Chapter 5 5.5 The Mole 5.6 Molar Mass 5.7 Mole Relationships in Chemical Equations 5.8 Mass Calculations for Reactions 1 Do Now… What is the molar mass of H20? Calculate how many grams of H20 are in 1 moles of H20. Calculate how many grams are in 5 moles of H20. 3pts 2 Objective I will be able to calculate the amount of product in a chemical equation 4 ouf of 5 times and demonstrate my knowledge of “Conservation of Mass”. 3 Agenda… Do now 10 min Lecture 30 min Handout 30 min Reading 30 min Achieve 3000 20 min 4 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 5 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 6 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 7 Avogadro’s Number 6.02 x 1023 particles 1 mole or 1 mole 6.02 x 1023 particles 8 Learning Check Suppose we invented a new collection unit called a mep. One mep contains 8 objects. A. How many paper clips in 1 mep? 1) 1 2) 4 3) 8 B. How many oranges in 2.0 meps? 1) 4 2) 8 3) 16 C. How many meps contain 40 gummy bears? 1) 5 2) 10 3) 20 9 Solution Suppose we invented a new collection unit called a mep. One mep contains 8 objects. A. How many paper clips in 1 mep? 3) 8 B. How many oranges in 2.0 meps? 3) 16 C. How many meps contain 40 gummy bears? 1) 5 10 Learning Check 1. Number of atoms in 0.500 mole of Al 1) 500 Al atoms 2) 6.02 x 1023 Al atoms 3) 3.01 x 1023 Al atoms 2.Number of moles of S in 1.8 x 1024 S atoms 1) 1.0 mole S atoms 2) 3.0 mole S atoms 3) 1.1 x 1048 mole S atoms 11 Solution 1. Number of atoms in 0.500 mol of Al 3) 3.01 x 1023 Al atoms 0.500 mol Al x 6.02 x 1023 Al atoms 1 mol Al 2. Number of moles of S if a sample of S contains 4.50 x 1024 S atoms 2) 3.0 mole S atoms 4.50 x 1024 S atoms x 1 mol S 6.02 x 1023 S atoms 12 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 13 Learning Check Give the molar mass to 0.1 g A. 1 mole of Br atoms = ________ B. 1 mole of Sn atoms = ________ 14 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 15 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 16 Learning Check A. 1 mole of K2O = ______g B. 1 mole of antacid Al(OH)3 = ______g 17 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 18 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 19 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) 20 Learning Check What is the percent carbon in C5H8NO4 (MSG monosodium glutamate), a compound used to flavor foods and tenderize meats? 1) 8.22 %C 2) 24.3 %C 3) 41.1 %C 21 Solution Molar mass = 146.0 g/mole % = total g C x 100 total g compound = 60.0 g C 146.0 g MSG x 100 = 41.1% C 22 Molar Mass Factors Methane CH4 known as natural gas is used in gas cook tops and gas heaters. Express the molar mass of methane in the form of conversion factors. Molar mass of CH4 = 16.0 g CH4 1 mole CH4 and 16.0 g 1 mole CH4 16.0 g CH4 23 Learning Check Acetic acid CH3COOH is the acid in vinegar . It has a molar mass of 60.0 g/mole. 1 mole of acetic acid = 1 mole acetic acid g acetic acid or ____________ g acetic acid 1 mole acetic acid 24 Calculating Mass of A Substance Balance equation Convert starting amount to moles Use coefficients to write a mol-mol factor Convert moles of desired to grams 25 Points to Remember 1. 2. 3. 4. Read an equation in moles Convert given amount to moles Use mole factor to give desired moles Convert moles to grams grams (given moles (given) grams (desired) moles (desired) 26 How to convert Moles to grams First set up the equation to see what your starting with and want to end with. Example: How many grams of oxygen are in 2.0 moles of O2? Set up: 2.0 moles O2 x 32.00 g O2 1.0 mole O2 = 64 g O2 27 Example: How many grams of hydrogen are in 12.0 moles of H2? Set up: 12.0 moles H2 x 1.01 g H2 1.0 mole H2 = 12 g H2 Remember sig figs 28 Solution Acetic acid CH3COOH is the acid in vinegar . It has a molar mass of 60.0 g/mole. 1 mole of acetic acid = 1 mole acetic acid 60.0 g acetic acid or 60.0 g acetic acid 60.0 g acetic acid 1 mole acetic acid 29 Example: How many grams of hydrogen are in 3.0 moles of H2O? Set up 3.0 mol H2O x 1.0 mol H2 x 1.01 g H2 1.0 mol H2O 1.0 mol H2 = 3.0 g H2 Remember sig figs 30 Calculations with Molar Mass molar mass Grams Moles 31 Moles and Grams Aluminum is often used for the structure of light-weight bicycle frames. How many grams of Al are in 3.00 moles of Al? 3.00 moles Al ? g Al 32 1. Molar mass of Al 1 mole Al = 27.0 g Al 2. Conversion factors for Al 27.0g Al 1 mol Al 3. Setup or 1 mol Al 27.0 g Al 3.00 moles Al Answer x 27.0 g Al 1 mole Al = 81.0 g Al 33 Learning Check The artificial sweetener aspartame (NutriSweet) formula C14H18N2O5 is used to sweeten diet foods, coffee and soft drinks. How many moles of aspartame are present in 225 g of aspartame? 34 Solution 1. 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 x 1 mole aspartame 294 g aspartame = 0.765 mole aspartame 35