The Mole This is a quantity of atoms or molecules. A Dozen = 12 A Gross = 144 It allows us to...
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The Mole The Mole This is a quantity of atoms or molecules. A Dozen = 12 A Gross = 144 It allows us to “count” how many atoms we are using in a reaction!
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Transcript of The Mole This is a quantity of atoms or molecules. A Dozen = 12 A Gross = 144 It allows us to...
The MoleThe Mole
This is a quantity of atoms or molecules.A Dozen = 12A Gross = 144It allows us to “count” how many atoms we are using in a reaction!
The MoleThe Mole
In chemistry the mole = ….
602,000,000,000,000,000,000,000 atoms or molecules.
6.02x1023 atoms or molecules.
This number is called Avogadro’s Number.
The MoleThe Mole
How big is a mole? (useless facts ahead!)
A mole of watermelon seeds would be found in a watermelon that is slightly larger than the moon.
A mole of M&M’s would fill one-third of the Earth’s oceans.
The MoleThe Mole
A mole of donut holes could cover the Earth 5 miles deep.A mole of red blood cells would exceed the number found on every human on earth combined.A mole of pennies could pay the US national debt roughly 500 million times. (approx. $12 trillion as of today)
How Can We Count Atoms?How Can We Count Atoms?
Avogadro’s Principle
Equal volumes of gases (same Temperature & Pressure) have equal numbers of molecules.
[http://www.bulldog.u-net.com/avogadro/imgs/avogad.gif]
Early 1900’s – Scientists find approximate size of an atom.
The mole is then defined as the number of atoms in 12.0 g of carbon. (Avogadro’s Number!!!)
How Can We Count Atoms?How Can We Count Atoms?
The Mole II (Return of Bridges)The Mole II (Return of Bridges)
Mole (mol) – The number of atoms that are found in the molar mass of a given element.
Molar mass (M) is the atomic mass of an element measured in grams.[http://www.userwebs.pomona.edu/~cjt04747/Chem1/color_mole.jpg]
The Mole II (Return of Bridges)The Mole II (Return of Bridges)
6.02 x 1023
In 12.0 g of carbon
AtomsIn 18.0 g of H2O
Molecules (covalent!)In 58.5 g of NaCl
Formula Units (Ionic!)
Conversion factors for mole problems
The Mole II (Return of Bridges)The Mole II (Return of Bridges)
Example:
How many molecules of O2 are there in 1.50 moles of O2?
1.50 mol O2 6.02 x 1023 molec.1.0 mol O2
= 9.03 x 1023
molecules O2
Watch Significant Digits!!!
The Mole II (Return of Bridges)The Mole II (Return of Bridges)
Example:
How many grams of C2H4 are there in 3.0 moles of C2H4?
3.0 mol C2H4 28.0 g C2H4
1.0 mol C2H4
= 84 g C2H4
The Mole II (Return of Bridges)The Mole II (Return of Bridges)
Example:
How many grams of Ca are there in 7.2 x 1022 atoms of Ca?
7.2 x 1022 atoms
40.1 g Ca= 4.8 g
Ca6.02 x 1023 atoms
