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.