What is a Mole? (watch the video)

Collection Terms 1 trio = 3 singers 1 six-pack Cola = 6 cans Cola drink 1 dozen donuts = 12 donuts 1 gross of pencils = 144 pencils

A Moles of Particles Contains 6.02 x 1023 particles 1 mole C = 6.02 x 1023 C atoms 1 mole H2O = 6.02 x 1023 H2O molecules 1 mole NaCl = 6.02 x 1023 Na+ ions and 6.02 x 1023 Cl– ions

Examples of Moles Moles of elements 1 mole Mg = 6.02 x 1023 Mg atoms 1 mole Au = 6.02 x 1023 Au atoms Moles of compounds 1 mole NH3 = 6.02 x 1023 NH3 molecules 1 mole C9H8O4 = 6.02 x 1023 aspirin molecules

6.02 x 1023 particles 1 mole or 1 mole Avogadro’s Number 6.02 x 1023 particles 1 mole or 1 mole

Amedeo Avogadro

Molar Mass Number of grams in 1 mole Equal to the numerical value of 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

Learning Check Give the molar mass to 0.1 g A. 1 mole of Br atoms = ________ B. 1 mole of Sn atoms = ________

Solution Give the molar mass to 0.1 g A. 1 mole of Br atoms = 79.9 g/mole B. 1 mole of Sn atoms = 118.7 g/mole

Molar Mass of Compounds

Molar Mass of Compounds Mass in grams of 1 mole equal numerically to the sum of the atomic masses 1 mole of CaCl2 = 111.1 g/mole 1 mole Ca x 40.1 g/mole + 2 moles Cl x 35.5 g/mole 1 mole of N2O4 = 74.0 g/mole 2 moles N x 14.0 g/mole + 4 moles O x 16.0 g/mole

Learning Check A. 1 mole of K2O = ______g B. 1 mole of antacid Al(OH)3 = ______g

Solution A. 1 mole of K2O = 94.2 g 2 K x 39.1 g/mole + 1 O x 16.0 g/mole B. 1 mole of antacid Al(OH)3 = 78.0 g 1 Al x 27.0 g/mole + 3 O x 16.0 g/mole + 3 x 1.0

Learning Check Prozac, C17H18F3NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of 1) 40.0 g/mole 2) 262 g/mole 3) 309 g/mole

Solution Prozac, C17H18F3NO, is a widely used antidepressant that inhibits the uptake of serotonin by the brain. It has a molar mass of 3) 309 g/mole 17C (12.0) + 18H (1.0) + 3F (19.0) + 1N (14.0) + 1 O (16.0)

Gasses are weird…

Mass, Volume, Mole Relationship

Welcome to Mole Island 1 mol = molar mass 1 mole = 22.4 L @ STP 6.02 x 1023 particles

Stoichiometry Island Diagram Known Unknown Substance A Substance B M Mass Mass Mountain Mass Mole Island Volume Mole Mole Volume V Liter Lagoon Particles Particles P Particle Place Stoichiometry Island Diagram

Stoichiometry Island Diagram Known Unknown Substance A Substance B M Mass Mass Mountain Mass Volume Mole Mole Volume V Liter Lagoon Particles Particles P Particle Place Stoichiometry Island Diagram

Stoichiometry Mole Island Diagram When in doubt…convert to moles! Known Unknown Substance A Substance B Mass Mass 1 mole = molar mass (g) 1 mole = molar mass (g) Use coefficients from balanced chemical equation Volume Mole Mole Volume 1 mole = 22.4 L @ STP 1 mole = 22.4 L @ STP (gases) (gases) 1 mole = 6.022 x 1023 particles (atoms or molecules) 1 mole = 6.022 x 1023 particles (atoms or molecules) Particles Particles

A. Using Mole Island Zn + 2HCl  ZnCl2 + H2 79.1 g ? L 79.1 g Zn 1 mol Just watch, don’t write: If you have 79.1 g of Zn to react with excess HCl (enough HCl to keep reacting as long as you need), how many Liters of H2 gas will be produced? Zn + 2HCl  ZnCl2 + H2 79.1 g ? L 79.1 g Zn 1 mol Zn 65.39 g Zn 1 mol H2 Zn 22.4 L H2 1 mol = 27.1 L H2

B. Using Mole Island Zn + 2HCl  ZnCl2 + H2 ? L 79.1 g 79.1g HCl 1 mol Now write this one for practice: If you instead have 79.1 g of HCl to react with excess Zinc (enough Zinc to keep reacting as long as you need), how many Liters of H2 gas will be produced? Zn + 2HCl  ZnCl2 + H2 ? L 79.1 g 79.1g HCl 1 mol HCl 36.5g HCl 1 mol H2 2 mol HCl 22.4 L H2 1 mol = 24.3 L H2

Zn + 2HCl  ZnCl2 + H2 79.1 g 79.1 g HCl 1 mol HCl 36.5 g Zn 1 mol H2 Other possibilities: Still starting with 79.1 grams of HCl, how many molecules of H2 gas are produced? Or what mass of H2 gas is produced? How would these questions change your calculations? Zn + 2HCl  ZnCl2 + H2 79.1 g ? mc Or ? g Same conversion to moles, same mole to mole ratio, different last conversions… 79.1 g HCl 1 mol HCl 36.5 g Zn 1 mol H2 2 mol HCl 6.02 x 1023 mc H2 1 mol H2 = 6.5 x 1023 mc H2 = 2.17 g H2