal and non-metal

Fork various compounds

Two non-metals

Form a covalent compound

(Told the product)

Element and a compound

Form new compound

(told the product)

Two compounds

Form a new compound

Non-metal oxide and water

Form an acid

Metal oxide and water

Form a base

Decomposition reaction

Occurs when a compound breaks down to form two or more elements or simpler compounds. It is the reverse of a synthesis reaction

Binary compound

Decomposes into its elements

Often times electrolysis is used to break apart the compound

Carbonates

Decompose into metal oxides and carbon dioxide

Metal hydroxides

Decompose into a metal and water

Metal nitrate

Decomposes into a metal nitrite and oxygen gas

Combustion Reaction

Oxygen combines with another substance to release energy in the form of heat and light, as well as producing one or more oxides

Complete combustion of hydrocarbons

Hydrocarbons are compounds composed on of the elements hydrogen and carbon.

When these undergo combustion reactions they produce carbon dioxide and water.

Incomplete combustion of hydrocarbons

This occurs when not enough oxygen is present to react with the hydrocarbon. Often you will see a nice yellow flame! But in addition to carbon dioxide and water vapour, soot (elemental carbon) and carbon monoxide are produced.