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 ParticlesContains 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 compounds1 mol NH3 = 6.02 x 1023 NH3 molecules1 mol C9H8O4 = 6.02 x 1023 aspirin
molecules
Molar MassNumber of grams in 1 mole =
the atomic mass
1 mole of C atoms = 12.0 g1 mole of Mg atoms = 24.3 g1 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
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)
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 Al2. Conversion factors for Al
27.0g Al or 1 mol Al 1 mol Al 27.0 g Al3. Setup 3.00 mol Al 27.0 g Al
1 mol AlAnswer = 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