2/23/16
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EXPERIMENT 6 Chemistry 110 Lab
WRITING AND NAMING
CHEMICAL FORMULAS
PURPOSE: The purpose of this lab is to write the names and formulas of chemical
compounds so that eventually the students will be able to write complete balanced
chemical equations.
I. INTRODUCTION
So far you have learned what a chemical symbol is. For example, Pb is the symbol for the element
lead. Elements are not often found pure in nature. Most elements are chemically combined in a
definite ratio with other elements. These types of substances are called compounds. Most of the
earthโs hydrogen is not in the form H2, but is in water in the form H2O. Just as elements have
symbols, compounds have formulas. It is very important that a chemistry student learn how to
name formulas and learn to write the correct formula from a given name.
The elements in a compound are in a definite or set ratio. Water is always H2O, never anything
else. The ratio is always 2 hydrogens to 1 oxygen. This definite composition is what makes
compounds unique from mixtures. In experiment 5 you learned that a mixture of two substances
can be in any ratio or proportion.
Chemistry is largely about describing chemical reactions and predicting their results. In order to
correctly write a chemical equation we must first learn how to write and name chemical formulas.
For example, we may be given a reaction in sentence form: When aqueous silver nitrate reacts
with aqueous sodium chloride a precipitate silver chloride is formed and the sodium and nitrate
ions remain in solution. It is impractical to leave the reaction in sentence form. Chemists have a
short hand version that looks like this:
AgNO3 (aq)+ NaCl (aq) ! AgCl (s) + NaNO3 (aq)
Before we can successfully write a chemical equation, we must first learn how to write formulas
from the names of compounds and how to name formulas.
In this experiment you will:
Write the chemical formulas of given named compounds
Write the names of given compound formulas
