How to Calculate Molar Mass

How to Calculate Molar Mass

Moles are a unit of measurement of chemicals. A mole is the atomic weight of a molecule of the chemical in grams and it is used very commonly in chemistry, so I’m going to show you how to calculate molar mass.

You can find the molar mass right on the periodic table. On the table, there is the element symbol, the atomic number, and the molar mass.

PeriodicTable-56a128ab5f9b58b7d0bc938c

Here I’ve got some elements:

 

Nitrogen’s molar mass is 14.0067 g/mol, for oxygen, it’s 15.9994 g/mol, and for silver, it’s 107.8682 g/mol.

The first method of finding the molar mass is to look right on the table (just like I did).

The second method is to add up the masses of each atom (.Add up the masses of the atoms that form the compound) I’ll show how with the chemical silver nitrate.


AgNO3

One Silver molecule: 107.8682 + one Nitrogen molecule 14.0067 + and three molecules of Oxygen: (15.9994 x 3)

107.8682 + 14.0067 + (15.9994 x 3) = 169.8731

AgNO3 = 169.87 g/mol


Let’s try another one:

NaOH

One Sodium molecule: 22.989769 + One Oxygen: 15.9994 + and one Hydrogen: 1.00794

22.989769 + 15.9994 + 1.00794 = 39.997 g/mol

NaOH = 39.997 g/mol


H2SO4

Two Hydrogens: (2 x 1.00794) + One Sulfur: 32.07 + Four Oxygens: (4 x 16.00)

(2 x 1.00794) + 32.07 + (4 x 15.9994) = 98.079 g/mol

H2SO4 = 98.079 g/mol


 

I hope you understand, leave a comment if you have any questions or if there are any mistakes ↓

 

Sources:

http://www.qrg.northwestern.edu/projects/vss/docs/propulsion/3-what-is-a-mol.html

https://www.youtube.com/watch?v=F9NkYSKJifs

9 Replies to “How to Calculate Molar Mass”

  1. Thank you. If I round off the numbers to much, it’ll not be quite as accurate. For example: HCI is 36.46 g/mol, if I round off the numbers it might be 37 or 38. Anyways, thank you for coming to my post 🙂

  2. Nicely done. 🙂
    I like how you are very specific as to the exact weight. When I was at school, we just used 16 for Oxygen etc It made it a lot easier 🙂

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