Chapter 7. Bellringer. Table of Contents. Chapter 7. Chapter 7. Objectives. Avogadro s Number and the Mole. Chapter 7. Chapter 7


 Irene Cox
 1 years ago
 Views:
Transcription
1 The Mole and Chemical Table of Contents Chemical Formulas Bellringer List as many common counting units as you can. Determine how many groups of each unit in your list are present in each of the following amounts: 500 goldfish 150 unicycles 50 jet planes Objectives Identify the mole as the unit used to count particles, whether atoms, ions, or molecules. Use Avogadro s number to convert between amount in moles and number of particles. Solve problems converting between mass, amount in moles, and number of particles using Avogadro s number and molar mass. Avogadro s Number and the Mole The SI unit for amount is called the mole (mol). A mole is the number of atoms in exactly 12 grams of carbon12. Scientists use the mole to make counting large numbers of particles easier. The number of particles in a mole is called Avogadro s Number. Avogadro s number is units/mole. Visual Concepts Avogadro s Number and the Mole, continued The Mole Is a Counting Unit The mole is used to count out a given number of particles, whether they are atoms, molecules, formula units, ions, or electrons. The Mole The mole is just one kind of counting unit: 1 dozen = 12 objects 1 hour = 3600 seconds 1 mole = particles
2 Avogadro s Number and the Mole, continued Amount in Moles Can Be Converted to Number of Particles Counting units are used to make conversion factors. The definition of one mole is The conversion factor is particles = 1 mol particles 1mol = 1 Avogadro s Number and the Mole, continued Choose the Conversion Factor That Cancels the Given Units All conversion factors are equal to 1, so you can use them to convert among different units. You can tell which conversion factor to use, because the needed conversion factor should cancel the units of the given quantity to give you the units of the answer or the unknown quantity. Converting Between Amount in Moles and Number of Particles Converting Amount in Moles to Number of Particles Sample Problem A Find the number of molecules in 2.5 mol of sulfur dioxide. Converting Amount in Moles to Number of Particles Sample Problem A Solution 2.5 mol SO 2? =? molecules SO 2 You are converting from the unit mol to the unit molecules. The conversion factor must have the units of molecules/mol. You use molecules/1 mol. Converting Amount in Moles to Number of Particles Sample Problem A Solution, continued 2.5 mol SO 2? =? molecules SO molecules SO2 2.5 mol SO =? molecules SO 1 mol SO mol SO 2 = molecules SO 2
3 Avogadro s Number and the Mole, continued Number of Particles Can Be Converted to Amount in Moles The reverse calculation is similar to that in Sample Problem A but the conversion factor is inverted to get the correct units in the answer. example: How many moles are iron(iii) ions? Converting Number of Particles to Amount in Moles Sample Problem B A sample contains molecules of sulfur dioxide, SO 2. Determine the amount in moles ions Fe 3+ 1molFe ions Fe mol Fe + = Converting Number of Particles to Amount in Moles Sample Problem B Solution Converting Number of Particles to Amount in Moles Sample Problem B Solution, continued molecules SO 2? =? mol SO 2 You are converting from the unit molecules to the unit mol. The conversion factor must have the units of mol/molecules. You use 1 mol/ molecules molecules SO 2? =? mol SO molecules SO 1molSO molecules SO =? mol SO molecules SO 2 = mol SO 2 2 Visual Concepts Molar Mass Relates Moles to Grams Amount in Moles Can Be Converted to Mass The molar mass is the mass in grams of one mole of an element or compound. Molar Mass Molar mass is numerically equal to the atomic mass of monatomic elements and the formula mass of compounds and diatomic elements. The units for molar mass are g/mol. Molar mass can be used as a conversion factor in problems converting between mass and amount.
4 Visual Concepts Molar Mass as a Conversion Factor Molar Mass Relates Moles to Grams, continued The Mole Plays a Central Part in Chemical Conversions To convert from number of particles to mass, you must use a twopart process: First, convert number of particles to amount in moles. Second, convert amount in moles to mass in grams. One step common to many problems in chemistry is converting to amount in moles. Converting Between Mass, Amount, and Number of Particles Converting Number of Particles to Mass Sample Problem C Find the mass in grams of atoms of carbon, whose molar mass is g/mol. Converting Number of Particles to Mass Sample Problem C Solution First part: atoms? =? mol Select the conversion factor that will take you from number of atoms to amount in moles. You use 1 mol/ atoms. Converting Number of Particles to Mass Sample Problem C Solution, continued Second part:? mol? =? g Select the conversion factor that will take you from amount in moles to mass in grams. You use the molar mass of carbon, g C/1 mol.
5 Converting Number of Particles to Mass Sample Problem C Solution, continued 24 1 mol g C atoms atoms 1 mol = 48.7 g C Molar Mass Relates Moles to Grams, continued Mass Can Be Converted to Amount in Moles Converting from mass to number of particles is the reverse of the operation in the previous problem. To convert from mass to number of particles, you must use a twopart process: First, convert mass in grams to amount in moles. Second, convert amount in moles to number of particles. Converting Mass to Number of Particles Sample Problem D Find the number of molecules present in 47.5 g of glycerol, C 3 H 8 O 3. The molar mass of glycerol is g/mol. Converting Mass to Number of Particles Sample Problem D Solution First part: 47.5 g? =? mol Select the conversion factor that will take you from mass in grams to amount in moles. You use the inverse of the molar mass of glycerol: 1mol g C H O Converting Mass to Number of Particles Sample Problem D Solution, continued Second part:? mol? =? molecules Select the conversion factor that will take you from amount in moles to number of particles molecules You use 1mol. Converting Mass to Number of Particles Sample Problem D Solution, continued 23 1 mol molecules 47.5 g C3H8O g C 3 H 8 O 3 1 mol = molecules
6 Molar Mass Relates Moles to Grams, continued Remember to Round Consistently Remember that an answer must never be given to more significant figures than is appropriate. Round molar masses from the periodic table to two significant figures to the right of the decimal point. Bellringer Compare the masses of a roll of pennies and a roll of dimes. Both contain 50 coins. Why are the masses of the rolls different when both rolls contain the same number of coins? If given a roll of mixed coins, what information would you need to determine the mass of the roll? Objectives Use a periodic table or isotopic composition data to determine the average atomic masses of elements. Infer information about a compound from its chemical formula. Determine the molar mass of a compound from its formula. Average Atomic Mass and the Periodic Table Most Elements are a Mixture of Isotopes Isotopes are atoms that have different numbers of neutrons than other atoms of the same element do. Average atomic mass is a weighted average of the atomic mass of an element s isotopes. If you know the abundance of each isotope, you can calculate the average atomic mass of an element. Visual Concepts Average Atomic Mass Calculating Average Atomic Mass Sample Problem E The mass of a Cu63 atom is amu, and that of a Cu65 atom is amu. Using the data below, find the average atomic mass of copper. abundance of Cu63 = 69.17% abundance of Cu65 = 30.83%
7 Calculating Average Atomic Mass Sample Problem E Solution The contribution of each isotope is equal to its atomic mass multiplied by the fraction of that isotope. contribution of Cu63: amu contribution of Cu65: amu Average atomic mass is the sum of the individual contributions: (62.94 amu ) + (64.93 amu ) = amu and Moles Formulas Express A compound s chemical formula tells you which elements, as well as how much of each, are present in a compound. Formulas for covalent compounds show the elements and the number of atoms of each element in a molecule. Formulas for ionic compounds show the simplest ratio of cations and anions in any pure sample. and Moles, continued Formulas Express, continued Any sample of compound has many atoms and ions, and the formula gives a ratio of those atoms or ions. and Moles, continued Formulas Give Ratios of Polyatomic Ions Formulas for polyatomic ions show the simplest ratio of cations and anions. They also show the elements and the number of atoms of each element in each ion. For example, the formula KNO 3 indicates a ratio of one K + cation to one NO 3 anion. Understanding Formulas for Polyatomic Ionic Compounds and Moles, continued Formulas Are Used to Calculate Molar Masses The molar mass of a molecular compound is the sum of the masses of all the atoms in the formula expressed in g/mol. The molar mass of an ionic compound is the sum of the masses of all the atoms in the formula expressed in g/mol.
8 Visual Concepts Formula Mass Calculating Molar Mass for Ionic Compounds Calculating Molar Mass of Compounds Sample Problem F Find the molar mass of barium nitrate, Ba(NO 3 ) 2. Calculating Molar Mass of Compounds Sample Problem F Solution Find the # of moles of each element in 1 mol Ba(NO 3 ) 2 : Each mole has 1 mol Ba, 2 mol N, and 6 mol O. Use the periodic table to find the molar mass of each element in the formula: molar mass of Ba: g/mol; molar mass of N: g/mol and molar mass of O: g/mol Calculating Molar Mass of Compounds Sample Problem F Solution, continued Multiply the molar mass of each element by the number of moles of each element. Add these masses to get the total molar mass of Ba(NO 3 ) 2. mass of 1 mol Ba = g/mol = g/mol mass of 2 mol N = g/mol = g/mol + mass of 6 mol O = g/mol = g/mol Bellringer Brainstorm a list of what you know about percentages. molar mass of Ba(NO 3 ) 2 = g/mol
9 Objectives Determine a compound s empirical formula from its percentage composition. Determine the molecular formula or formula unit of a compound from its empirical formula and its formula mass. Calculate percentage composition of a compound from its molecular formula or formula unit. Using Analytical Data The percentage composition is the percentage by mass of each element in a compound. Percentage composition helps verify a substance s identity. Percentage composition also can be used to compare the ratio of masses contributed by the elements in two different substances. Percentage of Iron Oxides Using Analytical Data, continued Determining Empirical Formulas An empirical formula is a chemical formula that shows the simplest ratio for the relative numbers and kinds of atoms in a compound. An actual formula shows the actual ratio of elements or ions in a single unit of a compound. For example, the empirical formula for ammonium nitrate is NH 2 O, while the actual formula is NH 4 NO 2. Empirical and Actual Formulas Using Analytical Data, continued Determining Empirical Formulas, continued You can use the percentage composition for a compound to determine its empirical formula. 1. Convert the percentage of each element to g. 2. Convert from g to mol using the molar mass of each element as a conversion factor. 3. Compare these amounts in mol to find the simplest wholenumber ratio among the elements.
10 Visual Concepts Percentage Determining an Empirical Formula from Percentage Sample Problem G Chemical analysis of a liquid shows that it is 60.0% C, 13.4% H, and 26.6% O by mass. Calculate the empirical formula of this substance. Determining an Empirical Formula from Percentage Sample Problem G Solution Assume that you have a g sample, and convert the percentages to grams. for C: for H: for O: 60.0% g = 60.0 g C 13.4% g = 13.4 g H 26.6% g = 26.6 g O Determining an Empirical Formula from Percentage Sample Problem G Solution, continued Convert the mass of each element into the amount in moles, using the reciprocal of the molar mass. 1molC 60.0gC 5.00molC g C = 1molH 13.4 g H 13.3 mol H 1.01 g H = 1molO 26.6 g O 1.66 mol O g O = Determining an Empirical Formula from Percentage Sample Problem G Solution, continued The formula can be written as C 5 H 13.3 O 1.66, but you divide by the smallest subscript to get whole numbers mol C mol H mol O 1.66 = 3.01 mol C = 8.01 mol H = 1.00 mol O The empirical formula is C 3 H 8 O. Using Analytical Data, continued Molecular Formulas Are Multiples of Empirical Formulas The formula for an ionic compound shows the simplest wholenumber ratio of the large numbers of ions in a crystal of the compound. A molecular formula is a wholenumber multiple of the empirical formula. The molar mass of any compound is equal to the molar mass of the empirical formula times a whole number, n.
11 Visual Concepts Comparing Molecular and Empirical Formulas Determining a Molecular Formula from an Empirical Formula Sample Problem H The empirical formula for a compound is P 2 O 5. Its experimental molar mass is 284 g/mol. Determine the molecular formula of the compound. Determining a Molecular Formula from an Empirical Formula Sample Problem H Solution Determining a Molecular Formula from an Empirical Formula Sample Problem H Solution, continued Find the molar mass of the empirical formula P 2 O 5. 2 molar mass of P = g/mol + 5 molar mass of O = g/mol molar mass of P 2 O 5 = g/mol n = experimental molar mass of compound molar mass of empirical formula 284 g/mol n = = g/mol n (empirical formula) = 2 (P 2 O 5 ) = P 4 O 10 Using Analytical Data, continued Can Give Percentage If you know the chemical formula of any compound, then you can calculate the percentage composition. Using Analytical Data, continued Can Give Percentage CO and CO 2 are both made up of C and O, but they have different percentage compositions. From the subscripts, determine the mass contributed by each element and add these to get molar mass. Divide the mass of each element by the molar mass. Multiply by 100 to find the percentage composition of that element.
12 Using a Chemical Formula to Determine Percentage Sample Problem I Calculate the percentage composition of copper(i) sulfide, Cu 2 S, a copper ore called chalcocite. Using a Chemical Formula to Determine Percentage Sample Problem I Solution Find the molar mass of Cu 2 S. 2 mol g Cu/mol = g Cu + 1 mol g S/mol = g S molar mass of Cu 2 S = g/mol Using a Chemical Formula to Determine Percentage Sample Problem I Solution, continued Calculate the fraction that each element contributes to the total mass by substituting the masses into the equations below and rounding correctly. mass of 2 mol Cu mass % Cu = 100 = molar mass of Cu S g Cu 100 = Cu S % Cu Using a Chemical Formula to Determine Percentage Sample Problem I Solution, continued mass of 1 mol S mass % S = 100 = molar mass of Cu S g S 100 = g Cu S % S 1. Element A has two isotopes. One has an atomic mass of 120 and constitutes 60%; the other has an atomic mass of 122 and constitutes 40%. Which range below includes the average atomic mass of Element A? A. less than 120 B. between 120 and 121 C. between 121 and 122 D. greater than Element A has two isotopes. One has an atomic mass of 120 and constitutes 60%; the other has an atomic mass of 122 and constitutes 40%. Which range below includes the average atomic mass of Element A? A. less than 120 B. between 120 and 121 C. between 121 and 122 D. greater than 122
13 2. Which of the following can be determined from the empirical formula of a compound alone? F. the true formula of the compound G. the molecular mass of the compound H. the percentage composition of the compound I. the arrangement of atoms within a molecule of the compound 2. Which of the following can be determined from the empirical formula of a compound alone? F. the true formula of the compound G. the molecular mass of the compound H. the percentage composition of the compound I. the arrangement of atoms within a molecule of the compound 3. How many ions are in 0.5 moles of NaCl? A B C D How many ions are in 0.5 moles of NaCl? A B C D How many moles of calcium (mass = 40.1) are in a serving of milk containing 290 mg of calcium? 4. How many moles of calcium (mass = 40.1) are in a serving of milk containing 290 mg of calcium? Answer: mol
14 5. How is Avogadro's number related to moles? 5. How is Avogadro's number related to moles? Answer: Avogadro's number is the number of particles in a mole. 6. Antimony has two isotopes. One, amounting to 57.3% of the atoms, has a mass of amu. The other, 42.7% of the atoms, has a mass of amu. What is the average atomic mass of antimony? 6. Antimony has two isotopes. One, amounting to 57.3% of the atoms, has a mass of amu. The other, 42.7% of the atoms, has a mass of amu. What is the average atomic mass of antimony? Answer: amu Reading Skills Read the passage below. Then answer the questions. In 1800 two English chemists, Nicholson and Carlisle, discovered that when an electric current is passed through water, hydrogen and oxygen were produced in a 2:1 volume ratio and a 1:8 mass ratio. This evidence helped to support John Dalton's theory that matter consisted of atoms, demonstrating that water consists of the two elements in a constant proportion. If the same number of moles of each gas occupy the same volume, then each molecule of water must consist of twice as much hydrogen as oxygen, even though the mass of hydrogen is only oneeighth that of oxygen. Reading Skills 7. Based on this experiment, what is the empirical formula of water? F. HO G. H 2 O H. H 2 O 8 I. O 8 H
15 Reading Skills 7. Based on this experiment, what is the empirical formula of water? F. HO G. H 2 O H. H 2 O 8 I. O 8 H Reading Skills 8. How would the experimental result have been different if hydrogen gas existed as individual atoms while oxygen formed molecules with two atoms bound by a covalent bond? A. The result would be the same. B. The ratio of hydrogen to oxygen would be 1:1. C. The ratio of hydrogen to oxygen would be 1:4. D. The ratio of hydrogen to oxygen would be 4:1. Reading Skills 8. How would the experimental result have been different if hydrogen gas existed as individual atoms while oxygen formed molecules with two atoms bound by a covalent bond? Reading Skills 9. How does the empirical formula for water compare to its molecular formula? A. The result would be the same. B. The ratio of hydrogen to oxygen would be 1:1. C. The ratio of hydrogen to oxygen would be 1:4. D. The ratio of hydrogen to oxygen would be 4:1. Reading Skills 9. How does the empirical formula for water compare to its molecular formula? Use the diagram below to answer questions Answer: Both formulas are the same, H 2 O.
16 10.How many moles of oxygen atoms are there in moles of carbon dioxide? F G H I How many moles of oxygen atoms are there in moles of carbon dioxide? F G H I Explain why the percentage of oxygen in carbon dioxide is not twice the percentage of oxygen in carbon monoxide, if there are twice as many oxygen atoms. 11.Explain why the percentage of oxygen in carbon dioxide is not twice the percentage of oxygen in carbon monoxide, if there are twice as many oxygen atoms. Answer: Although there are twice as many oxygen atoms in carbon dioxide, the percentage composition is based on the mass, not the number of atoms. 12.If you did not know the true formulas for carbon monoxide and carbon dioxide, what information would you need beyond what is provided in the illustration in order to calculate them? A. the percentage compositions B. the atomic masses of carbon and oxygen C. the melting and boiling points of each compound D. the number of atoms of each element in the compound 12.If you did not know the true formulas for carbon monoxide and carbon dioxide, what information would you need beyond what is provided in the illustration in order to calculate them? A. the percentage compositions B. the atomic masses of carbon and oxygen C. the melting and boiling points of each compound D. the number of atoms of each element in the compound
17 13.How many grams of carbon are contained in grams of carbon dioxide? F G H I How many grams of carbon are contained in grams of carbon dioxide? F G H I
Chapter 7. Chapter 7. Chemical Formulas Express Composition. Chapter 7 MARCH REVIEW SLIDES LISTEN AND UPDATE MISSING NOTES
REVIEW Express A compound s chemical formula tells you which elements, & how much of each, are present in a compound. Formulas for covalent compounds show the elements and the number of atoms of each element
More informationCHAPTER. Copyright by Holt, Rinehart and Winston. All rights reserved.
CHAPTER 222 Galaxies have hundreds of billions of stars. The universe may have as many as sextillion stars that s 1000 000 000 000 000 000 000 (or 1 10 21 ) stars. Such a number is called astronomical
More informationStudy Guide For Chapter 7
Name: Class: Date: ID: A Study Guide For Chapter 7 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The number of atoms in a mole of any pure substance
More informationHow much does a single atom weigh? Different elements weigh different amounts related to what makes them unique.
How much does a single atom weigh? Different elements weigh different amounts related to what makes them unique. What units do we use to define the weight of an atom? amu units of atomic weight. (atomic
More informationElement of same atomic number, but different atomic mass o Example: Hydrogen
Atomic mass: p + = protons; e  = electrons; n 0 = neutrons p + + n 0 = atomic mass o For carbon12, 6p + + 6n 0 = atomic mass of 12.0 o For chlorine35, 17p + + 18n 0 = atomic mass of 35.0 atomic mass
More informationCHAPTER 11  CHEMICAL QUANTITIES
I. THE MOLE CONCEPT CHAPTER 11  CHEMICAL QUANTITIES A. What is a mole? 1. a mole is the SI unit of measurement of counting; just like a dozen is a measurement 2. a mole is a number a. 6.02 x 10 23 is
More informationChemistry I: Using Chemical Formulas. Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu.
Chemistry I: Using Chemical Formulas Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu. Molar Mass  The mass in grams of 1 mole of a substance. Substance
More informationTOPIC 8. CHEMICAL CALCULATIONS II: % composition, empirical formulas.
TOPIC 8. CHEMICAL CALCULATIONS II: % composition, empirical formulas. Percentage composition of elements in compounds. In Topic 1 it was stated that a given compound always has the same composition by
More informationChapter 7 Part II: Chemical Formulas and Equations. Mr. Chumbley Chemistry 12
Chapter 7 Part II: Chemical Formulas and Equations Mr. Chumbley Chemistry 12 SECTION 3: USING CHEMICAL FORMULAS Molecules and Formula Unit We have not yet discussed the different ways in which chemical
More informationChapter 4. Chemical Composition. Chapter 4 Topics H 2 S. 4.1 Mole Quantities. The Mole Scale. Molar Mass The Mass of 1 Mole
Chapter 4 Chemical Composition Chapter 4 Topics 1. Mole Quantities 2. Moles, Masses, and Particles 3. Determining Empirical Formulas 4. Chemical Composition of Solutions Copyright The McGrawHill Companies,
More informationTOPIC 8. CHEMICAL CALCULATIONS II: % composition, empirical formulas.
TOPIC 8. CHEMICAL CALCULATIONS II: % composition, empirical formulas. Percentage composition of elements in compounds. In Topic 1 it was stated that a given compound always has the same composition by
More informationCHEMICAL QUANTITIES. Chapter 10
CHEMICAL QUANTITIES Chapter 10 What is a mole? A unit of measurement in chemistry 1 mole of a substance = 6.02 x 10 23 (Avagadro s number) representative particles of a substance Representative particle
More informationChapter 10 Chemical Quantities
Chapter 10 Chemical Quantities 101 The Mole: A Measurement 102 MoleMass and MoleVolume Relationships 103 Percent Composition and Chemical Formulas 1 Copyright Pearson Education, Inc, or its affiliates
More informationChapter 3. Stoichiometry: Ratios of Combination. Insert picture from First page of chapter. Copyright McGrawHill 2009 1
Chapter 3 Insert picture from First page of chapter Stoichiometry: Ratios of Combination Copyright McGrawHill 2009 1 3.1 Molecular and Formula Masses Molecular mass  (molecular weight) The mass in amu
More information3 large lures x 22.0 g/lure + 5 medium lures x 12.9 g/lure + 5 small lures x 8.5 g/lure g packaging = g
Answers additional questions 7.1 1. Describe how the particles of sodium bromide, an ionic compound, are different from water, a covalent compound. Give the particle name of each compound type. Ionic compounds
More informationMASS RELATIONS IN CHEMISTRY; STOICHIOMETRY
MASS RELATIONS IN CHEMISTRY; STOICHIOMETRY [MH5; Ch. 3] Each element has its own unique mass. The mass of each element is found on the Periodic Table under the chemical symbol for the element (it is usually
More informationChemical Calculations: The Mole Concept and Chemical Formulas. AW Atomic weight (mass of the atom of an element) was determined by relative weights.
1 Introduction to Chemistry Atomic Weights (Definitions) Chemical Calculations: The Mole Concept and Chemical Formulas AW Atomic weight (mass of the atom of an element) was determined by relative weights.
More informationCHAPTER 8: CHEMICAL COMPOSITION
CHAPTER 8: CHEMICAL COMPOSITION Active Learning: 14, 68, 12, 1825; EndofChapter Problems: 34, 982, 8485, 8792, 94104, 107109, 111, 113, 119, 125126 8.2 ATOMIC MASSES: COUNTING ATOMS BY WEIGHING
More informationCh. 10 The Mole I. Molar Conversions
Ch. 10 The Mole I. Molar Conversions I II III IV A. What is the Mole? A counting number (like a dozen) Avogadro s number (N A ) 1 mole = 6.022 10 23 representative particles B. Mole/Particle Conversions
More informationThe mass of the formula unit is called the formula mass Formula masses are calculated the same way as molecular masses
Chapter 4: The Mole Atomic mass provides a means to count atoms by measuring the mass of a sample The periodic table on the inside cover of the text gives atomic masses of the elements The mass of an atom
More informationChemical Reactions. Chemical Equations. Mole as Conversion Factor: To convert between number of particles and an equivalent number of moles:
Quantities of Reactants and Products CHAPTER 3 Chemical Reactions Stoichiometry Application of The Law of Conservation of Matter Chemical bookkeeping Chemical Equations Chemical equations: Describe proportions
More informationChapter 3. Molecules, Compounds, and Chemical Composition
Chapter 3 Molecules, Compounds, and Chemical Composition Elements and Compounds Elements combine together to make an almost limitless number of compounds. The properties of the compound are totally different
More informationCHAPTER 3 STOICHIOMETRY OF FORMULAS AND EQUATIONS
CHAPTER 3 STOICHIOMETRY OF FORMULAS AND EQUATIONS FOLLOW UP PROBLEMS 3.1A Plan: The mass of carbon must be changed from mg to g. The molar mass of carbon can then be used to determine the number of moles.
More informationThe Mole. 6.022 x 10 23
The Mole 6.022 x 10 23 Background: atomic masses Look at the atomic masses on the periodic table. What do these represent? E.g. the atomic mass of Carbon is 12.01 (atomic # is 6) We know there are 6 protons
More information2 The Structure of Atoms
CHAPTER 4 2 The Structure of Atoms SECTION Atoms KEY IDEAS As you read this section, keep these questions in mind: What do atoms of the same element have in common? What are isotopes? How is an element
More informationChapter 4 Chemical Composition
Chapter 4 Chemical Composition 4.1 (a) mole; (b) Avogadro s number; (c) empirical formula; (d) solute; (e) molarity; (f) concentrated solution 4. (a) molar mass; (b) percent composition by mass; (c) solvent;
More informationINTRODUCTORY CHEMISTRY Concepts and Critical Thinking
INTRODUCTORY CHEMISTRY Concepts and Critical Thinking Sixth Edition by Charles H. Corwin Chapter 9 The Mole Concept by Christopher Hamaker 2011 Pearson Education, Inc. Chapter 9 1 Avogadro s Number Avogadro
More informationChapter 4 Chemical Composition. Moles of Various Elements and Compounds Figure 4.8
Chapter 4 Chemical Composition Mole Quantities Moles, Masses, and Particles Determining Empirical and Molecular Formulas Chemical Composition of Solutions 41 Copyright The McGrawHill Companies, Inc.
More informationThe Mole Concept and Atoms
Copyright The McGrawHill Companies, Inc. Permission required for reproduction or display. Chapter 4 24 September 2013 Calculations and the Chemical Equation The Mole Concept and Atoms Atoms are exceedingly
More informationFormulas, Equations, and Moles. + "reacts with" "to produce" Equations must be balanced. Equal amounts of each element on each side of the equation.
Chapter 3 Formulas, Equations, and Moles Chemical Equations 2 2 + 2 2 2 reactants products + "reacts with" "to produce" coefficients  indicate amount of substance Equations must be balanced. Equal amounts
More informationChemical Composition. Introductory Chemistry: A Foundation FOURTH EDITION. Atomic Masses. Atomic Masses. Atomic Masses. Chapter 8
Introductory Chemistry: A Foundation FOURTH EDITION by Steven S. Zumdahl University of Illinois Chemical Composition Chapter 8 1 2 Atomic Masses Balanced equation tells us the relative numbers of molecules
More information1. How many hydrogen atoms are in 1.00 g of hydrogen?
MOLES AND CALCULATIONS USING THE MOLE CONCEPT INTRODUCTORY TERMS A. What is an amu? 1.66 x 1024 g B. We need a conversion to the macroscopic world. 1. How many hydrogen atoms are in 1.00 g of hydrogen?
More informationThe Mole Concept. The Mole. Masses of molecules
The Mole Concept Ron Robertson r2 c:\files\courses\111020\2010 final slides for web\mole concept.docx The Mole The mole is a unit of measurement equal to 6.022 x 10 23 things (to 4 sf) just like there
More informationPart One: Mass and Moles of Substance. Molecular Mass = sum of the Atomic Masses in a molecule
CHAPTER THREE: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS Part One: Mass and Moles of Substance A. Molecular Mass and Formula Mass. (Section 3.1) 1. Just as we can talk about mass of one atom of
More informationUseful only for measuring the mass of very small objects atoms and molecules!
Chapter 9 Chemical Composition (Moles) Which weighs more, 1 atom of He or 1 atom of O? Units of mass: Pound Kilogram Atomic mass unit (AMU) There are others! 1 amu = 1.66 x 1024 grams = mass of a proton
More informationMajor chemistry laws. Mole and Avogadro s number. Calculating concentrations.
Major chemistry laws. Mole and Avogadro s number. Calculating concentrations. Major chemistry laws Avogadro's Law Equal volumes of gases under identical temperature and pressure conditions will contain
More informationSection 6.6: The Composition of Unknown Compounds
Section 6.6: The Composition of Unknown Compounds Tutorial 1 Practice, page 286 1. Given: = 4.60 g ; m N = 1.40 g Required: percentage of each element: % N; % O Step 1. Use the percentage formula to calculate
More informationCalculating Atoms, Ions, or Molecules Using Moles
TEKS REVIEW 8B Calculating Atoms, Ions, or Molecules Using Moles TEKS 8B READINESS Use the mole concept to calculate the number of atoms, ions, or molecules in a sample TEKS_TXT of material. Vocabulary
More informationMatter. Atomic weight, Molecular weight and Mole
Matter Atomic weight, Molecular weight and Mole Atomic Mass Unit Chemists of the nineteenth century realized that, in order to measure the mass of an atomic particle, it was useless to use the standard
More informationChem. Ch. 10 ~ THE MOLE NOTE: Vocabulary terms are in boldface and underlined. Supporting details are in italics.
Chem. Ch. 10 ~ THE MOLE NOTE: Vocabulary terms are in boldface and underlined. Supporting details are in italics. 10.1 Notes I. Measuring Matter A. SI unit of chemical quantity = the mole (abbreviated
More informationPercent composition (mass percent, percent composition by mass)
Percent composition (mass percent, percent composition by mass) Mass % = mass of component in substance (grams) x 100 mass of substance (grams) What is the mass % composition of water? MM (H 2 O) = 18.0152
More information10 The Mole. Section 10.1 Measuring Matter
Name Date Class The Mole Section.1 Measuring Matter In your textbook, read about counting particles. In Column B, rank the quantities from Column A from smallest to largest. Column A Column B 0.5 mol 1.
More informationThe Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon12? Molar Mass of Atoms 3/1/2015
The Mole Chapter 10 1 Objectives Use the mole and molar mass to make conversions among moles, mass, and number of particles Determine the percent composition of the components of a compound Calculate empirical
More informationChemical Quantities: The Mole Chapter 7 Assignment & Problem Set
Chemical Quantities: The Mole Name WarmUps (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Chemical Quantities: The Mole 2 Study Guide: Things You Must Know
More informationChapter 1: Moles and equations. Learning outcomes. you should be able to:
Chapter 1: Moles and equations 1 Learning outcomes you should be able to: define and use the terms: relative atomic mass, isotopic mass and formula mass based on the 12 C scale perform calculations, including
More informationCHAPTER 3 MASS RELATIONSHIPS IN CHEMICAL REACTIONS
CHAPTER 3 MASS RELATIONSHIPS IN CHEMICAL REACTIONS This chapter reviews the mole concept, balancing chemical equations, and stoichiometry. The topics covered in this chapter are: Atomic mass and average
More informationThe Mole Concept. A. Atomic Masses and Avogadro s Hypothesis
The Mole Concept A. Atomic Masses and Avogadro s Hypothesis 1. We have learned that compounds are made up of two or more different elements and that elements are composed of atoms. Therefore, compounds
More informationChemical Composition Review Mole Calculations Percent Composition. Copyright Cengage Learning. All rights reserved. 8 1
Chemical Composition Review Mole Calculations Percent Composition Copyright Cengage Learning. All rights reserved. 8 1 QUESTION Suppose you work in a hardware store and a customer wants to purchase 500
More informationChemical bonding is the true difference between compounds and mixtures. Atomic elements:
Chapter 3  Molecules, compounds, and chemical equations Elements and compounds Chemical bonding is the true difference between compounds and mixtures Atomic elements: Ionic bond: attraction of oppositely
More informationTHE MOLE / COUNTING IN CHEMISTRY
1 THE MOLE / COUNTING IN CHEMISTRY ***A mole is 6.0 x 10 items.*** 1 mole = 6.0 x 10 items 1 mole = 60, 00, 000, 000, 000, 000, 000, 000 items Analogy #1 1 dozen = 1 items 18 eggs = 1.5 dz.  to convert
More informationName Block THE MOLE. Who s Counting Lab. Mole Notes. Mole Calculations. Mixed Mole Conversions. % Comp, Emp, and Molecular Calcuations
Name Block THE MOLE Who s Counting Lab Mole Notes Mole Calculations Mixed Mole Conversions % Comp, Emp, and Molecular Calcuations Mole Notes, Part 1 1. The Mole is just a long word for changing units
More informationThe Mole Notes. There are many ways to or measure things. In Chemistry we also have special ways to count and measure things, one of which is the.
The Mole Notes I. Introduction There are many ways to or measure things. In Chemistry we also have special ways to count and measure things, one of which is the. A. The Mole (mol) Recall that atoms of
More informationUnit 5 Chemical Quantities & The Mole
Unit 5 Chemical Quantities & The Mole Molar mass is the mass of one mole of a substance. Molar Mass Other names for molar mass include *formula mass *gram formula mass *molecular weight Molar Mass One
More informationChapter 3 Chemical Reactions and Reaction Stoichiometry. 許富銀 ( Hsu FuYin)
Chapter 3 Chemical Reactions and Reaction Stoichiometry 許富銀 ( Hsu FuYin) 1 Stoichiometry The study of the numerical relationship between chemical quantities in a chemical reaction is called stoichiometry.
More informationChemistry Final Exam Review
Name: Date: Block: Chemistry Final Exam Review 20122013 Unit 1: Measurement, Numbers, Scientific Notation, Conversions, Dimensional Analysis 1. Write 0.000008732 in scientific notation 8.732x106 2. Write
More informationName Date Class CHEMICAL QUANTITIES. SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296)
Name Date Class 10 CHEMICAL QUANTITIES SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296) This section defines the mole and explains how the mole is used to measure matter. It also teaches
More informationTOPIC 7. CHEMICAL CALCULATIONS I  atomic and formula weights.
TOPIC 7. CHEMICAL CALCULATIONS I  atomic and formula weights. Atomic structure revisited. In Topic 2, atoms were described as ranging from the simplest atom, H, containing a single proton and usually
More informationFormula Stoichiometry. Text pages
Formula Stoichiometry Text pages 237250 Formula Mass Review Write a chemical formula for the compound. H 2 CO 3 Look up the average atomic mass for each of the elements. H = 1.008 C= 12.01 O = 16.00 Multiply
More informationCHAPTER 7. Empirical Formulas
CHAPTER 7 Empirical Formulas Suppose you analyze an unknown compound that is a white powder and find that it is composed of 36.5% sodium, 38.1% oxygen, and 25.4% sulfur. You can use those percentages to
More informationCHAPTER 3 Calculations with Chemical Formulas and Equations. atoms in a FORMULA UNIT
CHAPTER 3 Calculations with Chemical Formulas and Equations MOLECULAR WEIGHT (M. W.) Sum of the Atomic Weights of all atoms in a MOLECULE of a substance. FORMULA WEIGHT (F. W.) Sum of the atomic Weights
More informationPercent Composition  Formulas
Percent Composition  Formulas This program demonstrates how to find percentage composition as well as empirical and molecular formulas from that data. Please read each section carefully. You might wish
More informationSimple vs. True Calculating Empirical and Molecular Formulas
17 Calculating Empirical and Molecular Formulas OBJECTIVE Students will learn to calculate empirical and molecular formulas and practice applying logical problemsolving skills. LEVEL Chemistry NATIONAL
More informationIntroduction to Chemistry
1 Copyright ç 1996 Richard Hochstim. All rights reserved. Terms of use. Introduction to Chemistry In Chemistry the word weight is commonly used in place of the more proper term mass. 1.1 Atoms, Ions, and
More informationChapter 5. Quantities in Chemistry
Chapter 5 Quantities in Chemistry REMEMBER: You are required to use dimensional analysis whenever possible, which is almost all of the time in chemistry! If you choose not to use dimensional analysis,
More informationName Date Class CHEMICAL QUANTITIES. SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296)
10 CHEMICAL QUANTITIES SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296) This section defines the mole and explains how the mole is used to measure matter. It also teaches you how to calculate
More informationChemical Calculations: Formula Masses, Moles, and Chemical Equations
Chemical Calculations: Formula Masses, Moles, and Chemical Equations Atomic Mass & Formula Mass Recall from Chapter Three that the average mass of an atom of a given element can be found on the periodic
More informationUnit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test
Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test NAME Section 7.1 The Mole: A Measurement of Matter A. What is a mole? 1. Chemistry is a quantitative science. What does this term mean?
More informationAtomic Masses. Chapter 3. Stoichiometry. Chemical Stoichiometry. Mass and Moles of a Substance. Average Atomic Mass
Atomic Masses Chapter 3 Stoichiometry 1 atomic mass unit (amu) = 1/12 of the mass of a 12 C atom so one 12 C atom has a mass of 12 amu (exact number). From mass spectrometry: 13 C/ 12 C = 1.0836129 amu
More informationNotes: Formula Mass and Percent Composition
Notes: Formula Mass and Percent Composition Formula mass  the mass of one mole of a compound, atom or ion. also called: gram formula mass, molecular mass, gram molecular mass, formula weight, gram formula
More informationChapter 4. The Mole Concept
Chapter 4. The Mole Concept Introduction If you were to take one volume (Eg. 1cm 3 ) of every element, weigh them and rank them according to their weights you would discover that they followed the periodic
More informationHow are molecular formulas different from empirical formulas? Can they ever be the same for a particular substance?
Chapter 3 Reading Guide Tro 3 rd edition Section 3.1, Do the parts add up to the whole? Water is a compound made up of two different elements. Does water have similar properties to H 2 and O 2? Do compounds
More informationCHEM 100 Principles Of Chemistry. Chapter 5  How Chemists Measure Atoms & Molecules
CHEM 100 Principles Of Chemistry Chapter 5  How Chemists Measure Atoms & Molecules 5.1 Weighing Objects to Count Objects When coin parking meters are emptied, the coins are not counted but weighed By
More information10.3 Percent Composition and Chemical Formulas. Chapter 10 Chemical Quantities Percent Composition and Chemical Formulas
Chapter 10 Chemical Quantities 101 The Mole: A Measurement of Matter 102 MoleMass and MoleVolume Relationships 103 Percent Composition and Chemical Formulas 1 CHEMISTRY & YOU What does the percent composition
More information= 16.00 amu. = 39.10 amu
Using Chemical Formulas Objective 1: Calculate the formula mass or molar mass of any given compound. The Formula Mass of any molecule, formula unit, or ion is the sum of the average atomic masses of all
More informationThe Mole. Chapter 2. Solutions for Practice Problems
Chapter 2 The Mole Note to teacher: You will notice that there are two different formats for the Sample Problems in the student textbook. Where appropriate, the Sample Problem contains the full set of
More informationCalculation of Molar Masses. Molar Mass. Solutions. Solutions
Molar Mass Molar mass = Mass in grams of one mole of any element, numerically equal to its atomic weight Molar mass of molecules can be determined from the chemical formula and molar masses of elements
More informationTUTORIAL 51 HELP. Mass of sodium = 23.0 g/mol x 3 mol = 69.0 g of sodium. Percent mass of sodium = 69.0 g x 100% = 42.
TUTORIAL 51 HELP ANSWER TO QUESTION 1 ON TUTORIAL 51: Question 1. Find the percent composition by mass of sodium phosphate, Na 3 PO 4. Step 1: Find the molar mass of Na 3 PO 4 (The mass of one mole of
More informationChapter 2: You must understand chemistry to understand life
Chapter 2: You must understand chemistry to understand life 1. Describe the difference between the terms element and atom. What are chemical symbols, and what is the periodic table? 2. Draw a model of
More informationCHEMISTRY. (i) It failed to explain how atoms of different elements differ from each other.
CHEMISTRY MOLE CONCEPT DALTON S ATOMIC THEORY By observing the laws of chemical combination, John Dalton proposed an atomic theory of matter. The main points of Dalton s atomic theory are as follows: (i)
More informationAmount of Substance. http://www.avogadro.co.uk/definitions/elemcompmix.htm
Page 1 of 14 Amount of Substance Key terms in this chapter are: Element Compound Mixture Atom Molecule Ion Relative Atomic Mass Avogadro constant Mole Isotope Relative Isotopic Mass Relative Molecular
More informationQuantitative Composition of Compounds. Preparation for College Chemistry Luis Avila Columbia University Department of Chemistry
Quantitative Composition of Compounds Preparation for College Chemistry Luis Avila Columbia University Department of Chemistry Depending upon Bonding type Compounds Molecular (Covalent bonds) Ionic (Coulombic
More informationWe know from the information given that we have an equal mass of each compound, but no real numbers to plug in and find moles. So what can we do?
How do we figure this out? We know that: 1) the number of oxygen atoms can be found by using Avogadro s number, if we know the moles of oxygen atoms; 2) the number of moles of oxygen atoms can be found
More informationMOLES AND MOLE CALCULATIONS
35 MOLES ND MOLE CLCULTIONS INTRODUCTION The purpose of this section is to present some methods for calculating both how much of each reactant is used in a chemical reaction, and how much of each product
More informationChapter 6 Notes. Chemical Composition
Chapter 6 Notes Chemical Composition Section 6.1: Counting By Weighing We can weigh a large number of the objects and find the average mass. Once we know the average mass we can equate that to any number
More informationProblem Solving. Empirical Formulas
Skills Worksheet Problem Solving Empirical Formulas Suppose you analyze an unknown compound that is a white powder and find that it is composed of 36.5% sodium, 38.1% oxygen, and 25.4% sulfur. You can
More informationConcept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects.
Chapter 3. Stoichiometry: MoleMass Relationships in Chemical Reactions Concept 1. The meaning and usefulness of the mole The mole (or mol) represents a certain number of objects. SI def.: the amount of
More informationMass and Moles of a Substance
Chapter Three Calculations with Chemical Formulas and Equations Mass and Moles of a Substance Chemistry requires a method for determining the numbers of molecules in a given mass of a substance. This allows
More informationMore on ions (Chapters 2.1 and )
More on ions (Chapters 2.1 and 3.5 3.7) Ion: an atom or molecule that has a net electrical charge. Examples: Na + (sodium ion), Cl  (chloride), NH 4 + (ammonium). Anion: a negative ion, formed when electrons
More informationIB Chemistry 1 Mole. One atom of C12 has a mass of 12 amu. One mole of C12 has a mass of 12 g. Grams we can use more easily.
The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon12 that were needed to make 12 g of carbon. 1 mole
More informationChapter 2. Atoms and Elements
Chapter 2. Atoms and Elements John Dalton Robert Millikan J.J. Thomson Ernest Rutherford The Components of Matter Elements, Compounds, Mixtures Dalton s Atomic Theory Modern Atomic Theory Atomic and Mass
More informationChapter 3. Chemical Reactions and Reaction Stoichiometry. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT
Lecture Presentation Chapter 3 Chemical Reactions and Reaction James F. Kirby Quinnipiac University Hamden, CT The study of the mass relationships in chemistry Based on the Law of Conservation of Mass
More informationChapter 3: Stoichiometry
Chapter 3: Stoichiometry Goal is to understand and become proficient at working with: 1. Avogadro's Number, molar mass and converting between mass and moles (REVIEW). 2. empirical formulas from analysis.
More informationStoichiometry. What is the atomic mass for carbon? For zinc?
Stoichiometry Atomic Mass (atomic weight) Atoms are so small, it is difficult to discuss how much they weigh in grams We use atomic mass units an atomic mass unit (AMU) is one twelfth the mass of the catbon12
More information2/15/2013. Chapter
Chapter 10 1 10.1 You could measure the amount of sand in a sand sculpture by counting each grain of sand, but it would be much easier to weigh the sand. You ll discover how chemists measure the amount
More informationSimple vs. True. Simple vs. True. Calculating Empirical and Molecular Formulas
Calculating Empirical and Molecular Formulas Formula writing is a key component for success in chemistry. How do scientists really know what the true formula for a compound might be? In this lesson we
More informationRelative Mass and the Mole
Why? Relative Mass and the Mole How can atoms be counted using a balance? Consider the following equation for a chemical reaction: 2H 2 + O 2 2H 2 O This can be interpreted as two molecules of hydrogen
More informationSolution. Practice Exercise. Concept Exercise
Example Exercise 9.1 Atomic Mass and Avogadro s Number Refer to the atomic masses in the periodic table inside the front cover of this textbook. State the mass of Avogadro s number of atoms for each of
More informationChemical calculations
Chemical calculations Stoichiometry refers to the quantities of material which react according to a balanced chemical equation. Compounds are formed when atoms combine in fixed proportions. E.g. 2Mg +
More informationCONSERVATION OF MASS During a chemical reaction, matter is neither created nor destroyed.  i. e. the number of atoms of each element remains constant
1 CHEMICAL REACTINS Example: Hydrogen + xygen Water H + H + +  Note there is not enough hydrogen to react with oxygen  It is necessary to balance equation. reactants products + H + H (balanced equation)
More informationThe Mole IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES
The Mole S 6.02 X 10 23 IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES Relative Masses To understand relative scales, let s s ignore electrons and compare atoms by total number of nuclear particles. Hydrogen,
More information