The Empirical Formula and Simple Ratio of Atoms


The Empirical Formula and Simple Ratio of Atoms

Chemical formula of a compound lets us determine the amount of the elements available in a compound from its mass. What if you don’t know the chemical formula of a compound? At this time, you can derive the chemical formula of the compound from the available mass measurements.

The empirical formula is a formula that shows the ratio of the elements present in a compound. This is not the exact number of atoms in the molecule. The ratio is denoted by subscripts placed after the element symbol.

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Basically the empirical formula tells you about the most reduced elements and how many atoms of all the elements are present in the compound. Further, if the chemical formula of a compound can not be reduced further than the empirical formula is the same as the chemical formula of the compound. To know the empirical formula you can perform the calculations by yourself but if you want to save your time and to obtain the precise formula then visit website. It offers a free Empirical formula calculator and you can use it as much as you want. Students or professionals can easily use it to fulfill their needs.

What is an Empirical Formula?

Generally, the chemical formula is divided into three categories, empirical, molecular and structural. The empirical formula helps to find out the ratio of atoms available in a compound. The molecular formula represents the number of atom types in a molecule and the structural formula shows how the atoms are bonded together inside a molecule? 


Read further to have more knowledge about empirical formulas and simple ratio of atoms.


The molecular formula of the glucose is C6H12O6. If we reduce it then we will have the empirical formula. After reducing it we will have CH2O. Hence, this is the empirical formula of the glucose. This formula contains 2 moles of hydrogen, for each mole of the carbon and oxygen. 

How to Determine Empirical Formula?

Follow the below listed simple steps to determine the Empirical Formula:

  • Start with the number of grams of all the elements.

  • To make the calculations easy, imagine that the total mass of a sample is 100g so that you can work with simple percentages. Meanwhile, set the mass equal to the percent. The whole total should be equal to 100 %.

  • Utilize the molar mass that you obtain by summing up the atomic weight of the elements from the periodic table to turn the mass of all the elements into moles.

  • Now divide each mole value by the small number of the moles you get after performing the calculations.

  • After all of that round each number you get the nearest whole number. They are the mole ratio of elements that follow the element symbol.

However, sometimes it becomes tricky to get the whole number ratio and you have to use trial and error to get the correct value.  

Example: Find the Empirical Formula of a compound of Iron and Oxygen which contains 69.94 % iron and 30.06 % oxygen.

Given that:

Fe = 69.94 %

O  = 30.06 %

Formula to Calculate Number of Moles:

Number of Moles = Mass given in GramsMolar Mass of Element

The molar mass of each element changes according to the amount of the isotopes present in the compound. Most of the online empirical formula calculators also utilize this formula to find out the number of moles. 

69.94 g Fe x 1 mol Fe55.85 g Fe = 1.252 mol Fe

30.06 g O x 1 mol O16.00 g O = 1.879 mol O  

Now divide both moles with the smallest value.


Fe = 1.252 mol 1.252 = 1

O = 1.879 mol 1.252 = 1.5

Finally multiply each mole with the smallest whole number to make them whole.

2(Fe:O) = 2 (1:1.5) = 2:3.

Finally, the empirical formula of the compound is Fe2O3.

This example expresses the simple ratio of items in the compound. As you can see, the result of the calculation shows that there are two iron atoms and three oxygen atoms present in the compound. Performing this calculation every time will not be as simple as you see in the upper example. It could be a very long and time consuming task.  

Instead of doing all of that calculation you can simply use a free empirical formula calculator to get the empirical formula in a matter of seconds. 

Combustion Analysis:

A most common way to determine the elemental composition is an analytical procedure that is called combustion analysis. In this method a small amount of the compound as the sample is burned in the oxygen atmosphere. The other elements can be determined by other methods.

Whenever a compound is subject to combustion with oxygen in a special combustion apparatus. All the carbon is converted to CO2the hydrogen to H2O. In this way the amount of carbon can be easily determined by measuring the amount of the produced CO2. With the help of Magnesium perchlorate we can determine the amount of H produced by the H2O.

Alternatively, get the assistance of an online combustion analysis calculator to obtain the precise output in a couple of seconds.

How to find Empirical Formula Online?

Follow the below listed easy steps to calculate empirical formula by using an online empirical formula calculator:

Step 1:

Add the symbol and the percentage of mass into the toolbox of the calculator.

Step 2:

After adding the values, press the calculate button and wait for the completion of the process.

Step 3:

Once the process is completed, then hit the download icon to get the results in PDF format.

Final Words:

Empirical formula is the most basic form of notation. Usually, many ways are available to find out the empirical formula. But if you want to save the time and get the precise formula look no further than an online empirical formula calculator that lets you calculate countless imperial formulas without demanding any cost or additional chargers. 

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