Chemistry 11 October 20/09

Today in Chemistry 11 we learned about Atomic Mass.
-the mass of 1 mole of atoms of an element
Ex.
mass of 1 mole of "C" atoms is 12.0g
mass of 1 mole of "Ca" atoms is 40.1g

Molar Mass
- the mass in grams of 1 mole of molecules of an element or compound is the molar mass for the diatomics you would times there mass by two if there by themselves H2, Cl2, F2, I2, O2, N2, Br2, and same goes for the molecular ones P4, S8

Element Symbol Formula Atmoic Mass Molar Mass
Bromine Br Br2 79.9 159.8
Neon Ne Ne 20.2 20.2
Silicon Si Si 28.1 28.1
Hydrogen H H2 1 2
Iron Fe Fe 55.8 55.8

For compounds add the molar masses of all the atoms
Ex.
H2O
2H - 2
1O - 16
H2O = 18g/mol

Ca(NO3)2
1Ca - 40.1
2N - 28
6O - 96
Ca(NO3)2 = 164.1g/mol

When you are converting Grams to Moles you would want it to be g/mol or mol/g
Ex.
Find the mass of 2.5moles of water
2.5 mol of H2o * 18.0g/1mol= 45g


Find the number of moles in 391g sample of nitrogen dioxide

381g NO2 / 46g*1mol = 8.5 mols

62.6mg of C12H22O11 = ? moles
C12 = 144
H22 = 22
O11 = 176
C12H22O11 = 342

.0626g of C12H22O11 / 342g * 1mol = 1.83 * 10 to the negative 4

Down here is a video showing how to convert moles to grams