Avogadro

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Avogadros Number
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Amadeo Avogadro

• Amadeo Avogadro (1766-1856) never knew his own
  number it was named in his honor by a French
  scientist in 1909. its value was first estimated
  by Josef Loschmidt, an Austrian chemistry
  teacher, in 1895.

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Things to understand about Avogadro's number

• It is a number, just as is "dozen", and thus is
  dimensionless you can think of Avogadro's number
  as the "chemist's dozen".
• It is a huge number, far greater in magnitude
  than we can visualize

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• Avogadros number ? number of representative
  particles in one mole which is equal to 6.02 x
  1023
• (602,000,000,000,000,000,000,000)
• SEXTILLION 
• Its practical use is limited to counting tiny
  particles like atoms, molecules, "formula units",
  electrons, or photons.
• Formula mass molar mass 1 mole 6.02 x 1023

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How big is that?

• If you had Avogadro's number of unpopped
• popcorn kernels, and spread them across the
• United States of America, the country would be
• covered in popcorn to a depth of over 9 miles.
• Or..you could cover the ENTIRE EARTH 200
• miles deep in soda cans!

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Converting between moles and particles

• 1. To calculate of moles ()
• Particles 1 mol
  MOLES
• (given)
• 6.02 x 1023
  particles

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• To calculate of particles  (X)
• Moles 6.02 x 1023 particles
• (given)
  PARTICLES
• 1 mol
• REMEMBER You do not calculate formula mass
  for mole and particle conversions.

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SAMPLE A (Particles ? Moles) ()

• 1. How many moles are in 7.14 x 1023 molecules?

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SAMPLE B (Moles ? Particles) (x)

• 2. How many molecules are there in 4.0 moles of
• H2O2?

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Moles ? Particles

• 2 moles ? particles

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• 0.75 moles ? particles

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• 0.35 moles ? particles

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Particles ? Moles

• 1.204 x 1024 particles ? moles

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• 3.4 x 1026 particles ? moles