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Module 1: Basic Concepts - Moles
Lesson Material- Calculators:
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Mole Calculator I
- Mole Calculator II
Objective
- Calculate the quantities of materials in terms of gram moles and pound moles.
The term moles is used to denote the number of molecules present. One gram mole (denoted "gm mole") is 6.023 
1023 molecules (Avogadro's Number). One pound mole is 453.6 times larger than a gram mole because 1 pound equals 453.6 grams.
Moles is a very important concept because it gives us a way to discuss the total number of molecules present to react with other molecules or to exert physical properties such as temperature and pressure. For example, the pressure of gas in a 100-liter container would double if the number of moles increased from 5 to 10 gram moles. As indicated by the chemical reaction below, one half of a gram mole of molecular oxygen is needed to react with one gram mole of carbon monoxide to produce carbon dioxide.
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The number of moles present can be calculated by dividing the total mass of the material by its molecular weight.
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For example, if there are 128 pounds of sulfur dioxide, there must be 2 pound moles since the molecular weight of sulfur dioxide is 64 (sulfur atomic weight = 32, oxygen atomic weight = 16).
Purpose: Mole Calculators I and II determine the quantity of gram moles and pound moles of a substance. Mole Calculator I can be used for a small set of compounds commonly encountered in the field of air pollution. This calculator requires you to select a compound from a "pick list." You do not need to know the molecular weights of these compounds. On the other hand, Mole Calculator II is more generic. It can be used to calculate the number of moles for all compounds and requires you to know the molecular weight of the compound.
Link to Appendix E (Periodic Table of Elements).
Notes:
- These Java applets may take a few minutes to load.
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Sometimes calculator output is provided in an exponential format in base ten as shown below.
5.2e003 = 5.2
103
5.2e-003 = 5.2 10-3
- Inputting non-numeric characters such as commas and percent signs will result in erroneous output. (Decimal points are fine to use.)
Practice Problems
Moles
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Instructions:
- Complete the Practice Problems before proceeding to the next lesson. Click on the button below.