Ratios and Stoichiometry in Chemistry

Stoichiometry is a vital skill for any chemist who performs real chemical reactions. As such it is important to be able to do stoichiometry in both general and organic chemistry. It relates the relative quantities of every component of the chemical reaction. This helps to predict how much product you can get out of a certain reaction, how much starting materials you might have left over, or what exact ratio of reactant you need to put into the reaction. You can think about stoichiometry in chemistry like as if it is a recipe in a cookbook.

Some of the chemicals used in reactions can be incredibly expensive for instance, osmium tetroxide (OsO4)  that is used in industry and academic research to oxidize alkenes costs upwards of $500 per gram! Other chemicals are so abundant the chemist need not worry about their ability to access them, such as oxygen or water. Stoichiometry uses a balanced chemical equation, a periodic table, and analytical balances to ensure chemists always gets the desired amount of product while not wasting a precious reagent unnecessarily.

The essential skill of using the stoichiometry boils down to two essential points. First, setting up and balancing the chemical equation. And second, to use the balanced equation to perform stoichiometric calculations. These calculations usually involve converting the masses, volumes, and concentrations to moles of reactants and using the simple ratios, calculating the expected amounts of products or other reagents.

This tutorial will be broken into four sections. The first part will cover the math skills required to appropriately use ratios to perform unit conversions.  The second will cover how to read a chemical equation.  The third section will cover moles and molarity. And the fourth will combine all the information and the techniques for solving stoichiometric problems and provide some examples.

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