CHEMISTRY: The Laws Governing Formulas and Names

What four guidelines should you follow to write the formula of a chemical compound?

1. *An* -ide *ending generally indicates a binary compound.* 2. *An* -ite or -ate *ending means a polyatomic ion that includes 3. oxygen is in the formula.* 4. *Prefixes in a name generally indicate that the compound is molecular.* 5. *A Roman numeral after the name of a cation shows the ionic charge of the cation.*

How do you use a flowchart to write the name of a chemical compound?

Follow the arrows and answer the questions on the flowchart to write the correct name for a compound.

HNO3

Nitric Acid

QxRy

Q and R can be atoms, monatomic ions, or polyatomic ions.

Ratios of atoms can also be expressed as ratios of masses.

Ratios of atoms can also be expressed as ratios of masses.

What are the two laws that describe how compounds form?

These ways are summed up in two laws: the law of definite proportions and the law of multiple proportions.

law of definite proportions

in samples of any chemical compound, the masses of the elements are always in the same proportion

law of multiple proportions

whenever two elements form more than one compound, the different masses of one element that combine with the same mass of the other element are in the ratio of small whole numbers