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Mole
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Arent moles animals that burry in holes? No! Its a unit used by chemists.

What is the mole?

 

The Mole is a unit used by Chemists to count atoms or molecules of a certain substance that they are dealing with. The unit of moles is used because it is impossible, at this point in time, to actually see a single atom. If a chemist wants atoms to be big enough to count visually, it would be really impractical since almost everything we can see is made up of billions of atoms and molecules. But even though we cannot see single atoms we can still count roughly how many are present. To do that you have to use Moles.

 

Mole triangle:

moletriangle.jpg

The mole triangle is a simple way of visualizing how to convert the numbers given to you.

 

e.g.: Lets say your given 2.00g of H2O and want to find out the number of moles (mol) present.

       To get from g mol you have to use the equation: g / molar mass = moles

The reason you have to divide the g by the molar mass and NOT multiply is because you are moving up the triangle.

Note: Whenever you move UP the triangle on either side you divide, when you move DOWN the triangle you multiply.

 

In this equation your given g so you can fill in part of your equation right away:

                        2.00g of H2O / molar mass = moles

 

Next you have to find your molar mass. On your periodic table the atomic mass of each element is written down, well molar mass is the total mass of the elements youre given. In this case you have H2 and O. An easy way to do the molar mass is to show your work like this:

 

H2: 1g X 2 = 2g

O: 16g

 

2g + 16g= 18g/ mol

 

Next you have to put your molar mass into your equation:

 

2.00g of H2O / 18g/ mol = mol

 

Now you can divide your g by your molar mass to find your moles:

 

2.00g of H2O / 18g/ mol = .11mol of H2O

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