Chapter 10 The Mole

National Standards for Chapter 10 UCP.1 Systems, order, and organization A.1 Abilities necessary to do scientific inquiry A.2 Understandings about scientific inquiry B.1 Structure of atoms B.2 Structure ad properties of matter B.3 Chemical reactions B.6 Interactions of energy and matter E.1 Abilities of technological design E.2 Understandings about science and technology F.5 Natural and human-induced hazards F.6 Science and technology in local, national, and global challenges G.1 Science as a human endeavor G.2 Nature of scientific knowledge G.3 Historical perspectives

Vocabulary/Study Guide Define each term using the Glossary Either write on the handout, or use your own paper This is due on Test Day (tentatively, Monday, March 31)

Section 1: Measuring Matter National Standards: UCP.1 Systems, order, and organization A.1 Abilities necessary to do scientific inquiry B.2 Structure ad properties of matter E.2 Understandings about science and technology G.2 Nature of scientific knowledge G.3 Historical perspectives

Objectives – Section 1 Explain how a mole is used to indirectly count the number of particles of matter. Relate the mole to a common everyday counting unit. Convert between moles and number of representative particles. REVIEW VOCABULARY: molecule: two or more atoms that covalently bond together to form a unit

New Vocabulary mole Avogadro’s number Chemists use the mole to count atoms, molecules, ions, and formula units.

Lab: How much is a mole? (pg. 318)

Counting Particles Chemists need a convenient method for accurately counting the number of atoms, molecules, or formula units of a substance. The mole is the SI base unit used to measure the amount of a substance. 1 mole is the amount of atoms in 12 g of pure carbon-12, or 6.02  1023 representative particles, which is any kind of particle – an atom, a molecule, a formula unit, an electron, an ion, etc. The number is called Avogadro’s number.

Converting Between Moles and Particles Conversion factors must be used. Moles to particles Number of molecules in 3.50 mol of sucrose

Converting Between Moles and Particles Particles to moles Use the inverse of Avogadro’s number as the conversion factor.

Converting Between Moles and Particles Practice Problems #1-4, page 323 Practice Problems #5-6, page 324

Mole Day Facts Fact 1- It is believed that one mole of paper if stacked can reach the moon more than 80 billion times. Fact 2- The second fact about one mole of grain of sand would be much more than that what is there at Miami Beach. Fact 3- The next fact about one mole is that one mole of blood cells would be more than the number of blood cells in every human-being on earth. Fact 4- It is also believed that one liter of water contains 55.5 moles of water. Fact 5- An astonishing fact about one mole is that one mole is approximately 1,616,434 light years or it can also be easily 8 times around our galaxy. Fact 6- Another interesting fact about one mole is that one mole of seconds is approximately 19 quadrillion years. It is 954,150 times the age of the universe or 4,240,666 times earth’s age. Fact 7- An important fact about one mole is that one mole of cents would be good enough to repay the debt of United States of America 86 million times.

Homework, Section 1 SECTION 1 REVIEW, Page 324 Questions #7-14 Answer with complete sentences Due tomorrow

Section 2: Mass and the Mole National Standards: UCP.1 Systems, order, and organization B.1 Structure of atoms B.2 Structure ad properties of matter E.2 Understandings about science and technology

Objectives – Section 2 Review Vocabulary: Relate the mass of an atom to the mass of a mole of atoms. Convert between number of moles and the mass of an element. Convert between number of moles and number of atoms of an element. Review Vocabulary: conversion factor: a ratio of equivalent values used to express the same quantity in different units

New Vocabulary molar mass A mole always contains the same number of particles; however, moles of different substances have different masses.

The Mass of a Mole 1 mol of copper (6.02 x 1023 atoms of copper) and 1 mol of carbon (6.02 x 1023 atoms of carbon) have different masses. One copper atom has a different mass than 1 carbon atom.

The Mass of a Mole Molar mass is the mass in grams of one mole of any pure substance. The molar mass of any element is numerically equivalent to its atomic mass and has the units g/mol.

Lab: Formulate a Model (pg. 326)

Using Molar Mass Moles to mass 3.00 moles of copper has a mass of 191 g.

Using Molar Mass Convert mass to moles with the inverse molar mass conversion factor. Convert moles to atoms with Avogadro’s number as the conversion factor.

Using Molar Mass Practice Problems #15-18, page 328

Math Skills Transparency 13

Using Molar Mass This figure shows the steps to complete conversions between mass and atoms.

Using Molar Mass Practice Problems #19-21, page 331

Homework, Section 2 SECTION 2 REVIEW, Page 332 Questions #22-28 Answer with complete sentences Due tomorrow

Section 3: Moles of Compounds National Standards: UCP.1 Systems, order, and organization B.2 Structure and properties of matter E.2 Understandings about science and technology

Objectives – Section 3 Review Vocabulary: Recognize the mole relationships shown by a chemical formula. Calculate the molar mass of a compound. Convert between the number of moles and mass of a compound. Apply conversion factors to determine the number of atoms or ions in a known mass of a compound. Review Vocabulary: representative particle: an atom, molecule, formula unit, or ion

New Vocabulary The molar mass of a compound can be calculated from its chemical formula and can be used to convert from mass to moles of that compound.

Chemical Formula and the Mole Chemical formulas indicate the numbers and types of atoms contained in one unit of the compound. One mole of CCl2F2 contains one mole of C atoms, two moles of Cl atoms, and two moles of F atoms.

Chemical Formulas and the Mole Practice Problems #29-33, page 335

The Molar Mass of Compounds The molar mass of a compound equals the molar mass of each element, multiplied by the moles of that element in the chemical formula, added together. The molar mass of a compound demonstrates the law of conservation of mass.

Molar Mass of Compounds Practice Problems #34-36, page 335

Math Skills Transparency 14: Calculating the Molar Mass of a Compound

Converting Moles of a Compound to Mass For elements, the conversion factor is the molar mass of the compound. The procedure is the same for compounds, except that you must first calculate the molar mass of the compound.

Converting Moles of a Compound to Mass Practice Problems #37-39, page 336

Converting the Mass of a Compound to Moles The conversion factor is the inverse of the molar mass of the compound.

Converting the Mass of a Compound to Moles Practice Problems #40-41, page 337

Converting the Mass of a Compound to Number of Particles Convert mass to moles of compound with the inverse of molar mass. Convert moles to particles with Avogadro’s number.

Converting the Mass of a Compound to Number of Particles Practice Problems #42-46, page 339

Converting the Mass of a Compound to Number of Particles This figure summarizes the conversions between mass, moles, and particles.

Transparency 34: Mass-to-Mole and Mole-to-Particles Conversions for Compounds

Lab: Estimating the Size of a Mole

Homework, Section 3 SECTION 3 REVIEW, Page 340 Questions #47-53 Answer with complete sentences Due tomorrow

Section 4: Empirical and Molecular Formulas National Standards: UCP.1 Systems, order, and organization A.1 Abilities necessary to do scientific inquiry A.2 Understandings about scientific inquiry B.2 Structure ad properties of matter E.2 Understandings about science and technology G.1 Science as a human endeavor

Objectives – Section 4 Review Vocabulary: Explain what is meant by the percent composition of a compound. Determine the empirical and molecular formulas for a compound from mass percent and actual mass data. Review Vocabulary: percent by mass: the ratio of the mass of each element to the total mass of the compound expressed as a percent

New Vocabulary percent composition empirical formula molecular formula A molecular formula of a compound is a whole-number multiple of its empirical formula.

Percent Composition The percent by mass of any element in a compound can be found by dividing the mass of the element by the mass of the compound and multiplying by 100.

Percent Composition The percent by mass of each element in a compound is the percent composition of a compound. Percent composition of a compound can also be determined from its chemical formula.

Mini-Lab: Analyze Chewing Gum, pg. 342

Percent Composition Practice Problems #54-57, page 344

Empirical Formula The empirical formula for a compound is the smallest whole-number mole ratio of the elements. You can calculate the empirical formula from percent by mass by assuming you have 100.00 g of the compound. Then, convert the mass of each element to moles. The empirical formula may or may not be the same as the molecular formula. Molecular formula of hydrogen peroxide = H2O2 Empirical formula of hydrogen peroxide = HO

Empirical Formula Practice Problems #58-61, page 346

Molecular Formula The molecular formula specifies the actual number of atoms of each element in one molecule or formula unit of the substance. Molecular formula is always a whole-number multiple of the empirical formula.

Molecular Formula

Molecular Formula Practice Problems #62-66, page 350

Lab: Mole Ratios

Molecular Formula Worksheet: Supplemental Problems

Homework, Section 4 SECTION 4 REVIEW, Page 350 Questions #67-73 Answer with complete sentences Due tomorrow

Section 5: Formulas of Hydrates National Standards: UCP.1 Systems, order, and organization A.1 Abilities necessary to do scientific inquiry A.2 Understandings about scientific inquiry B.2 Structure ad properties of matter B.3 Chemical reactions B.6 Interactions of energy and matter E.1 Abilities of technological design E.2 Understandings about science and technology F.5 Natural and human-induced hazards F.6 Science and technology in local, national, and global challenges

Objectives – Section 5 Explain what a hydrate is and relate the name of the hydrate to its composition. Determine the formula of a hydrate from laboratory data. Review Vocabulary: crystal lattice: a three-dimensional geometric arrangement of particles

New Vocabulary hydrate Hydrates are solid ionic compounds in which water molecules are trapped.

Naming Hydrates A hydrate is a compound that has a specific number of water molecules bound to its atoms. The number of water molecules associated with each formula unit of the compound is written following a dot. Sodium carbonate decahydrate = Na2CO3 • 10H2O

Naming Hydrates

Analyzing a Hydrate When heated, water molecules are released from a hydrate leaving an anhydrous compound. To determine the formula of a hydrate, find the number of moles of water associated with 1 mole of hydrate.

Analyzing a Hydrate Weigh hydrate. Heat to drive off the water. Weigh the anhydrous compound. Subtract and convert the difference to moles. The ratio of moles of water to moles of anhydrous compound is the coefficient for water in the hydrate.

Analyzing a Hydrate Practice Problems #74-75, page 353

Lab: Determine the Formula of a Hydrate, page 356

Use of Hydrates Anhydrous forms of hydrates are often used to absorb water, particularly during shipment of electronic and optical equipment. In chemistry labs, anhydrous forms of hydrates are used to remove moisture from the air and keep other substances dry.

Homework, Section 5 SECTION 5 REVIEW, Page 354 Questions #76-82 Answer with complete sentences Due tomorrow

Key Concepts The mole is a unit used to count particles of matter indirectly. One mole of a pure substance contains Avogadro’s number of particles. Representative particles include atoms, ions, molecules, formula units, electrons, and other similar particles. One mole of carbon-12 atoms has a mass of exactly 12 g. Conversion factors written from Avogadro’s relationship can be used to convert between moles and number of representative particles.

Key Concepts The mass in grams of 1 mol of any pure substance is called its molar mass. The molar mass of an element is numerically equal to its atomic mass. The molar mass of any substance is the mass in grams of Avogadro’s number of representative particles of the substance. Molar mass is used to convert from moles to mass. The inverse of molar mass is used to convert from mass to moles.

Key Concepts Subscripts in a chemical formula indicate how many moles of each element are present in 1 mol of the compound. The molar mass of a compound is calculated from the molar masses of all of the elements in the compound. Conversion factors based on a compound’s molar mass are used to convert between moles and mass of a compound.

Key Concepts The percent by mass of an element in a compound gives the percentage of the compound’s total mass due to that element. The subscripts in an empirical formula give the smallest whole-number ratio of moles of elements in the compound. The molecular formula gives the actual number of atoms of each element in a molecule or formula unit of a substance. The molecular formula is a whole-number multiple of the empirical formula.

Key Concepts The formula of a hydrate consists of the formula of the ionic compound and the number of water molecules associated with one formula unit. The name of a hydrate consists of the compound name and the word hydrate with a prefix indicating the number of water molecules in 1 mol of the compound. Anhydrous compounds are formed when hydrates are heated.