Title: Graphite with AFM showing all atoms within the hexagonal graphite unit cells. Image size 2
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2Graphite 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
3Using 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
4Counting 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
5What is a mole?
No, not this kind of mole!
6The 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
7Just how big is a mole?
Mole movie
8The 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!
96.02 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
10Similar 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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12Equalities
- 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
13Equalities
- 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
14Equalities
- 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
15Molar 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