1. A warm up… 1 trio = 3 singers 1 six-pack Cola = 6 cans soda 1 dozen donuts = 12 donuts 1 gross...
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Transcript of 1. A warm up… 1 trio = 3 singers 1 six-pack Cola = 6 cans soda 1 dozen donuts = 12 donuts 1 gross...
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The Moleand
Molar Mass
What’s missing?
The measurements!
A warm up…1 trio = 3 singers
1 six-pack Cola = 6 cans soda
1 dozen donuts = 12 donuts
1 gross of pencils = 144 pencils
Moles of Particles
Contains 6.02 x 1023 particles
1 mole (mol) C = 6.02 x 1023 C atoms
1 mol H2O = 6.02 x 1023 H2O
molecules
1 mol NaCl = 6.02 x 1023 Na+ ions and
6.02 x 1023 Cl– ions
Examples of MolesMoles of elements
1 mol Mg = 6.02 x 1023 Mg atoms
1 mol Au = 6.02 x 1023 Au atoms
Moles of compounds
1 mol NH3 = 6.02 x 1023 NH3 molecules
1 mol C9H8O4 = 6.02 x 1023 aspirin
molecules
Avogadro’s Number
6.02 x 1023 particles 1 mole
or
1 mole
6.02 x 1023 particles
Molar Mass
Number of grams in 1 mole =
the atomic mass
1 mole of C atoms = 12.0 g
1 mole of Mg atoms = 24.3 g
1 mole of Cu atoms = 63.5 g
What are the number of atoms in 0.500 mol of Al?3.01 x 1023 Al atoms
0.500 mol Al 6.02 x 1023 Al atoms 1 mol Al
What are the number of moles of S if a sample of S contains 4.50 x 1024 S atoms?
7.5 mol S atoms
4.50 x 1024 S atoms 1 mol S 6.02 x 1023 S atoms
Learning Check
Learning CheckCalculate the molar mass
A. 1 mole of Br atoms =________
B. 1 mole of Sn atoms = ________
79.9 g/mole
118.7 g/mole
Molar Mass of Compounds
Mass of compounds in g/mol = the sum of all of its atomic masses
CaCl2
(1 mole Ca x 40.1 g/mol) + (2 moles Cl x 35.5 g/mol)
1 mole of CaCl2 = 111.1 g/mol
N2O4 (2 moles N x 14.0 g/mole) + (4 moles O x 16.0 g/mole)
1 mole of N2O4 = 92.0 g/mole
Molar Mass of Compounds
Calculations with Molar Mass
Grams Moles Atoms/Molecules
Use 6.02 x 1023 (particles/mole)Use molar mass
(grams/mole)
14
Moles and GramsAluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al?
1. Molar mass of Al = 27.0 g Al
2. Conversion factors for Al 27.0g Al or 1 mol Al
1 mol Al 27.0 g Al
3. Setup 3.00 mol Al 27.0 g Al 1 mol Al
Answer = 81.0 g Al
Learning Check
The artificial sweetener aspartame (Nutri-Sweet) formula
C14H18N2O5 is used to sweeten diet
foods, coffee and soft drinks. How many moles of aspartame are
present in 225 g of aspartame?
Solution1. Molar mass of Aspartame C14H18N2O5
(14 x 12.0) + (18 x 1.01) + (2 x 14.0) + (5 x 16.0)
= 294 g/mole
2. Setup 225 g aspartame 1 mole aspartame
294 g aspartame
Answer = 0.765 moles of
aspartame
Learning Check How many atoms of Aluminum
are in 17 grams of Aluminum?
17 grams Al 1 mole Al 6.02 x 1023 atoms 27.0 grams Al 1 mole Al
Answer = 3.8 x 1023 atoms of Al