Mole to Mass and Mass to Mole

•  some questions will give you an amount of moles and ask you to determine the the mass. 
•  converting moles to mass only requires one additional step

                                        MOLES ------------- MOLES
                                             I                                  I
                                             I                                  I
                                             I                                  I
                                        MASS                         MASS

EXAMPLES:

--How many grams of (Al2O3) are required to produce 3.5 mol of pure aluminium.

1. Balance the equation                                          Al2O3 -->    Al  +     O2
                                                                         2  Al2O3 --> 4 Al  +  3   O2
2.Find the molar mass of (Al2O3) = 102g
3. Solve the problem                                  3.5mol Al x 2 Al2O3 x 102g  = 178.5g --> 1.8x 10 power of 2
                                                                                       4 Al        1 mol

-- How many grams of water are produced of 0.84 mol of (H3PO4) is completely neutralized barium hydroxide?

2H3PO4 + 3Ba(OH)2  --> 6H(OH) + Ba3 (PO4)2

0.84 mol x 6 x 1.8g  = 45.36g --> 45g
                 2   1mol
Nicole H