COUNTING ATOMS
When Objects Contain too many atoms to count or weigh individually, we give them the title of Macroscopic. Because of this, Amedeo Avogadro proposed that the number of Atoms in 12,000,000 grams of Carbon should be equal to one mole of Carbon. This number is now the basis of all quantitative chemistry.
When Objects Contain too many atoms to count or weigh individually, we give them the title of Macroscopic. Because of this, Amedeo Avogadro proposed that the number of Atoms in 12,000,000 grams of Carbon should be equal to one mole of Carbon. This number is now the basis of all quantitative chemistry.
Almost exclusively a chemistry term, a mole is a multitude of things, like a pair (two of something), a dozen (twelve of something) or a century (one hundred of something). To get a better sense of the size of a mole, one mole of meters would cross the entire galaxy over 3000 times; and one mole of seconds is almost 100,000 times more than the age of the universe.
Another great example Mr.Doktor gave us was "The Pea Analogy."
| 100 | 1 | One pea |
| 101 | 10 | 10 peas - spoonful |
| 102 | 100 | 10 spoonfuls of peas - plateful |
| 103 | 1000 | 10 platefuls of peas - bag |
| 104 | 10 000 | 10 bags of peas |
| 105 | 100 000 | 100 bags of peas - fridgeful |
| 106 | 1 000 000 | 10 fridgefuls of peas - an average bedroom |
| 107 | 10 000 000 | Average house full from basement to attic with peas |
| 109 | 1 000 000 000 | 100 houses full from basement to attic with peas - a small village |
| 1012 | 1 000 000 000 000 | 100 000 houses full from basement to attic with peas - a small city |
| 1015 | 1 000 000 000 000 000 | A large city like New York covered 1 m deep with peas |
| 1018 | 1 000 000 000 000 000 000 | A province like Alberta covered 1 m deep with peas |
| 1020 | 100 000 000 000 000 000 000 | The land mass of Canada covered 1 m deep with peas |
| 1021 | 1 000 000 000 000 000 000 000 | The land mass of the world covered 1 m deep with peas |
| 1023 | 100 000 000 000 000 000 000 000 | The entire surface of the earth plus 99 planets just like earth covered 1 m deep with peas |
| 6.02 x 1023 | 602 000 000 000 000 000 000 000 | 602 planets like earth covered 1 m deep with peas = 12 pencil leads = one mole of carbon atoms = 1/18 the surface area of the Sun |
As you now know, a mole represents a HUGE number of particles (ie. atoms, molecules, or formula units). Throughout this unit, we will abreviate molecules as "molec" and formula units as "FU." A formula unit is the empirical formula of an ionic or covalent network solid compound used as an independent entity for stoichiometric calculations.
EXAMPLES
-A Sample of Carbon contains 2.47 x 1025 atoms. How many moles of Carbon is this?
(2.47 x 1023) atoms x 1/(6.02x1023)
= 41.0mol
-12.5 moles of O2 represents how many molecule?
12.5mol x (6.02x1023) FU/1mol
=7.53x 10^24 molec
-How many formula units are present in 0.57 mol of BaCl2?
0.57mol x (6.02 x 1023) FU/1mol
=3.43 x 1023FU
Extra practice::
Next time: Molar Mass
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