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and the MOLE. Using Mass to Count Things. Atoms are so tiny it is impossible to count # atoms in only 1 gram of matter use mass to “count” atoms. Counting by mass. You have a pile of nails that weighs 1227 g One nail has a mass of 0.450 grams How many nails are in the pile?. - PowerPoint PPT Presentation
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andand
the MOLEthe MOLE
Using Mass to Count Things
• Atoms are so tiny it is impossible to count # atoms in only 1 gram of matter
use massmass to “count” atoms
Counting by mass
• You have a pile of nails that weighs 1227 g
• One nail has a mass of 0.450 grams
• How many nails are in the pile?
1227g = 2726.6 nails 0.450 g per nail [Let’s call it 2730 nails]
What is a mole?
Not this kind of mole!
The MOLE
• Unit used to “count” # atoms
• Count-by-mass technique
• Defined: # atoms in 12.0 grams of C-12– This is the STANDARD!
• 12.0 g of C-12 has 6.0221415 X 1023 atoms
The MOLE
• 1 mole of any element has 6.02 X 1023 particles
• This is a really big number – It’s so big because atoms are really small!
6.02 X 1023 = Avogadro’s Number
• One mole of water = 6.02 X 1023 water molecules
• One mole of gorillas is 6.02 X 1023 gorillas
• One mole of He atoms is 6.02 X 1023 He atoms
• One mole of anything is 6.02 X 1023 of that thing
Similar Words
• PairPair: 1 pair of shoelaces = 2 shoelaces
• DozenDozen: 1 dozen oranges = 12 oranges
• GrossGross: 1 gross of spider rings = 144 rings
• ReamReam: 1 ream of paper = 500 sheets paper
• MoleMole: 1 mole of Na atoms =
6.02 X 1023 Na atoms
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
Equalities1 mole C-12
=
12.0 g C-12
=
6.02 x 1023
atoms C-12
0.25 mole of C-12
=
3.0 grams of C-12
=
1.50 X 1023 atoms of C-12
Equalities1 mole C-12
=
12.0 g C-12
=
6.02 X 1023
atoms C-12
2 moles of C-12
=
24.0 grams of C-12
=
12.04 X 1023 atoms C-12
[= 1.204 X 1024 atoms C-12]
Can this help with other elements?Can this help with other elements?
What is the mass of 1 mole of Mg (magnesium)?
1 mole of Mg = 24 grams
MOLAR mass for any element:
molar mass of any element = atomic mass in g/mole
1 mole Ne = 20 g/mol [= 6.02 X 1023 atoms]
1 mole Ar = 40 g/mol [= 6.02 X 1023 atoms]
1 mole Kr = 84 g/mol [= 6.02 X 1023 atoms]
Simple Mole Map
No. of Particles
No. of Moles
No. of Grams
No. ofLiters
x by
x by
x by
by
by by6.02 x 1023 particles/m
ol 22.4 L/mol
formula mass
