Chapter 8 The Mole

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

Contains 6.02 x particles 1 mole C = 6.02 x C atoms 1 mole H 2 O = 6.02 x H 2 O molecules 1 mole NaCl = 6.02 x Na + ions and 6.02 x Cl – ions A Moles of Particles

Moles of elements 1 mole Mg = 6.02 x Mg atoms 1 mole Au = 6.02 x Au atoms Moles of compounds 1 mole NH 3 = 6.02 x NH 3 molecules 1 mole C 9 H 8 O 4 = 6.02 x aspirin molecules Examples of Moles

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

Suppose we invented a new collection unit called a mep. One mep contains 8 objects. A. How many paper clips in 1 mep? 1) 12) 43) 8 B. How many oranges in 2.0 meps? 1) 42) 83) 16 C. How many meps in 40 gummy bears? 1) 52) 103) 20 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? 3) 8 B. How many oranges in 2.0 meps? 3) 16 C. How many meps in 40 gummy bears? 1) 5 Solution

1. Number of atoms in mole of Al 1) 500 Al atoms 2) 6.02 x Al atoms 3) 3.01 x Al atoms 2.Number of moles of S in 1.8 x S atoms 1) 1.0 mole S atoms 2) 3.0 mole S atoms 3) 1.1 x mole S atoms Learning Check

1. Number of atoms in mol of Al 3) 3.01 x Al atoms mol Al x 6.02 x Al atoms 1 mol Al 2. Number of moles of S if a sample of S contains 4.50 x S atoms 2) 3.0 mole S atoms 4.50 x S atoms x 1 mol S 6.02 x S atoms Solution

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 Molar Mass Determinatiom

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

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 Solution

Mass in grams of 1 mole equal numerically to the sum of the atomic masses 1 mole of CaCl 2 = g/mole (1 mole Ca x 40.1 g/mole) + (2 moles Cl x 35.5 g/mole) 1 mole of N 2 O 4 = 92.0 g/mole (2 moles N x 14.0 g/mole) + (4 moles O x 16.0 g/mole) Molar Mass of Compounds

A. 1 mole of K 2 O = ______g B. 1 mole of antacid Al(OH) 3 = ______g Learning Check

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

Prozac, C 17 H 18 F 3 NO, 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 Learning Check

Prozac, C 17 H 18 F 3 NO, 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) Solution

What is the percent carbon in C 5 H 8 NO 4 (MSG monosodium glutamate), a compound used to flavor foods and tenderize meats? 1) 8.22 %C 2) 24.3 %C 3) 41.1 %C Learning Check

Molar mass = g/mole % = total g C x 100 total g compound = 60.0 g C x 100 = 41.1% C g MSG Solution

Methane CH 4 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 CH 4 = 16.0 g 16.0 g CH 4 and 1 mole CH 4 1 mole CH g CH 4 Molar Mass Factors

Acetic acid CH 3 COOH is the acid in vinegar. It has a molar mass of 60.0 g/mole. 1 mole of acetic acid = ____________ 1 mole acetic acid or g acetic acid g acetic acid 1 mole acetic acid Learning Check

Acetic acid CH 3 COOH is the acid in vinegar. It has a molar mass of 60.0 g/mole. 1 mole of acetic acid = 60.0 g acetic acid 1 mole acetic acid or 60.0 g acetic acid 60.0 g acetic acid 1 mole acetic acid Solution

molar mass Grams Moles Calculations with Molar Mass

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 Moles and Grams

1. Molar mass of Al1 mole 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. Setup3.00 moles Al x 27.0 g Al 1 mole Al Answer = 81.0 g Al Mole Mass Conversions (grams moles)

The artificial sweetener aspartame (Nutri-Sweet) formula C 14 H 18 N 2 O 5 is used to sweeten diet foods, coffee and soft drinks. How many moles of aspartame are present in 225 g of aspartame? Learning Check

1. Molar mass of Aspartame C 14 H 18 N 2 O 5 (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 = mole aspartame Solution

Atomic Mass What is this number for Cl?? The atomic mass - the average mass of all the isotopes (diff atoms) that make up a sample of chlorine Chlorine consists of chlorine-35 and chlorine-37 in a 3:1 ratio Average Mass is an average based on the percents of each of the isotopes present

Atomic Mass Calculation Calculate the atomic mass of naturally occurring chlorine if 75.77% of chlorine atoms are chlorine-35 and 24.23% of chlorine atoms are chlorine-37 Step 1: convert the percentage to a decimal fraction: chlorine chlorine-37

Step 2 multiply the abundance, as a decimal, by the mass of that isotope. This is that isotope’s contribution to the atomic mass: For chlorine-35: x amu = amu For chlorine x amu = amu

Sum these partial weights to get the weighted average atomic mass of chlorine: amu amu = amu Step 3

Atomic Mass Determination Nitrogen consists of two naturally occurring isotopes 99.63% nitrogen-14 with a mass of amu 0.37% nitrogen-15 with a mass of amu What is the atomic mass of nitrogen?