Molar Mass

Oct 21, 2009 at 7:06 PM
Atomic Mass:
-The mass of 1 mole of atoms in an element
-The mass of 1.0 mol of 'C' atoms is 12.0g
-The mass of 1.0mol of 'Ca' atoms is 40.1g

Molecular Mass:
-The mass of 1.0 mole of atoms of an element or compound
N2, O2, H2, Br2, Cl2, F2, I2, P4, S8
-Assume all the rest are monoatomic
Element Symbol Formula Atomic mass Molar mass
Iodine I I2 126.9 g/mol 253.8g/mol
Silicon Si Si 28.1g/mol 28.1g/mol
Hydrogen H H2 1.0g/mol 2.0g/mol
Iron Fe Fe 55.8g/mol 55.8g/mol
Neon Ne Ne 20.2g/mol 20.2g/mol

Finding the molar mass of compounds:
-H2o
----> 2 H = 2(1.0) =2.0
----> 1 O = 1(16.0) =16.o
---->=18.0g/mol
-Find the molar mass of ammonium phosphate (NH4)3PO4
---->3N=2(14.0)
---->12H=12(1.0)
---->1P=1(31.0)
---->4O=4(16.0)
---->=149g/mol

Converting mass <----> moles:
-conversion factor g/mol or mol/g
-Find the mass of 2.5 mol of water
H20----> 18.og/mol 1mol/18.0g X 2.5mol =1/45g=45g
-Find the number of moles in 391g sample of nitrogen dioxide
NO2----> 1N=1(14.0), 2O= 2(16.0), =46g/mol
391 X 1mol/46g=8.5mol



In case you still don't understand, here's a short video:


And this is video is just for laughs:

1 Responses to Molar Mass

  1. Mr. Doktor Says:

    Interesting combination of videos. One is quite useful the other one is, well, odd. Still, they make the blog rather amusing. Aside from that try and make up your own examples instead of just writing down the ones we do in class. But all in all good job so far!