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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.

© BrainMass Inc. brainmass.com July 18, 2018, 8:30 pm ad1c9bdddf

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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:
MnO2
Mn= 55 g/mol O= 16 g/mol
(1x55) +(2x16)
55+ 32=87g/mol

Example 2:
Mg3(PO4)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.

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