*Gram - Mole Conversions*
*By: Erin F. and Nathalie T.*
amedeoavogadro.jpg
Amadeo Avogadro. From http://www.teachersparadise.com/ency/nl/media/8/85/amedeoavogadro.jpg



Amedeo Avogadro (1776-1856) was the author of "Avogadro's Hypothesis" in 1811. Combined with Gay- Lussac's Law of Combining Volumes, it removed all doubt about the establishment of the atomic weight scale. "Avogadro's Number" is an honorary name attached to the calculated value of the number of atoms and molecules in a gram mole of any chemical substance.



Avogadro's number is 6.022 x 10^23. Mole day is celebrated on October 23 (10/23)!!














Mole

The mole is the amount of substance of a system which contains as many elementary entities as there are atoms in 0.012 kilogram of carbon 12

To perform a gram/mole conversion:
Our goal is to determine the number of moles of Mg in 4.67 grams.
First, find the atomic mass for magnesium on the periodic table. The atomic mass is equal to 24.305 grams.
One mole of Mg weighs 24.305 grams, which gives a conversion factor from grams to moles.
Using the factor 1 mol/24.305g:
moles Mg = 4.67g x 1mol/24.305g = 0.192 mol

The end result is in moles because the two grams in the equation cancel each other out. We used the conversion factor 1 mol/24.305g because we were converting from grams to moles (If we were to be doing the opposite, converting moles to grams, we would have used the conversion factor 24.305g/1 mol).


*note: a demonstration of how to do this problem is shown below!

Practice Problems:
Q: Determine the number of grams in 2.73 moles of nitrogen.
A: 38.2 grams

Q: Determine the number of moles in 167.1 grams of silver.
A: 107.868 moles

Q: Determine to number of grams in 0.0441 moles of lead.
A: 207.2 grams


(
http://chemistry.about.com/od/workedchemistryproblems/a/molegramconvert.htm)



periodic.gif
Periodic Table http://images.google.com/imgres?imgurl=http://library.thinkquest.org/3616/chem/periodic.gif&imgrefurl=http://library.thinkquest.org/