Moles, % Composition, Empirical and Molecular Formulas

Dimensional Analysis: How to convert in Chemistry.

Moles, % Composition, Empirical and Molecular Formulas

Learning Target 2.4.1: I can determine the molar mass of a compound from its chemical formula and a table of atomic masses; convert the mass of a molecular substance to moles, number of particles, or volume of gas at standard temperature and pressure.

Dimensional Analysis: How to convert in Chemistry.

Goal 2.4.1.b: I can use dimensional analysis to convert from one unit to another.

Dimensional Analysis, also known as factor/label method, is mathematical method that converts from one unit to another. In math you learned that when you do the following calculation with a fraction that your numerator “2” in and denominator “2” in canceled because they are the same:

In a calculation, when units in the numerator and denominator are common, they cancel. Understanding this concept is important and is the underlying principle of Dimensional Analysis. In chemistry, Dimensional Analysis is used to convert from amount of one substance to another. The specific term is called Stoichiometry. You will learn more about Stoichiometry later, however, you will need to learn the begining part of Stoichiometry which is converting between amount of material to the mole.

Watch the tutorial from ChemCollective Dimensional Analysis^[1]. Complete the quiz after the embedded movie.

List the steps to convert from moles of water to molecules of water using dimensional analysis. If you are in a classroom, turn to your neighbor and discuss what you have written.

Practice by doing the Dimensional Analysis worksheet. Then go back to the ChemCollective and complete the Dimensional Analysis quiz.