Mole Conversions

Now that we have learned how to calculate atomic mass, formula mass, and molecular mass it is time to learn about mole conversions!

*REMEMBER* Avagadro’s Number: 6.022 x 10^23 particles/mole

Here is a chart to help you out along the way!

                Molar Mass                Avagadro’s Number

                 ÷                      ÷

    GRAMS    àà      Moles    à à   Atoms/Molecules

                        ßß                           ß ß  

                          X                                  X

Conversions from particles ↔ moles

            Particles → Moles

            (Particles also represent atoms, molecules, formula units etc…)

            Example:

            1) Lets say you want to convert 3.0 x 10^16 atoms of Silver into moles.

           

            3.0 x 10^16 atoms of Ag   x     1 mole

                                                            ‒‒‒‒‒‒‒

                                                    6.022 x 10^23 atoms

                    = 5.0 x 10^-8 moles of Ag

            2) 3.01 x 10^24 particles of carbon → moles

             3.01 x 10^24 particles    x     1 mole

                                                       ‒‒‒‒‒‒‒‒‒‒

                                                6.022 x 10^23 particles

                = 5.00 moles of carbon

*Remember to use significant figures for all calculations.

Moles → Particles/molecules/formula units/atoms

1)      0.75 moles of CO2 → molecules

0.75 moles x  6.022 x 10^23 molecules 

                      ‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒‒
                                   1 mole

= 4.5 x 10^23 molecules of CO2

2) 0.75 moles of CO2 → atoms of oxygen
     4.5 x 10^23 molecules CO2    x    2 atoms of O
                                                          ‒‒‒‒‒‒‒‒‒‒‒‒
                                                         1 molecule CO2

            = 9.0 x 10^23 atoms of oxygen

Conversions between moles ↔ grams

Moles→ Grams

1)      2.04 moles of carbon → grams
*use molar mass of Carbon = 12.0 g/mol

   2.04 moles x 12.0 grams
                     ‒‒‒‒‒‒‒‒‒‒
                         1 mole

= 24.5 grams of carbon

2)      0.341 moles NO2 → grams

molar mass of NO2 = 46.0 g/mol

0.341 moles x  46.0 g

                       ‒‒‒‒‒‒

                        1 mole

= 15.7 grams of NO2

Youtube time! Here is another example!

http://www.youtube.com/watch?v=NMdN1LtHuDA

Grams → Moles

1)      3.45g of carbon → moles

3.45  x   1 mole

             ‒‒‒‒‒‒‒
                12.0g

= 0.288 moles of carbon

2) 6.2g of MgCl2 → moles

            6.2g   x  1 mole
                        ‒‒‒‒‒‒‒

                        95.3g

= 0.065 moles of MgCl2

Youtube time! Here is another example!

http://www.youtube.com/watch?v=ehepBBtSbDc

By Candace