Graphite with AFM showing all atoms within the hexagonal graphite unit cells. Image size 2 - PowerPoint PPT Presentation

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Graphite with AFM showing all atoms within the hexagonal graphite unit cells. Image size 2

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Graphite with AFM showing all atoms within the hexagonal graphite unit cells. Image size 2 2 nm2. 77 pm resolution. Subatomic structures are visible within single ... – PowerPoint PPT presentation

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Title: Graphite with AFM showing all atoms within the hexagonal graphite unit cells. Image size 2


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Graphite with AFM showing all atoms within the
hexagonal graphite unit cells. Image size 22
nm2.
STM image (7 nm x 7 nm) of a single zigzag chain
of cesium atoms (red) on a gallium-arsenside
surface (blue) Photo courtesy National Institute
of Standards and Technology (NIST
77 pm resolution. Subatomic structures are
visible within single tungsten atoms. Image size
500 500 pm2
3
Using Mass to Count Things
  • Atoms are so tiny it is impossible to count
    number of atoms in even 1 gram of matter
  • We use mass to count atoms

4
Counting by mass
  • a pile of nails weighs 1227 g
  • one nail has mass of 0.450 grams
  • How many nails are in pile?

1227g_____ 2726.6 nails 0.450 g
per nail
5
What is a mole?
No, not this kind of mole!
6
The MOLE
  • Unit used to count numbers of atoms
  • Count-by-mass technique
  • Defined as of atoms in 12.0 grams of C-12
  • This is the STANDARD!
  • 12.0 g of C-12 has 6.0221415 X 1023 atoms

7
Just how big is a mole?
Mole movie
8
The MOLE
  • 1 mole of any element has 6.02 X 1023 particles
  • This is a really big number Its so big because
    atoms are really small!

9
6.02 X 1023 Avogadros Number
  • One mole of water 6.02 X 1023 water molecules
  • One mole of gorillas 6.02 X 1023 gorillas
  • One mole of He atoms 6.02 X 1023 He atoms
  • One mole of anything 6.02 X 1023 of that thing

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Similar Words
  • Pair 1 pair shoelaces 2 shoelaces
  • Dozen 1 dozen oranges 12 oranges
  • Gross 1 gross spider rings 144 rings
  • Ream 1 ream paper 500 sheets of paper
  • Mole 1 mole Na atoms
  • 6.02 X 1023 Na atoms

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Equalities
  • 1 mole of C-12
  • 12.0 grams of C-12
  • 6.02 X 1023 atoms of C-12
  • 0.5 mole of C-12
  • 6.0 grams of C-12
  • 3.01 X 1023 atoms of C-12

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Equalities
  • 1 mole of C-12
  • 12.0 grams of C-12
  • 6.02 X 1023 atoms of C-12
  • 0.25 mole of C-12
  • 3.0 grams of C-12
  • 1.50 X 1023 atoms of C-12

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Equalities
  • 1 mole of C-12
  • 12.0 grams of C-12
  • 6.02 X 1023 atoms of C-12
  • 2 moles of C-12
  • 24.0 grams of C-12
  • 12.04 X 1023 atoms of C-12 1.204 X 1024 atoms
    of C-12

15
Molar mass for any element
  • molar mass of any element
  • take atomic mass and replace amu with grams
  • 1 mole Ne 20.179 g 6.02 X 1023 atoms
  • 1 mole Ar 39.948 g 6.02 X 1023 atoms
  • 1 mole Kr 83.80 g 6.02 X 1023 atoms
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