CONSERVATION OF MASS During a chemical reaction, matter is neither created nor destroyed. - i. e. the number of atoms of each element remains constant
|
|
- Gordon McCarthy
- 7 years ago
- Views:
Transcription
1 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) CNSERVATIN F MASS During a chemical reaction, matter is neither created nor destroyed. - i. e. the number of atoms of each element remains constant BALANCING CHEMICAL EQUATINS - ensures # of reactant atoms = # of product atoms CH4 + C + H Cu + S8 CuS Fe3 + C Fe + C Sc3 + H Sc(H)3 CH3NH + C + H + N - Sometimes it is more convenient to balance groups of atoms (polyatomic ions) than individual atoms. AgN3 + CaCl Ca(N3) + AgCl - Balance N3 - ions rather than N and atoms. Ba(Cl4) + NaS4 BaS4 + NaCl4 - Balance Cl4 - and S4 - ions.
2 FRMULA AND MLECULAR MASS Formula Mass (Weight) sum of atomic masses in chemical formula Molecular Mass (Weight) same as formula mass for molecular compounds - technically not defined for ionic compounds Clarification of definitions - often the words mass and weight are used interchangeably even though they are technically not the same thing. - often formula mass and molecular mass are used interchangeably even though they are technically not the same things Calculating Formula Mass Example: C3H6 (cyclopropane) 3 (1.011 amu) + 6 ( amu) = amu Example: Ca(H) (calcium hydroxide) amu + ( amu) + ( amu) = amu THE MLE ***A mole is 6.0 x 10 3 items.*** 1 mole = 6.0 x 10 3 items Analogy 1 dozen = 1 items 18 eggs = 1.5 dz. - to convert from eggs from dozen, we need to multiply by conversion factor Example: How many eggs in 3. dozen? Analogy # 1 gross = 144 items Example: How many gross is 68 pencils?
3 3 1 mole = 6.0 x 10 3 items x 10 3 is called Avogadro s number and is abbreviated NA. 6.0 x 10 3 molecules = 1 molemolecule x 10 3 molecules = molemolecule Example: How many moles of atoms is 7.43 x 10 1 atoms? Example: How many moles of ions is.5 x 10 5 ions? Example: How many molecules are in mol of molecules? MLAR MASS Definition of Molar Mass Mass of 1 mole 1 C is g BY DEFINITIN Recall 1 atom of 1 C is amu *This is not a coincidence* Definition of amu and a mole are made to ensure coincidence 1 amu = 1.66 x 10-7 kg = 1/NA grams 1 molc-1 = g molc-1 = g gC molC molc g mol C 1 ATMIC MLAR MASS 1 C: 1 atom = 1 amu 1 mol = 1 g M( 1 C) = 1 g/mol 4 Mg: 1 atom = 4 amu 1 mol = 4 g M( 4 Mg) = 4 g/mol 56 Fe: 1 atom = 56 amu 1 mol = 56 g M( 56 Fe) = 56 g/mol C 1
4 AVERAGE ATMIC MLAR MASS - Elements often have two or more naturally occurring isotopes - Average atomic molar mass is the average of all atomic molar masses of the naturally occurring isotopes according to each isotope s relative abundance - Except for units, identical to average atomic mass - Note: mass of isotopes not integers because of nuclear forces Example: Neon nuclide abundance mass(g/mol) 0 Ne 90.48% Ne 0.7% Ne 9.5% M(Ne) = (19.99 g/mol) (0.994 g/mol) (1.991 g/mol) = 0.18 g/mol - Note: example is the same as example for average atomic mass Example: How many moles of atoms are in 96.3 grams of carbon? Example: How much mass does moles of uranium have? FRMULA MLAR MASS - add molar masses for all atoms within a chemical formula Example: ethene, CH4 M(CH4) = x g/mol + 4 x g/mol = g/mol Ethene (ethylene) is used to ripen fresh fruit. It is also used to make polyethylene, which is used to make milk jugs. Example: How many moles are in 538 g of Ba(N3) First calculate formula weight g/mol x g/mol 6 x g/mol g/mol 538g 538g 06. mol g Barium nitrate is used to color fireworks green.
5 5 SCHEME: Converting mass to moles to number Mass (g) M Molar mass Moles (mol) NA Avogadro s number Note: Molar mass and Avogadro s number are conversion factors Number (atoms or molecules) Example: How many atoms are in 0.1 g of He? Example: How many F atoms are in g of CaF? EMPIRICAL FRMULA FRM MASS PERCENT ANALYSIS 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. 3) 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.
6 6 Example: Find the empirical formula for a compound with the following mass percentages: % Cl % C.6 % H Cl: g x = g C: g x = g H: g x 0.06 =.6 g 3 H: C: Cl: 4 Empirical Formula is CH3Cl3
7 7 CMBUSTIN ANALYSIS A mass of hydrocarbon is burnt with oxygen to produce C, H and N. From the mass of C, H and N produced and mass of oxygen used, find the empirical formula for the compound. Ultimately, we want to find molar ratios that we ll use to find the empirical formula. 1. Convert mass of C to moles of carbon atoms. - calculation yields moles of carbon in hydrocarbon sample. C (g) + KH (s) KHC3 (s). Convert mass of H to moles of hydrogen atoms. - because there are two moles of hydrogen to one mole of water, multiply result by to yield moles of hydrogen in hydrocarbon sample. H (g) + CaCl (s) CaCl H (s) 3. Convert mass of N to moles of nitrogen atoms. - because there are two moles of nitrogen atoms in one mole of nitrogen molecules, multiply result by to yield moles of nitrogen in hydrocarbon sample. 4. Calculate moles of oxygen in products. - moles of oxygen = moles of C + moles of H 5. Calculate moles of oxygen in hydrocarbon - moles of hydrocarbon oxygen = moles of oxygen atoms in products moles of oxygen atoms used 6. Divide molar amounts by smallest of the values to find molar ratios in terms of whole numbers.
8 Example: Find the empirical formula for a sample of hydrocarbon that produces 7.61 g of C, 4.15 g of H and uses 7.39 g of during combustion. 8 Moles of carbon Moles of hydrogen C C 7.61g 0.173molC 44.0 gc C H mol 18.0 g H 4.15g 0.46 H H H Moles of oxygen in products C mol H mol products 7.61g 4.15g 44.0g 18.0g Moles of oxygen in hydrocarbon C C H H mol mol mol mol hydrocarbon products mol mol 7.39g 3.0g mol 0.46 mol 0.115mol mol Molar ratios 0.173molC 3mol mol mol 0.46H 4 mol mol C H Empirical formula is C3H8
9 THERETICAL STICHIMETRY - coefficients of balanced equations relate moles of reactants to moles of products Example: N (g) + 3 H (g) NH3 (g) mole of N is stoichiometrically equivalent to moles of NH3. - in other words, for every 1 mole of N reacted, moles of NH3 are produced. - N mol NH 3 - equivalence is only true for specific chemical reaction - equivalence can be considered a conversion factor N mol NH 3 N mol NH or mol NH N other equivalences are - N 3molH - 3mol H mol NH 3 The Haber process is essential in the production of fertilizer, which in turn, is essential for sustenance of Earth s 7,000,000,000 people. Example: a) What are all of the stoichiometric equivalences for the reaction, CH (g) + 5 (g) 4 C (g) + H (g)? molch 5mol C H molc CH H 5mol 4molC 5mol mol H mol C H b) How many moles of carbon dioxide are formed when 5 moles of acetylene (CH) is combusted? c) How many moles of oxygen are needed to fully burn 9.8 moles of acetylene (CH)? Acetylene is a welder s fuel.
10 PRACTICAL STICHIMETRY - 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.*** 10 SCHEME: M Molar mass Mass of reactant (g) Mass of product (g) M Molar mass Moles of reactant (mol) Balanced equation Moles of product (mol) Example: For the reaction, NH3 (g) + HCl (g) NH4Cl (s), a) how much NH3 is needed to react with 9.3 g of HCl? 1) First convert grams of reactant to moles of reactant ) Compare moles of one reactant to other reactant. 3) Convert moles of other reactant to grams. The reaction of ammonia with hydrogen chloride gas is used to create a smokescreen. b) How much ammonium chloride is produced when 9.3 g of HCl is fully reacted? - Note with dimensional analysis, we can do problems all on one line.
11 Example: For the reaction 4BaC3 (s) + Y(C3)3 (s) + 6 CuC3 (s) YBaCu37 (s) + 13 C (g) + 3 (g) a) calculate how many grams of CuC3 is needed to fully react with g of BaC3, 11 b) calculate how many grams of YBaCu37 is formed from g of BaC3 fully reacting. Yttrium barium copper oxide (YBC) is a superconducting ceramic. It is superconducting below a temperature of 95 K.
12 1 Example: Epsom salts are used in foot baths to soften skin and relieve itching. Epsom salt is a hydrated crystal of magnesium sulfate. An intense heat source such as a Bunsen burner flame can drive off the water from the crystal leaving the anhydrous salt. Given the data below, write the correct chemical formula for Epsom salt. Mass of beaker Mass of beaker and Epsom salt Mass of beaker and dried salt g g g Find the mass of the Epsom salt g g = g Find the mass of the dried salt g g = 5.48 g Find the mass of water that has left g 5.48 g = g Find the moles of water Find the moles of MgS4 Find the number of water molecules per MgS4 unit The correct chemical formula is MgS4 7 H
13 13 LIMITING REAGENTS - ften starting materials are not available in proper stoichiometric proportions. - Given unbalanced amounts of reactants, we would like to know how much product could be produced. Analogy: Bicycle Factory The equation to make a bicycle is wheels + 1 frame + 1 handlebar 1 bicycle If the parts inventory is as follows: 40 wheels 150 frames 135 handlebars, we ask ourselves - What reactant limits production? - How much product can be produced? Limiting reactant: wheels Production: 10 bicycles ***In limiting reagent problems, we need to compare moles to moles*** - need to convert all masses to moles - To find limiting reactant, calculate number of moles of product formed from each number of moles of reactant - Limiting reactant will yield lowest number of moles produced. (The lowest number of moles produced is the actual number of moles of product produced.) Example: For the reaction S (g) + (g) + H (l) HS4 (aq), if 5.6 mol of S, 4.8 mol of and 6.0 mol of H are reacted together, a) how many moles of HS4 are produced? HS4 For the S: 56. mols 56. mol molhs4 For the : 48. mol 96. mol S H S 4 HS4 H S4 For the H: 6.0 molh 6.0 molh S4 H S is limiting reactant and therefore 5.6 moles of HS4 is produced.
14 b) how much is remaining after reaction is complete? - to answer the question, we need to know how much was used. - then remaining is the amount of reacted subtracted from the starting amount of. used: 56. mols 8. mol mol S remaining = starting used = 4.8 mol.8 mol =.0 mol Sulfur dioxide is a pollutant from burning coal that is a contributor to acid rain. Sulfur dioxide is removed from air with calcium oxide.s (g) + Ca (s) CaS 3 (s) 14 Example: For the reaction Zn (s) + CuCl (aq) ZnCl (aq) + Cu (s) a) How much copper metal is produced from the reaction of.00 g of Zn and.00 g of CuCl? Thus CuCl is the limiting reactant and the amount of copper produced is b) How much reactant was left over? Since CuCl is the limiting reactant, all of it was consumed in the reaction. Thus some Zn is left over. Moles of Zn used Zn molcu mol Total original moles moles used = moles left over Cu Zn
15 15 REACTIN YIELDS - an actual chemical process is rarely perfect - actual yield is less than theoretical perfect yield - we have been calculating theoretical yields - we often want to compare actual yield to theoretical yield Example: For the reaction Cr3 (s) + Al (s) Cr (s) + Al3 (s) 18.7 g of Chromium (III) oxide reacts to form 10.8 g of chromium metal. What the percent yield of this process? % yield Theoretical yield of chromium metal is actual yield 100% theoretical yield Thus the percent yield is
THE 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 informationChapter 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 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 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 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 informationUnit 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 informationThe 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 informationChapter 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 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 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 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 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 informationChem 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 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 catbon-12
More informationHonors 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 informationFormulae, 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 informationChapter 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 informationIB 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 informationChapter 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 informationMoles. 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 informationW1 WORKSHOP ON STOICHIOMETRY
INTRODUCTION W1 WORKSHOP ON STOICHIOMETRY These notes and exercises are designed to introduce you to the basic concepts required to understand a chemical formula or equation. Relative atomic masses of
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 informationThe 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 informationSCH 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 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 informationLecture 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 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 informationUnit 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 informationCalculations 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 informationIB Chemistry. DP Chemistry Review
DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount
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 informationFormulas, 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 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 informationChemical 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 informationMoles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe:
Like a recipe: Balancing Eqns Reactants Products 2H 2 (g) + O 2 (g) 2H 2 O(l) coefficients subscripts Balancing Eqns Balancing Symbols (s) (l) (aq) (g) or Yields or Produces solid liquid (pure liquid)
More informationThe Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon-12? 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 informationChemistry Post-Enrolment Worksheet
Name: Chemistry Post-Enrolment Worksheet The purpose of this worksheet is to get you to recap some of the fundamental concepts that you studied at GCSE and introduce some of the concepts that will be part
More informationChapter 3 Stoichiometry
Chapter 3 Stoichiometry 3-1 Chapter 3 Stoichiometry In This Chapter As you have learned in previous chapters, much of chemistry involves using macroscopic measurements to deduce what happens between atoms
More informationChapter 3. Mass Relationships in Chemical Reactions
Chapter 3 Mass Relationships in Chemical Reactions This chapter uses the concepts of conservation of mass to assist the student in gaining an understanding of chemical changes. Upon completion of Chapter
More informationChem 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 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 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 McGraw-Hill Companies,
More informationGetting the most from this book...4 About this book...5
Contents Getting the most from this book...4 About this book....5 Content Guidance Topic 1 Atomic structure and the periodic table...8 Topic 2 Bonding and structure...14 Topic 2A Bonding....14 Topic 2B
More informationChem 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 informationOther Stoich Calculations A. mole mass (mass mole) calculations. GIVEN mol A x CE mol B. PT g A CE mol A MOLE MASS :
Chem. I Notes Ch. 12, part 2 Using Moles NOTE: Vocabulary terms are in boldface and underlined. Supporting details are in italics. 1 MOLE = 6.02 x 10 23 representative particles (representative particles
More informationChapter 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 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 informationCHAPTER 8: CHEMICAL COMPOSITION
CHAPTER 8: CHEMICAL COMPOSITION Active Learning: 1-4, 6-8, 12, 18-25; End-of-Chapter Problems: 3-4, 9-82, 84-85, 87-92, 94-104, 107-109, 111, 113, 119, 125-126 8.2 ATOMIC MASSES: COUNTING ATOMS BY WEIGHING
More informationStoichiometry. Unit Outline
3 Stoichiometry Unit Outline 3.1 The Mole and Molar Mass 3.2 Stoichiometry and Compound Formulas 3.3 Stoichiometry and Chemical Reactions 3.4 Stoichiometry and Limiting Reactants 3.5 Chemical Analysis
More informationPART 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 information1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams?
Name: Tuesday, May 20, 2008 1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams? 2 5 1. P2O 5 3. P10O4 2. P5O 2 4. P4O10 2. Which substance
More informationBalance 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 informationMASS 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 informationStoichiometry Review
Stoichiometry Review There are 20 problems in this review set. Answers, including problem set-up, can be found in the second half of this document. 1. N 2 (g) + 3H 2 (g) --------> 2NH 3 (g) a. nitrogen
More informationUnit 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 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 carbon-12, 6p + + 6n 0 = atomic mass of 12.0 o For chlorine-35, 17p + + 18n 0 = atomic mass of 35.0 atomic mass
More informationConcept 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 informationThe Mole and Molar Mass
The Mole and Molar Mass 1 Molar mass is the mass of one mole of a substance. Molar mass is numerically equal to atomic mass, molecular mass, or formula mass. However the units of molar mass are g/mol.
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 informationChemistry B11 Chapter 4 Chemical reactions
Chemistry B11 Chapter 4 Chemical reactions Chemical reactions are classified into five groups: A + B AB Synthesis reactions (Combination) H + O H O AB A + B Decomposition reactions (Analysis) NaCl Na +Cl
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 informationStoichiometry. Lecture Examples Answer Key
Stoichiometry Lecture Examples Answer Key Ex. 1 Balance the following chemical equations: 3 NaBr + 1 H 3 PO 4 3 HBr + 1 Na 3 PO 4 2 C 3 H 5 N 3 O 9 6 CO 2 + 3 N 2 + 5 H 2 O + 9 O 2 2 Ca(OH) 2 + 2 SO 2
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 informationEXPERIMENT 12: Empirical Formula of a Compound
EXPERIMENT 12: Empirical Formula of a Compound INTRODUCTION Chemical formulas indicate the composition of compounds. A formula that gives only the simplest ratio of the relative number of atoms in a compound
More informationChemistry 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 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 informationChapter Three: STOICHIOMETRY
p70 Chapter Three: STOICHIOMETRY Contents p76 Stoichiometry - The study of quantities of materials consumed and produced in chemical reactions. p70 3-1 Counting by Weighing 3-2 Atomic Masses p78 Mass Mass
More informationAtomic mass is the mass of an atom in atomic mass units (amu)
Micro World atoms & molecules Laboratory scale measurements Atomic mass is the mass of an atom in atomic mass units (amu) By definition: 1 atom 12 C weighs 12 amu On this scale 1 H = 1.008 amu 16 O = 16.00
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 informationChemical 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 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 informationCalculations with Chemical Formulas and Equations
Chapter 3 Calculations with Chemical Formulas and Equations Concept Check 3.1 You have 1.5 moles of tricycles. a. How many moles of seats do you have? b. How many moles of tires do you have? c. How could
More informationBalancing Chemical Equations
Balancing Chemical Equations Academic Success Center Science Tutoring Area Science Tutoring Area Law of Conservation of Mass Matter cannot be created nor destroyed Therefore the number of each type of
More informationCh. 6 Chemical Composition and Stoichiometry
Ch. 6 Chemical Composition and Stoichiometry The Mole Concept [6.2, 6.3] Conversions between g mol atoms [6.3, 6.4, 6.5] Mass Percent [6.6, 6.7] Empirical and Molecular Formula [6.8, 6.9] Bring your calculators!
More informationHOMEWORK 4A. Definitions. Oxidation-Reduction Reactions. Questions
HOMEWORK 4A Oxidation-Reduction Reactions 1. Indicate whether a reaction will occur or not in each of following. Wtiring a balcnced equation is not necessary. (a) Magnesium metal is added to hydrochloric
More informationChapter 5, Calculations and the Chemical Equation
1. How many iron atoms are present in one mole of iron? Ans. 6.02 1023 atoms 2. How many grams of sulfur are found in 0.150 mol of sulfur? [Use atomic weight: S, 32.06 amu] Ans. 4.81 g 3. How many moles
More informationMolarity of Ions in Solution
APPENDIX A Molarity of Ions in Solution ften it is necessary to calculate not only the concentration (in molarity) of a compound in aqueous solution but also the concentration of each ion in aqueous solution.
More informationChemistry 65 Chapter 6 THE MOLE CONCEPT
THE MOLE CONCEPT Chemists find it more convenient to use mass relationships in the laboratory, while chemical reactions depend on the number of atoms present. In order to relate the mass and number of
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 informationMole 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 informationSample 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 informationCHEMICAL REACTIONS. Chemistry 51 Chapter 6
CHEMICAL REACTIONS A chemical reaction is a rearrangement of atoms in which some of the original bonds are broken and new bonds are formed to give different chemical structures. In a chemical reaction,
More informationChapter 8 How to Do Chemical Calculations
Chapter 8 How to Do Chemical Calculations Chemistry is both a qualitative and a quantitative science. In the laboratory, it is important to be able to measure quantities of chemical substances and, as
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 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 informationSTOICHIOMETRY UNIT 1 LEARNING OUTCOMES. At the end of this unit students will be expected to:
STOICHIOMETRY LEARNING OUTCOMES At the end of this unit students will be expected to: UNIT 1 THE MOLE AND MOLAR MASS define molar mass and perform mole-mass inter-conversions for pure substances explain
More informationMOLECULAR MASS AND FORMULA MASS
1 MOLECULAR MASS AND FORMULA MASS Molecular mass = sum of the atomic weights of all atoms in the molecule. Formula mass = sum of the atomic weights of all atoms in the formula unit. 2 MOLECULAR MASS AND
More information11-1 Stoichiometry. Represents
11-1 Stoichiometry What is stoichiometry? Calculations that relate the quantities of substances. It is the study of quantitative (measurable amounts) relationships in chemical reactions and equations.
More informationUnit 7A - The Mole. We Need to Count atoms. The Mole and Molar Mass
Unit 7A - The Mole The Mole and Molar Mass We Need to Count atoms Airbags are inflated by a chemical reaction: electrical 2 NaN 3 (s) 3 N 2 (g) + 2 Na(s) decomposition Each airbag needs the right amount
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 informationUnit 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 informationstoichiometry = 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 informationGeneral Chemistry I (FC, 09-10) Lab #3: The Empirical Formula of a Compound. Introduction
General Chemistry I (FC, 09-10) Introduction A look at the mass relationships in chemistry reveals little order or sense. The ratio of the masses of the elements in a compound, while constant, does not
More informationChem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Answers
Key Questions & Exercises Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Answers 1. The atomic weight of carbon is 12.0107 u, so a mole of carbon has a mass of 12.0107 g. Why doesn t a mole of
More informationThe Empirical Formula of a Compound
The Empirical Formula of a Compound Lab #5 Introduction A look at the mass relationships in chemistry reveals little order or sense. The ratio of the masses of the elements in a compound, while constant,
More information1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) 3 (s) + H 2 (g)
1. When the following equation is balanced, the coefficient of Al is. Al (s) + H 2 O (l)? Al(OH) (s) + H 2 (g) A) 1 B) 2 C) 4 D) 5 E) Al (s) + H 2 O (l)? Al(OH) (s) + H 2 (g) Al (s) + H 2 O (l)? Al(OH)
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 informationneutrons are present?
AP Chem Summer Assignment Worksheet #1 Atomic Structure 1. a) For the ion 39 K +, state how many electrons, how many protons, and how many 19 neutrons are present? b) Which of these particles has the smallest
More informationTutorial 4 SOLUTION STOICHIOMETRY. Solution stoichiometry calculations involve chemical reactions taking place in solution.
T-27 Tutorial 4 SOLUTION STOICHIOMETRY Solution stoichiometry calculations involve chemical reactions taking place in solution. Of the various methods of expressing solution concentration the most convenient
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 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 information