The molecular weight is the mass of one mole of a substance. Usually, the units used for this are grams per mole. In this movie, we show how to calculate the molecular weight of a substance from the atomic weights given on the periodic table. On another page, we use the molecular weight to convert between the macroscopic scale (grams of a substance) and the microscopic scale (number of molecules of that substance).

Text version of this movie.

Element Atomic Weight (g/mol)

Ba 137.327

C 12.0107

Ca 40.078

Cr 51.9961

H 1.00794

Mg 24.3050

N 14.0067

Na 22.989770

O 15.9994

P 30.973761

Use the data from the periodic table shown above to answer the following questions.

These tutorials are part of a complete stoichiometry course developed with the Open Learning Initiative at Carnegie Mellon University. To access the entire course, please see http://www.cmu.edu/oli/courses/enter_chemistry.html.

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