Section 2

Chemical Formulas and Equations

Identify each compound as ionic or covalent

Use the table 1 on page 297 to write the chemical formula

Sulfur trioxide

Calcium fluoride

Phosphorus pentachloride

Dinitrogen trioxide

Lithium oxide

Chemical Formulas• A shorthand way to use chemical symbols and numbers to represent substances

• Formed from the periodic table

Chemical Equations• Uses chemical symbols and formulas to describe a chemical reaction

The Process• Reactants-the starting materials

• Products-substances formed from reaction

• Yield- the arrow separates the two

Balancing Equations• Closed systems-nothing comes in or goes out

• Total mass of the system remains the same

Conservation of Matter

• Antoine Lavoisier• Mass is neither created

nor destroyed • Mass of the reactants

equals the mass of the products

Making Sense• Coefficient-number

placed in front of a chemical symbol or formula

• Only the coefficient can be changed not the subscript

Keep it Balanced• The number of atoms of the reactants must equal the number of atoms of the products

• You’ve done it!

Covalent Compounds• Composed of two nonmetals

• Prefixes used to express number of atoms of each element

Ionic Compounds• Composed of a metal and a nonmetal

• The compounds charges must equal 0

Be Accurate• Accuracy would result in the correct reaction or a big mistake

• Balance it out…..