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Chemistry: Compound Composition

Please discuss how to find the molar mass of a compound, percent composition of the elements of a compound and how to determine the empirical and molecular formulas from percent composition.

Solution Preview

How to find the molar mass. The molar mass is the sum of all the atomic masses of the elements in a compound.
1. Find the atomic mass of each element in the compound by using the periodic table.
2. If there are any subscripts, multiply the atomic mass by the subscript.

Example 1:
Mn= 55 g/mol O= 16 g/mol
(1x55) +(2x16)
55+ 32=87g/mol

Example 2:
Mg=24 g/mol P=31g/mol O=16g/mol
(3x24) +(2x31)+(8x16)=262 g/mol
This is an important concept to understand because you will need it for other calculations in chemistry. One such case is figuring out the % composition of a compound.

Percent Composition:
1. Look up the atomic masses in the periodic ...

Solution Summary

This solution will discuss how to calculate the following: molar mass, percent composition, empirical formula and molecular formula from percent composition. Examples are provided for each concept.