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Moles Notes
Counting Units
• Dozen doughnuts• Cents in a dollar• Gallon of milk
Counting Atoms
Counting atoms requires a standard unit of measurement.The Mole
Amedeo Avogadro
• Actual name: Lorenzo Romano Amedeo Carlo Bernadette Avogadro di Quaregna e Cerreto
• Born August 9, 1776 in Turin, Italy
• Lawyer who dabbled in natural philosophy in his later life
Amedeo Avogadro
• Avogadro became important for some of his discoveries that he made
• Avogadro discovered that gases were not alone, but a molecule containing 2 atoms of the gas
• Like: O2, N2, I2
Avogadro’s Number
• Was NOT discovered by Avogadro, but attributed to him by the scientists who discovered the number.
• Avogadro’s number refers to the number of atoms in a specific amount of a substance. This amount is called a mole.
The Mole
• 1 mole is symbolized by (the unit) mol
• 1 mol = 6.02 x 1023 atoms
• 1 mole of any substance will contain 6.02 x 1023 atoms
Moles
• 1 mole of a substance will not always be the same size. However…..
• 1 mol of any gas at STP will fill 22.4L
1 mol of • Popcorn kernals would cover the continental 48
states to a depth of 310 miles• Sodapop cans would cover the Earth to a depth of
200 miles• If we were able to count atoms at the rate of 10
million per second, it would take about 2 billion years to count the atoms in one mole!
• If Uncle Chintzy had left you a mole of dollars, and you could count 24hrs a day it would take you 19,100,000,000,000,000 years (19 quadrillion)
• http://www.youtube.com/watch?v=TEl4jeETVmg
B. Molar Mass
B. Molar Mass Examples
Molar Masses
• What is the molar mass of sodium (Na)?• What is the molar mass of chlorine (Cl)?• What is the molar mass of calcium (Ca)?
• These numbers are found directly on the periodic table – rounded to one decimal place.