170 likes | 321 Views
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?.
E N D
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? 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 • Pair: 1 pair of shoelaces = 2 shoelaces • Dozen: 1 dozen oranges = 12 oranges • Gross: 1 gross of spider rings = 144 rings • Ream: 1 ream of paper = 500 sheets paper • Mole: 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
0.25 mole of C-12 = 3.0 grams of C-12 = 1.50 X 1023 atoms of C-12 Equalities 1 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? Equalities 1 mole C-12 = 12.0 g C-12 = 6.02 X 1023 atoms C-12
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]
No. of Grams by No. of Moles by by No. of Liters No. of Particles formula mass x by x by 6.02 x 1023 particles/mol x by 22.4 L/mol