Wednesday, November 24, 2010

Mole Conversions Part 2

Last class, we learned how to convert between particles to mass (grams); and conversions between mass (grams) to particles.

1) Particles→ Grams
  • To find the mass of the molecule, another step is added to the equation from last time.   
  • Ex: You want: 7.49x 10^21 atoms of Colbalt into grams,            
                          = 7.49x 10^21 atoms x 1 mole       x       58.9g = 0.733 of Cobalt.
                                                               ‒‒‒‒‒‒              ‒‒‒‒‒
                                                  6.022 x 10^23                1 mole
                           * the grams is the atomic mass of Cobalt

2) Grams → Particles    
  • From the example above, the placement of 6.022 x 10^23 and the grams are swapped when converting grams→particles.
  • Ex: You want the number of particles in 6.24 grams of Phosphorous.
                      = 6.24g x 1 mole x 6.022 x 10^23 = 1.21 x 10^23 atoms of Phosphorous
                                      ‒‒‒‒‒     ‒‒‒‒‒‒‒‒‒‒‒
                                      31.0g           1 mole

     * Please remember that significant figures always applys to the answers!

Here is a Mole Map to understand this concept visually!

For more expamples and practice visit this website!


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