THE MOLE / COUNTING IN CHEMISTRY

Size: px
Start display at page:

Download "THE MOLE / COUNTING IN CHEMISTRY"

Transcription

1 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 from eggs from dozen, we need to multiply by conversion factor 1dz 18eggs = 18eggs = 15. dz 1 eggs Example: How many eggs in. dozen? 1 eggs. dz =. dz = 8eggs 1dz Example: How many dozen is 18 gears? 1dz 18gears = 18gears = gears dz gears Analogy # 1 gross = 144 items Conversion factors are 1gross 144 items and 144 items gross Example: How many gross is 95 pencils? Example: How many apples is 0.47 gross? 1 mole = 6.0 x 10 items (usually ions, atoms or molecules) x 10 is called Avogadro s number and is abbreviated N A. 6.0 x 10 molecules = 1 mole molecule x 10 molecules = mole molecule

2 Example: How many moles of atoms is 7.4 x 10 1 atoms? - use conversion factor 6. 0 x10 items or 6. 0 x10 items mol 1 1 e 7. 4x10 atoms = 7. 4x10 atoms 6. 0 x10 atoms = mol atoms Example: How many moles of ions is.5 x 10 5 ions? Example: How many molecules are in 8. mol of molecules? ATOMIC MASS AND MOLAR MASS How much mass does a hydrogen atom have? 1 p + = m(h) 1.00 amu What is an amu? 1 amu = 1.66 x 10-4 g BY DEFINITION Relationship between atomic mass and molar mass - atomic mass mass of one atom - molar mass mass of a mole of atoms How much mass does a helium atom have? p + + n amu x10 g 400. amu = 664. x10 amu How much mass does a mole of helium atoms have? 4 g x10 atoms 6.64 x10 g 4.00 g = = 4.00g mol atom mol The fact that 1 He atom has 4.00 amu of mass and 1 mole of He atoms has 4.00 g of mass is not a coincidence. Definition of amu is made to ensure this coincidence. The value of 4.00 g/mol is call the molar mass of He.

3 Molar mass of the elements are found on the periodic table. Why aren t molar masses on periodic table integers? 1.) Molar masses are an average of isotopes. - most important reason.) Nuclear energy has mass..) Mass of electrons is very small, but not zero. Converting between mass and moles - a molar mass is a conversion factor! Example: How many moles of atoms are in 96. grams of carbon? Example: How much mass in grams does moles of uranium have? FORMULA MOLAR MASS a.k.a. molecular mass, molecular weight, formula weight, etc Formula Mass (Weight) sum of atomic masses in chemical formula Calculating Formula Mass Example: What is the molar mass of ethylene, C H 4? C: x g/mol = 4.00 g/mol 4 H: 4 x g/mol = g/mol g/mol M(C H 4 ) = g/mol Ethylene is used to ripen fresh fruit. It is also used to make milk jugs. Example: What is the molar mass of Ba(NO )? 1 Ba: 1 x 17. g/mol = 17. g/mol N: x g/mol = g/mol 6 O: 6 x g/mol = g/mol 61.4 g/mol M(Ba(NO ) ) = 61.4 g/mol Barium nitrate is used to color fireworks green.

4 4 Converting between mass and moles Example: How many moles are in 58 g of Ba(NO ) First calculate molar mass. 17. g/mol x g/mol 4 x g/mol 61.4 g/mol 58g = 58g =.06 mol 61.4g Example: How many grams is mol of NaCl? M(NaCl) = g/mol g/mol = g/mol 58.44g mol = mol = 8.59g NaCl Road salt is mined under the city of Detroit. SCHEME: Converting mass to moles to number Mass (g) M Molar Mass Moles (mol) NA Avogadro s Number Number (atoms or molecules) Example: How much mass in grams does 1.8 x 10 molecules of CO have? Example: How many F atoms are in 1.19 g of CaF?

5 5 MASS COMPOSITION OF A COMPOUND - Mass composition tells us percentage of mass for each element in compound. - Mass of molecule equals the sum of the masses of the atoms. - Given a chemical formula, one is able to find the percent mass of each element. Strategy to find percent mass of compound 1. Assume 1 mole of substance. Calculate the total mass of one mole of molecules, i. e., find the molar mass of the compound.. Calculate the mass of a single element by multiplying number of atoms by atomic weight 4. Divide the mass of single element by total mass and multiply by 100% to get percent mass. 5. Repeat for all elements. 6. Adding all percentages should equal 100%. Example: What the mass percentages of the elements in C H 6? 1. Assume 1 mol. M(C H 6 ) = x g/mol + 6 x g/mol = g/mol g/mol = g/mol g For % C. x M(C) = x g/mol = g/mol g. 4. % C 6 045g.. g 100% = % For % H. 6 x M(H) = 6 x g/mol = g/mol g. 4. % H g.. g 100% = % As a check % % = % C H 6 is propylene which is used to make polypropylene. Polypropylene is used to make wash bottles, plastic sheet protectors, long underwear, rope and Tupperware.

6 6 EMPIRICAL FORMULAS - chemical formula with lowest possible ratio of atoms Molecular Formula Empirical Formula C H 6 CH P 4 O 10 P O 5 SnCl SnCl C 6 H 1 O 6 CH O Calculating Empirical Formulas from Mass Percentages Given: Percent Mass Composition Find: Empirical Formula Strategy: 1) Assume 100 g of matter. ) Multiply 100 g by mass percent to find amount of each element. ) Convert mass of each element to moles using molar mass. 4) Find whole number ratios by dividing each number of moles by lowest number of moles. 5) Use these ratios to find empirical formula. Example: Find the empirical formula for a compound with the following mass percentages: 69.6 % O 0.4 % N 1 Assume 100 g m(o) = g x = 69.6 g m(n) = g x 0.04 = 0.4 g O: 69. 6g g = 45. mol O N: 0. 4g g = 17. mol N 4 mol 4.5mol mol = =.00 = mol.17 mol O O O N N N 5 Empirical Formula is NO Nitrogen dioxide is a component of automotive exhaust.

7 7 Example: Find the empirical formula for a compound with the following mass percentages: 4.6 % H 40.9 % C 54.5 % O Empirical Formula is H 4 C O H 4 C O is the empirical formula for ascorbic acid, H 8 C 6 O 6, the chemical name for vitamin C.

8 8 THEORETICAL STOICHIOMETRY - coefficients of balanced equations relate moles of reactants to moles of products - Comparisons in chemistry must be done by comparing numbers of molecules to each other, i. e., comparing number of moles of each substance. Example: N (g) + H (g) NH (g) mole of N is stoichiometrically equivalent to moles of NH. - in other words, for every 1 mole of N reacted, moles of NH are produced. - N mol NH - equivalence is only true for specific chemical reaction - equivalence can be considered a conversion factor N N mol NH mol NH or mol NH N - other equivalences are N mol H mol H mol NH Example: a) What are all of the stoichiometric equivalences for the reaction C H (g) + 5 O (g) 4 CO (g) + H O (g)? molch 5molO C H molco CH H O 5molO 4molCO 5molO mol H O mol CO H O b) How many moles of carbon dioxide are formed when 5 moles of acetylene (C H ) is combusted? 5mol CH molco = 10mol CH c) How many moles of oxygen are needed to fully burn 9.8 moles of acetylene (C H )? CO Acetylene is a welder s fuel.

9 9 Example: For the reaction Pb(NO ) 4 (aq) + 4 KCl (aq) PbCl 4 (s) + 4 KNO (aq), How many moles of KCl are needed to form 15.6 moles of PbCl 4? PRACTICAL STOICHIOMETRY - can t measure moles directly in the real world. - must measure amount of substance with grams. ***Cannot compare substances stoichiometrically by mass, must convert to moles.*** SCHEME: Mass of reactant (g) Mass of product (g) M Molar Mass Moles of reactant (mol) Balanced Equation Moles of product (mol) M Molar Mass Example: For the reaction, NH (g) + (g) NH 4 Cl (s), a) how much NH is needed to react with 9. g of? 1) First convert grams of reactant to moles of reactant 9. g = 5. mol 6. 5g ) Compare moles of one reactant to other reactant. NH 5. mol = 5. mol ) Convert moles of other reactant to grams g NH 5. molnh = 4. 0g mol NH NH NH

10 b) How much ammonium chloride is produced when 9. g of is fully reacted? - Note with factor-label method, we can do problems all on one line. 9. g 55. g NH 4Cl NH 4Cl = 15g 65. g mol NH Cl The reaction of ammonia with hydrogen chloride gas is used to a smokescreen. 4 NH Cl Example: For the reaction 4BaCO (s) + Y (CO ) (s) + 6 CuCO (s) YBa Cu O 7 (s) + 1 CO (g) + O (g) a) Calculate how many grams of CuCO is needed to fully react with g of BaCO, 4 10 b) Calculate how many grams of YBa Cu O 7 is formed from g of BaCO fully reacting. Yttrium barium copper oxide (YBCO) is a superconducting ceramic. It is superconducting below a temperature of 95 K. Example: For the reaction SiO (s) + 6 HF (aq) H SiF 6 (aq) + H O (aq), a) Calculate how many grams of HF is needed to fully react with g of silicon dioxide, b) How much H SiF 6 is made when 1.4 g of HF fully reacts? Hydrofluoric acid, HF(aq), is used to frost glass, SiO.

11 LIMITING REAGENTS - Often starting materials are not available in proper stoichiometric proportions. - Given unbalanced amounts of reactants, we would like to know how much product can be produced. Analogy: Bicycle Factory The equation to make a bicycle is wheels + 1 frame + 1 handlebar 1 bicycle 11 If the parts inventory is as follows: 40 wheels 150 frames we ask ourselves - What reactant limits production? - How much product can be produced? 15 handlebars, 40 wheel frame + 15 handlebar?? bicycle 1bicycle 40wheels = 10bicycles wheels 1bicycle 150frames = 150bicycles 1frame 1bicycle 15handlebars = 15bicycles 1handlebars Limiting reactant: wheels Production: 10 bicycles In a limiting reactant problem, amounts of two (or more) reactant are given. Calculate how much product is produced by each. The reactant that yields the lowest amount of product is the limiting reactant. ***In limiting reagent problems, we need to compare moles to moles*** Example: For the reaction SO (g) + O (g) + H O (l) H SO 4 (aq), if 5.6 mol of SO, 4.8 mol of O and 6.0 mol of H O are reacted together, how many moles of H SO 4 are produced? HSO4 For the SO : 56. molso = 56. mol HSO4 SO molhso4 For the O : 48. molo = 96. mol For the H O: O 6.0 mol = HSO4 HSO4 HO 6.0 molh SO4 HO SO is limiting reactant and therefore 5.6 moles of H SO 4 is produced. Sulfur dioxide is a pollutant from burning coal that is a contributor to acid rain. Sulfur dioxide is removed from air with calcium oxide. SO (g) + CaO (s) CaSO (s)

12 1 Example: For the reaction Zn (s) + CuCl (aq) ZnCl (aq) + Cu (s), what mass of copper metal is produced from the reaction of.00 g of Zn and.00 g of CuCl? Find limiting reactant by comparing moles to moles Must convert mass to moles using molar mass as conversion factor. Thus CuCl is the limiting reactant and the amount of copper produced is REACTION YIELDS - We have been calculating theoretical yields by assuming that the reactions proceed perfectly. - An actual chemical process is rarely perfect; therefore, the actual yield is always less than the theoretical yield. - We compare the actual yield to the theoretical yield by calculating percent yield. Definition of percent yield %yield actual yield = 100% theoretical yield Example: For the reaction Cr O (s) + Al (s) Cr (s) + Al O (s) 18.7 g of Chromium (III) oxide reacts to form 10.8 g of chromium metal. What the percent yield of this process? Theoretical yield of chromium metal is Thus the percent yield is 108. gcr % yield = 100% = 84. 4% 1. 8g Cr

13 1 BOND ENTHALPIES When two atoms bond together, the chemical energy of the system decreases. Consider an energy level diagram of before bonding and after bonding. H H H H before The energy of the bonded system is lower than the unbonded system. The energy released when two unbonded atoms become bonded is called the bond enthalpy. Aside: Enthalpy is another word for heat. The bond enthalpy increases as atoms are more strongly bonded together. As the strength of the bond increases, the distance between the atoms decreases. Bond enthalpies are an experimentally found quantity; i. e., we can t predict bond enthalpies from periodic table. Bond Enthalpies and Chemical Changes after **All chemical changes involve the breaking and creation of bonds.** If we can understand what bonds are breaking and what bonds are forming, then we can use bond enthalpies to estimate the energy (technically, enthalpy) change of the reaction. To break a bond, we input (add) the bond enthalpy. When a bond is formed, the bond enthalpy is released (subtracted).

14 Example: Given the table of bond enthalpies below, calculate the energy change, when two molecules of hydrogen and one molecule of oxygen change into two molecules of water. 14 H H H H + O O O H H O H H TABLE OF BOND ENTHALPIES Bond E (kj/mol) Bond E (kj/mol) C H 41 H H 46 C C 48 N N 16 C O 58 N = N 418 C = C 614 N N 941 C C 89 O H 46 C = O 107 O = O 495 Breaking two H H bonds means inputting x 46 kj/mol. Breaking one O = O bond means inputting 495 kj/mol. Forming four O H bonds means releasing 4 x 46 kj/mol. Overall the energy change is

CONSERVATION OF MASS During a chemical reaction, matter is neither created nor destroyed. - i. e. the number of atoms of each element remains constant

CONSERVATION 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 information

Chapter 3. Stoichiometry: Ratios of Combination. Insert picture from First page of chapter. Copyright McGraw-Hill 2009 1

Chapter 3. Stoichiometry: Ratios of Combination. Insert picture from First page of chapter. Copyright McGraw-Hill 2009 1 Chapter 3 Insert picture from First page of chapter Stoichiometry: Ratios of Combination Copyright McGraw-Hill 2009 1 3.1 Molecular and Formula Masses Molecular mass - (molecular weight) The mass in amu

More information

Formulas, Equations, and Moles. + "reacts with" "to produce" Equations must be balanced. Equal amounts of each element on each side of the equation.

Formulas, 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 information

Chapter 3: Stoichiometry

Chapter 3: Stoichiometry Chapter 3: Stoichiometry Key Skills: Balance chemical equations Predict the products of simple combination, decomposition, and combustion reactions. Calculate formula weights Convert grams to moles and

More information

The Mole Concept. The Mole. Masses of molecules

The Mole Concept. The Mole. Masses of molecules The Mole Concept Ron Robertson r2 c:\files\courses\1110-20\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 information

Chemical Calculations: The Mole Concept and Chemical Formulas. AW Atomic weight (mass of the atom of an element) was determined by relative weights.

Chemical 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 information

Part One: Mass and Moles of Substance. Molecular Mass = sum of the Atomic Masses in a molecule

Part 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 information

Calculating Atoms, Ions, or Molecules Using Moles

Calculating 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 information

How 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. 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 information

Chemical Reactions. Chemical Equations. Mole as Conversion Factor: To convert between number of particles and an equivalent number of moles:

Chemical 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 book-keeping Chemical Equations Chemical equations: Describe proportions

More information

AP Chemistry. Unit #3. Chapter 3 Zumdahl

AP Chemistry. Unit #3. Chapter 3 Zumdahl AP Chemistry Unit #3 Chapter 3 Zumdahl Stoichiometry C6H12O6 + 6 O2 6 CO2 + 6 H2O Students should be able to: Calculate the atomic weight (average atomic mass) of an element from the relative abundances

More information

Chapter 3! Stoichiometry: Calculations with Chemical Formulas and Equations. Stoichiometry

Chapter 3! Stoichiometry: Calculations with Chemical Formulas and Equations. Stoichiometry Chapter 3! : Calculations with Chemical Formulas and Equations Anatomy of a Chemical Equation CH 4 (g) + 2O 2 (g) CO 2 (g) + 2 H 2 O (g) Anatomy of a Chemical Equation CH 4 (g) + 2 O 2 (g) CO 2 (g) + 2

More information

Mass and Moles of a Substance

Mass 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 information

1. How many hydrogen atoms are in 1.00 g of hydrogen?

1. 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 10-24 g B. We need a conversion to the macroscopic world. 1. How many hydrogen atoms are in 1.00 g of hydrogen?

More information

Chapter 3 Chemical Reactions and Reaction Stoichiometry. 許富銀 ( Hsu Fu-Yin)

Chapter 3 Chemical Reactions and Reaction Stoichiometry. 許富銀 ( Hsu Fu-Yin) Chapter 3 Chemical Reactions and Reaction Stoichiometry 許富銀 ( Hsu Fu-Yin) 1 Stoichiometry The study of the numerical relationship between chemical quantities in a chemical reaction is called stoichiometry.

More information

The mass of the formula unit is called the formula mass Formula masses are calculated the same way as molecular masses

The 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 information

Grams A Moles A Moles B Grams B

Grams A Moles A Moles B Grams B STOICHIOMETRY--The quantitative relationship among the reactants and products in a balanced chemical equation. The stoichiometric coefficients do not affect sig figs. Stoichiometric calculations can be

More information

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

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

More information

MOLE CONVERSION PROBLEMS. 2. How many moles are present in 34 grams of Cu(OH) 2? [0.35 moles]

MOLE CONVERSION PROBLEMS. 2. How many moles are present in 34 grams of Cu(OH) 2? [0.35 moles] MOLE CONVERSION PROBLEMS 1. What is the molar mass of MgO? [40.31 g/mol] 2. How many moles are present in 34 grams of Cu(OH) 2? [0.35 moles] 3. How many moles are present in 2.5 x 10 23 molecules of CH

More information

Chapter 3. Chemical Reactions and Reaction Stoichiometry. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT

Chapter 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 information

Chapter 3 Calculation with Chemical Formulas and Equations

Chapter 3 Calculation with Chemical Formulas and Equations Chapter 3 Calculation with Chemical Formulas and Equations Practical Applications of Chemistry Determining chemical formula of a substance Predicting the amount of substances consumed during a reaction

More information

Moles. Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations

Moles. Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations Moles Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations Micro World atoms & molecules Macro World grams Atomic mass is the mass of an

More information

Chapter 1 The Atomic Nature of Matter

Chapter 1 The Atomic Nature of Matter Chapter 1 The Atomic Nature of Matter 6. Substances that cannot be decomposed into two or more simpler substances by chemical means are called a. pure substances. b. compounds. c. molecules. d. elements.

More information

Chapter 3: Stoichiometry

Chapter 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 information

Unit 10A Stoichiometry Notes

Unit 10A Stoichiometry Notes Unit 10A Stoichiometry Notes Stoichiometry is a big word for a process that chemist s use to calculate amounts in reactions. It makes use of the coefficient ratio set up by balanced reaction equations

More information

Stoichiometry. What is the atomic mass for carbon? For zinc?

Stoichiometry. 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 catbon-12

More information

MASS RELATIONS IN CHEMISTRY; STOICHIOMETRY

MASS 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 information

CHEMISTRY CP Name: KEY Period: UNIT 5: TEST REVIEW SHEET MOLE CONVERSIONS, EMPIRICAL/MOLECULAR FORMULA, STOICHIOMETRY

CHEMISTRY CP Name: KEY Period: UNIT 5: TEST REVIEW SHEET MOLE CONVERSIONS, EMPIRICAL/MOLECULAR FORMULA, STOICHIOMETRY CHEMISTRY CP Name: KEY Period: UNIT 5: TEST REVIEW SHEET MOLE CONVERSIONS, EMPIRICAL/MOLECULAR FORMULA, STOICHIOMETRY MOLES AND MOLE CONVERSIONS 1. Things to Know: a. What is a mole? Avogadro s number

More information

Practice questions for Ch. 3

Practice questions for Ch. 3 Name: Class: Date: ID: A Practice questions for Ch. 3 1. A hypothetical element consists of two isotopes of masses 69.95 amu and 71.95 amu with abundances of 25.7% and 74.3%, respectively. What is the

More information

MOLES AND MOLE CALCULATIONS

MOLES 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 information

SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001

SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, Chemistry 11, McGraw-Hill Ryerson, 2001 SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001 1. A small pin contains 0.0178 mol of iron. How many atoms of iron are in the pin? 2. A sample

More information

Calculations and Chemical Equations. Example: Hydrogen atomic weight = 1.008 amu Carbon atomic weight = 12.001 amu

Calculations and Chemical Equations. Example: Hydrogen atomic weight = 1.008 amu Carbon atomic weight = 12.001 amu Calculations and Chemical Equations Atomic mass: Mass of an atom of an element, expressed in atomic mass units Atomic mass unit (amu): 1.661 x 10-24 g Atomic weight: Average mass of all isotopes of a given

More information

Chemical Reactions. Chemical Arithmetic

Chemical Reactions. Chemical Arithmetic Chemical Reactions Chapter 6 Chemical Arithmetic Balancing Equations The mole Gram - mole conversions Mole - mole relationships in chemical equations Mass relationships in chemical equations Per cent yeilds

More information

Subscripts and Coefficients Give Different Information

Subscripts and Coefficients Give Different Information Chapter 3: Stoichiometry Goal is to understand and become proficient at working with: 1. Chemical equations (Balancing REVIEW) 2. Some simple patterns of reactivity 3. Formula weights (REVIEW) 4. Avogadro's

More information

CHAPTER 3 STOICHIOMETRY OF FORMULAS AND EQUATIONS

CHAPTER 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 information

MASS RELATIONSHIPS IN CHEMICAL REACTIONS

MASS RELATIONSHIPS IN CHEMICAL REACTIONS MASS RELATIONSHIPS IN CHEMICAL REACTIONS 1. The mole, Avogadro s number and molar mass of an element. Molecular mass (molecular weight) 3. Percent composition of compounds 4. Empirical and Molecular formulas

More information

0.786 mol carbon dioxide to grams g lithium carbonate to mol

0.786 mol carbon dioxide to grams g lithium carbonate to mol 1 2 Convert: 2.54 x 10 22 atoms of Cr to mol 4.32 mol NaCl to grams 0.786 mol carbon dioxide to grams 2.67 g lithium carbonate to mol 1.000 atom of C 12 to grams 3 Convert: 2.54 x 10 22 atoms of Cr to

More information

Chapter 9. Slide 1. Slide 2. Slide 3. Chemical Quantities. Table of Contents

Chapter 9. Slide 1. Slide 2. Slide 3. Chemical Quantities. Table of Contents 1 Chapter 9 Chemical Quantities 2 Chapter 9 Table of Contents 9.1 Information Given by Chemical Equations 9.2 9.3 Copyright Cengage Learning. All rights reserved 2 3 Section 9.1 Information Given by Chemical

More information

Study Guide For Chapter 7

Study 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 information

Sample Exercise 3.1 Interpreting and Balancing Chemical Equations

Sample Exercise 3.1 Interpreting and Balancing Chemical Equations Sample Exercise 3.1 Interpreting and Balancing Chemical Equations The following diagram represents a chemical reaction in which the red spheres are oxygen atoms and the blue spheres are nitrogen atoms.

More information

Outline. 6.1 The Mole and Avogadro s Number. 6.2 Gram Mole Conversions. 6.3 Mole Relationships and Chemical Equations

Outline. 6.1 The Mole and Avogadro s Number. 6.2 Gram Mole Conversions. 6.3 Mole Relationships and Chemical Equations Outline 6.1 The Mole and Avogadro s Number 6.2 Gram Mole Conversions 6.3 Mole Relationships and Chemical Equations 6.4 Mass Relationships and Chemical Equations 6.5 Limiting Reagent and Percent Yield Goals

More information

CP Chapter 12 Stoichiometry

CP Chapter 12 Stoichiometry CP Chapter 12 Stoichiometry What is Stoichiometry? ( STOY-KEE-AHM-EH-TREE) Stoichiometry is the part of chemistry that studies amounts of reactants and products that are involved in reactions. Chemists

More information

Formulae, stoichiometry and the mole concept

Formulae, stoichiometry and the mole concept 3 Formulae, stoichiometry and the mole concept Content 3.1 Symbols, Formulae and Chemical equations 3.2 Concept of Relative Mass 3.3 Mole Concept and Stoichiometry Learning Outcomes Candidates should be

More information

Chapter 6 Chemical Calculations

Chapter 6 Chemical Calculations Chapter 6 Chemical Calculations 1 Submicroscopic Macroscopic 2 Chapter Outline 1. Formula Masses (Ch 6.1) 2. Percent Composition (supplemental material) 3. The Mole & Avogadro s Number (Ch 6.2) 4. Molar

More information

IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily.

IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 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 carbon-12 that were needed to make 12 g of carbon. 1 mole

More information

Stoichiometry Dr. M. E. Bridge

Stoichiometry Dr. M. E. Bridge Preliminary Chemistry Course Stoichiometry Dr. M. E. Bridge What is stoichiometry? The meaning of the word: The word stoichiometry comes from two Greek words: (meaning element ) and (meaning measure )

More information

Stoichiometry (greek): Stoicheion element, metry to measure

Stoichiometry (greek): Stoicheion element, metry to measure Stoichiometry Stoichiometry (greek): Stoicheion element, metry to measure Balanced Chemical equation: Skills Tells Ex. formula writing balancing equations substances involved in the chemical rxn relationship

More information

Atomic Masses. Chapter 3. Stoichiometry. Chemical Stoichiometry. Mass and Moles of a Substance. Average Atomic Mass

Atomic 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 information

Chemical Calculations: Formula Masses, Moles, and Chemical Equations

Chemical 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 information

Lecture 5, The Mole. What is a mole?

Lecture 5, The Mole. What is a mole? Lecture 5, The Mole What is a mole? Moles Atomic mass unit and the mole amu definition: 12 C = 12 amu. The atomic mass unit is defined this way. 1 amu = 1.6605 x 10-24 g How many 12 C atoms weigh 12 g?

More information

Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses

Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses B. Calculations of moles C. Calculations of number of atoms from moles/molar masses 1. Avagadro

More information

Chemical Proportions in Compounds

Chemical Proportions in Compounds Chapter 6 Chemical Proportions in Compounds Solutions for Practice Problems Student Textbook page 201 1. Problem A sample of a compound is analyzed and found to contain 0.90 g of calcium and 1.60 g of

More information

CHAPTER 3 MASS RELATIONSHIPS IN CHEMICAL REACTIONS

CHAPTER 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 information

7.1 Stoichiometry and Percent Yield

7.1 Stoichiometry and Percent Yield score /10 pts. Name Class Date 7.1 Stoichiometry and Percent Yield Mole Ratios An example: The combustion of propane is used to heat many rural homes in winter. Balance the equation below for the combustion

More information

Unit 6 The Mole Concept

Unit 6 The Mole Concept Chemistry Form 3 Page 62 Ms. R. Buttigieg Unit 6 The Mole Concept See Chemistry for You Chapter 28 pg. 352-363 See GCSE Chemistry Chapter 5 pg. 70-79 6.1 Relative atomic mass. The relative atomic mass

More information

Chapter 7. Chapter 7. Chemical Formulas Express Composition. Chapter 7 MARCH REVIEW SLIDES LISTEN AND UPDATE MISSING NOTES

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 information

Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations

Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations CHE11 Chapter Chapter Stoichiometry: Calculations with Chemical Formulas and Equations 1. When the following equation is balanced, the coefficients are. NH (g) + O (g) NO (g) + H O (g) (a). 1, 1, 1, 1

More information

Balance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O

Balance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O Balance the following equation: KClO 3 + C 12 H 22 O 11 KCl + CO 2 + H 2 O Ans: 8 KClO 3 + C 12 H 22 O 11 8 KCl + 12 CO 2 + 11 H 2 O 3.2 Chemical Symbols at Different levels Chemical symbols represent

More information

Chemical Equations & Stoichiometry

Chemical Equations & Stoichiometry Chemical Equations & Stoichiometry Chapter Goals Balance equations for simple chemical reactions. Perform stoichiometry calculations using balanced chemical equations. Understand the meaning of the term

More information

PERIODIC TABLE OF ELEMENTS. 4/23/14 Chapter 7: Chemical Reactions 1

PERIODIC TABLE OF ELEMENTS. 4/23/14 Chapter 7: Chemical Reactions 1 PERIODIC TABLE OF ELEMENTS 4/23/14 Chapter 7: Chemical Reactions 1 CHAPTER 7: CHEMICAL REACTIONS 7.1 Describing Reactions 7.2 Types of Reactions 7.3 Energy Changes in Reactions 7.4 Reaction Rates 7.5 Equilibrium

More information

Stoichiometry. Types of Problems. Stoichiometry. Chemistry 1010 Review Tutorial 4/9/2013. Stoichiometry and Lewis Structures

Stoichiometry. Types of Problems. Stoichiometry. Chemistry 1010 Review Tutorial 4/9/2013. Stoichiometry and Lewis Structures Stoichiometry Chemistry 1010 Review Tutorial Stoichiometry and Lewis Structures April 9 th, 2013 Stoichiometry Stoichiometry involves MOLES Elements/compounds can only be compared side by side using moles

More information

4. Magnesium has three natural isotopes with the following masses and natural abundances:

4. Magnesium has three natural isotopes with the following masses and natural abundances: Exercise #1 Atomic Masses 1. The average mass of pennies minted after 1982 is 2.50 g and the average mass of pennies minted before 1982 is 3.00 g. In a sample that contains 90.0% new and 10.0% old pennies,

More information

Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4)

Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C-4.4) Honors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1 1. 2. 3. 4. 5. 6. Question What is a symbolic representation of a chemical reaction? What 3 things (values) is a mole of a chemical

More information

Chemistry Stoichiometry Lesson 8 Lesson Plan David V. Fansler

Chemistry Stoichiometry Lesson 8 Lesson Plan David V. Fansler Chemistry Stoichiometry Lesson 8 Lesson Plan David V. Fansler The Arithmetic of Equations Objectives: Interpret balanced chemical equations in terms of interacting moles, representative particles, masses,

More information

Formulas, Equations and Moles

Formulas, Equations and Moles Chapter 3 Formulas, Equations and Moles Interpreting Chemical Equations You can interpret a balanced chemical equation in many ways. On a microscopic level, two molecules of H 2 react with one molecule

More information

CHEMICAL QUANTITIES. Chapter 10

CHEMICAL 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 information

Chemistry 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. 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 information

Unit 9 Stoichiometry Notes (The Mole Continues)

Unit 9 Stoichiometry Notes (The Mole Continues) Unit 9 Stoichiometry Notes (The Mole Continues) is a big word for a process that chemist s use to calculate amounts in reactions. It makes use of the coefficient ratio set up by balanced reaction equations

More information

STOICHIOMETRY. - the study of the quantitative aspects of chemical

STOICHIOMETRY. - the study of the quantitative aspects of chemical STOICHIOMETRY - the study of the quantitative aspects of chemical GENERAL PLAN FOR STOICHIOMETRY Mass reactant Mass product Moles reactant Stoichiometric factor Moles product STOICHIOMETRY It rests on

More information

Mole Notes.notebook. October 29, 2014

Mole Notes.notebook. October 29, 2014 1 2 How do chemists count atoms/formula units/molecules? How do we go from the atomic scale to the scale of everyday measurements (macroscopic scale)? The gateway is the mole! But before we get to the

More information

Chemical Equations and Calculations

Chemical Equations and Calculations Chemical Equations and Calculations A chemical equation is a shorthand way of indicating what is going on in a chemical reaction. We could do it the long way Two molecules of Hydrogen gas react with one

More information

Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry

Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Why? Chemists are concerned with mass relationships in chemical reactions, usually run on a macroscopic scale (grams, kilograms, etc.). To deal with

More information

Chemistry Final Study Guide

Chemistry Final Study Guide Name: Class: Date: Chemistry Final Study Guide Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The electrons involved in the formation of a covalent bond

More information

CHEMISTRY. (i) It failed to explain how atoms of different elements differ from each other.

CHEMISTRY. (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 information

Concept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects.

Concept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects. Chapter 3. Stoichiometry: Mole-Mass 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 information

Chapter 10 Chemical Quantities

Chapter 10 Chemical Quantities Chapter 10 Chemical Quantities 101 The Mole: A Measurement 102 Mole-Mass and Mole-Volume Relationships 103 Percent Composition and Chemical Formulas 1 Copyright Pearson Education, Inc, or its affiliates

More information

CHAPTER 3 Calculations with Chemical Formulas and Equations. atoms in a FORMULA UNIT

CHAPTER 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 information

INTRODUCTORY CHEMISTRY Concepts and Critical Thinking

INTRODUCTORY 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 information

Chemical Quantities: The Mole Chapter 7 Assignment & Problem Set

Chemical Quantities: The Mole Chapter 7 Assignment & Problem Set Chemical Quantities: The Mole Name Warm-Ups (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 information

If you remember, we left off this part of the story with defining the mass of one 12

If you remember, we left off this part of the story with defining the mass of one 12 Chapter 11 Chemical Calculations For the past several weeks we have been working on our qualitative understanding of first atoms, then molecules, and finally chemical reactions. In this chapter we enter

More information

stoichiometry = the numerical relationships between chemical amounts in a reaction.

stoichiometry = the numerical relationships between chemical amounts in a reaction. 1 REACTIONS AND YIELD ANSWERS stoichiometry = the numerical relationships between chemical amounts in a reaction. 2C 8 H 18 (l) + 25O 2 16CO 2 (g) + 18H 2 O(g) From the equation, 16 moles of CO 2 (a greenhouse

More information

2 Stoichiometry: Chemical Arithmetic Formula Conventions (1 of 24) 2 Stoichiometry: Chemical Arithmetic Stoichiometry Terms (2 of 24)

2 Stoichiometry: Chemical Arithmetic Formula Conventions (1 of 24) 2 Stoichiometry: Chemical Arithmetic Stoichiometry Terms (2 of 24) Formula Conventions (1 of 24) Superscripts used to show the charges on ions Mg 2+ the 2 means a 2+ charge (lost 2 electrons) Subscripts used to show numbers of atoms in a formula unit H 2 SO 4 two H s,

More information

1. P 2 O 5 2. P 5 O 2 3. P 10 O 4 4. P 4 O 10

1. P 2 O 5 2. P 5 O 2 3. P 10 O 4 4. P 4 O 10 Teacher: Mr. gerraputa Print Close Name: 1. A chemical formula is an expression used to represent 1. mixtures, only 3. compounds, only 2. elements, only 4. compounds and elements 2. What is the total number

More information

PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points)

PART I: MULTIPLE CHOICE (30 multiple choice questions. Each multiple choice question is worth 2 points) CHEMISTRY 123-07 Midterm #1 Answer key October 14, 2010 Statistics: Average: 74 p (74%); Highest: 97 p (95%); Lowest: 33 p (33%) Number of students performing at or above average: 67 (57%) Number of students

More information

21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11

21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11 21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11 1. Consider the equation: 2Ca(s) + O 2 (g) 2CaO(s) Which of the following statements are correct? (1) Calcium and oxygen are reactants.

More information

Stoichiometry Chapter 9 Assignment & Problem Set

Stoichiometry Chapter 9 Assignment & Problem Set Stoichiometry Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Stoichiometry 2 Study Guide: Things You Must Know Vocabulary (know the definition

More information

Chapter 3. Stoichiometry of Formulas and Equations

Chapter 3. Stoichiometry of Formulas and Equations Chapter 3 Stoichiometry of Formulas and Equations Chapter 3 Outline: Mole - Mass Relationships in Chemical Systems 3.1 The Mole 3.2 Determining the Formula of an Unknown Compound 3.3 Writing and Balancing

More information

Sample Problem: STOICHIOMETRY and percent yield calculations. How much H 2 O will be formed if 454 g of. decomposes? NH 4 NO 3 N 2 O + 2 H 2 O

Sample Problem: STOICHIOMETRY and percent yield calculations. How much H 2 O will be formed if 454 g of. decomposes? NH 4 NO 3 N 2 O + 2 H 2 O STOICHIOMETRY and percent yield calculations 1 Steps for solving Stoichiometric Problems 2 Step 1 Write the balanced equation for the reaction. Step 2 Identify your known and unknown quantities. Step 3

More information

Chapter 4 Chemical Composition

Chapter 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 information

Chapter 3 Mass Relationships in Chemical Reactions

Chapter 3 Mass Relationships in Chemical Reactions Chapter 3 Mass Relationships in Chemical Reactions Student: 1. An atom of bromine has a mass about four times greater than that of an atom of neon. Which choice makes the correct comparison of the relative

More information

Unit 2: Quantities in Chemistry

Unit 2: Quantities in Chemistry Mass, Moles, & Molar Mass Relative quantities of isotopes in a natural occurring element (%) E.g. Carbon has 2 isotopes C-12 and C-13. Of Carbon s two isotopes, there is 98.9% C-12 and 11.1% C-13. Find

More information

Chemical Proportions in Compounds

Chemical Proportions in Compounds Chapter 3 Chemical Proportions in Compounds 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

More information

EMPIRICAL AND MOLECULAR FORMULA

EMPIRICAL AND MOLECULAR FORMULA EMPIRICAL AND MOLECULAR FORMULA Percent Composition: law of constant composition states that any sample of a pure compound always consists of the same elements combined in the same proportions by mass

More information

Chapter 7 Part II: Chemical Formulas and Equations. Mr. Chumbley Chemistry 1-2

Chapter 7 Part II: Chemical Formulas and Equations. Mr. Chumbley Chemistry 1-2 Chapter 7 Part II: Chemical Formulas and Equations Mr. Chumbley Chemistry 1-2 SECTION 3: USING CHEMICAL FORMULAS Molecules and Formula Unit We have not yet discussed the different ways in which chemical

More information

CP Chemistry Review for Stoichiometry Test

CP Chemistry Review for Stoichiometry Test CP Chemistry Review for Stoichiometry Test Stoichiometry Problems (one given reactant): 1. Make sure you have a balanced chemical equation 2. Convert to moles of the known substance. (Use the periodic

More information

Chem 31 Fall 2002. Chapter 3. Stoichiometry: Calculations with Chemical Formulas and Equations. Writing and Balancing Chemical Equations

Chem 31 Fall 2002. Chapter 3. Stoichiometry: Calculations with Chemical Formulas and Equations. Writing and Balancing Chemical Equations Chem 31 Fall 2002 Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations Writing and Balancing Chemical Equations 1. Write Equation in Words -you cannot write an equation unless you

More information

Chapter 4 Chemical Equations & Stoichiometry

Chapter 4 Chemical Equations & Stoichiometry Chapter 4 Chemical Equations & Stoichiometry Chemical reactions are best described using equations which tells us what compounds we started with (reactants), what we did to them (reaction conditions) and

More information

CHEM 100 Principles Of Chemistry. Chapter 5 - How Chemists Measure Atoms & Molecules

CHEM 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 information

Section 7.1 Describing Reactions (pages )

Section 7.1 Describing Reactions (pages ) Section 7.1 Describing Reactions (pages 192 198) This section discusses the use of chemical equations and how to balance them. It also demonstrates the use of calculations in chemistry. Reading Strategy

More information

The Mole Concept and Atoms

The Mole Concept and Atoms Copyright The McGraw-Hill 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 information