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Meaning, use and calculation of empirical formulas

In this introduction are given the explanation of how to find out an empirical formula if one has found out the chemical elements of an unknown substance and measured their ratio of masses. Also, it is described how one can calculate the ratio of masses from a given empirical formula.
Two examples and the explanation of the principles of "how to calculate" are given here.

Solution Preview

The empirical formula tells us which sort of chemical elements and how many atoms of every one are necessary to form a chemical substance.
But what can we do with this information?

Here are two examples:

1.) The first point is that we have a chemical compound which consists of more than one chemical element. Let us say rocksalt, NaCl, for example. As we can see there are two elements namely sodium (Na) and chlorine (Cl). Their ratio of number of atoms here is 1:1, i.e. 1 Na and 1 Cl atom.
Since we know that every chemical element's atoms have different masses we can see easily that the MASS ratio of Na and Cl is even NOT 1:1.

So, how can we calculate the mass ratio of these elements in NaCl?

First of all we need the atomic masses of both Na ...

Solution Summary

In this introduction are given the explanation of how to find out an empirical formula if one has found out the chemical elements of an unknown substance and measured their ratio of masses. Also, it is described how one can calculate the ratio of masses from a given empirical formula under use of the atomic weights of the elements.
Two examples and a step-by-step explanation of the ways of "how to do" are given here. With these examples a student can understand how to solve this important question for both inorganic and organic compounds.

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