MOLES AND MOLE CALCULATIONS


 Theodora Smith
 11 months ago
 Views:
Transcription
1 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 is formed. In this section theoretical details are kept to the minimum necessary for a mastery of calculation methods to be achieved. It is desirable, however, that at some stage students learn of the historical development of the ideas applied here, and of the underlying theory. It is assumed that students have a good mastery of basic arithmetic and algebra, especially of calculations involving ratios and proportions. It is assumed also that students are able to both read and write chemical formulae and equations, accurately and with fair confidence. Until such knowledge and skills have been acquired, it is difficult to achieve success with mole calculations. SCOPE OF CLCULTIONS COVERED IN THIS SECTION There are three basic requirements to be mastered in this section: 1) to calculate masses of reactants that will be consumed in a reaction, and the masses of products likely to be formed from a given mass of reactants.. 2) to calculate what volume of gas may be either consumed or produced in a reaction 3) to calculate what volumes and concentrations of solutions of reactants should be mixed to produce predicted concentrations of products in the solution. DEFINITION OF MOLE ND OF MOLR MSS toms of different elements have different masses. It is possible both to measure the mass of individual atoms, and to measure the relative masses of different kinds of atoms. ctual  masses of atoms are very small (an atom of carbon has mass = 2 x 10 g approx), so the masses are given in atomic mass units (amu). The mass of an atom of carbon has been selected as a standard for comparing the masses 1 of atoms: an atom of carbon has been assigned a mass of amu. The relative atomic mass of an atom of any other element is given in proportion to the mass of an atom of carbon. For example, the relative atomic mass of an oxygen atom is given as amu, which indicates that an atom of oxygen is times more massive than an atom of carbon. The relative atomic mass of hydrogen = 1.00 amu; an atom of hydrogen has mass of an atom of carbon. of the 1 The definitions given here do not allow for the existence of different isotopes of elements. This omission does not affect the validity of the methods described. Detailed treatment of this topic should consider the presence of isotopes.
2 36 The relative atomic masses (ram) of some common elements are listed below: Element ram Element ram Element ram luminium 27.0 Gold Oxygen 16.0 Barium Hydrogen 1.0 Phosphorus 31.0 Bromine 79.9 Iodine Potassium 39.1 Calcium 40.1 Iron 55.8 Silicon 28.1 Carbon 12.0 Lead Silver Chlorine 35.5 Magnesium 24.3 Sodium.0 Chromium 52.0 Manganese 54.9 Sulfur 32.1 Cobalt 58.9 Mercury Tin Copper 63.5 Nickel 58.7 Titanium 47.9 Fluorine 19.0 Nitrogen 14.0 Zinc 65.4 The mass of one mole of an element is the relative atomic mass of an element, stated in grams. mole is defined as the number of atoms in g of pure carbon. The value of this number is 6.0 x 10. It is called the vogadro Number, symbol N. One mole of any element also contains 6.0 x 10, or N, atoms. WHT BOUT COMPOUNDS? The mass of one mole of any compound can be calculated by adding the relative atomic masses of all atoms in the formula, and stating the total in grams. Examples: Compound Formula Sum of masses of atoms in formula Mass of one mole Water H2O (1.0 x 2) g Carbon dioxide CO (16.0 x 2) 44.0 g Sodium chloride NaCl g Calcium sulfate CaSO (16.0 x 4) g Lead nitrate Pb(NO 3) ( x 3) g mmonium phosphate (NH 4) 3PO4 3( x 4) (16.0 x 4) g
3 37 The mass of one mole of a substance is the MOLR MSS, for which the symbol is M. One mole of any substance contains N, or 6.0 x 10, of each particle present. Examples: One mole of with formula contains the following numbers of molecules or ions and the following numbers of atoms Water H2O N molecules of water 2 x N atoms of hydrogen, N atoms of oxygen Carbon dioxide CO2 N molecules of carbon dioxide Sodium chloride NaCl N sodium ions and N chloride ions Calcium sulfate CaSO4 N calcium ions and N sulfate ions Lead nitrate Pb(NO 3) 2 N lead ions and 2 x N nitrate ions mmonium phosphate (NH 4) 3PO4 3 x N ammonium ions and N phosphate ions N atoms of carbon, 2 x N atoms of oxygen N atoms of sodium, N atoms of chlorine N atoms of calcium, N atoms of sulfur, 4 x N atoms of oxygen N atoms of lead, 2 x N atoms of nitrogen, 6 x N atoms of oxygen. 3 x N atoms of nitrogen, 12 x N atoms of hydrogen, N atoms of phosphorus, 4 x N atoms of oxygen PERCENTGE COMPOSITION The proportion by mass of an element in a compound can be calculated easily by using molar masses. For example, the proportion of sodium present in sodium chloride, NaCl, is the ratio of the mass of one mole of sodium to the mass of one mole of sodium chloride, expressed as a percentage. Proportion of sodium in sodium chloride = = Percentage composition of sodium in sodium chloride = 39.3%. What is the percentage composition of nitrogen in ammonium nitrate, NH4NO 3? Molar mass of ammonium nitrate = 80.0 g Mass of nitrogen in one mole of ammonium nitrate = 2 x 14.0 g = 28.0 Percentage composiition of nitrogen in ammonium nitrate = = 35.0%.
4 38 USE OF MOLR MSS TO PREDICT RECTING MSSES balanced chemical equation is a way of describing the relative quantities of reactants and products that are involved in a reaction. The coefficients may be read to indicate the relative numbers of atoms, ions, or molecules involved in the reaction. It is more useful to read the coefficients as indicating the numbers of moles of each substance involved. The following equation, for magnesium metal burning in oxygen, can be read "two atoms of magnesium combine with one molecule of oxygen to form two 'molecules' (actually ions Mg and O ) of magnesium oxide." better way to read it is "two moles of magnesium metal combine with one mole of oxygen gas to form two moles of magnesium oxide". From this, the relative masses of the reactants and products can be predicted: 2 moles 1 mole 2 moles 2 x 24.3 g 32.0 g 2 x 40.3 g If the relative masses of reactants and products in a reaction can be predicted from a balanced equation and knowledge of molar masses, then the actual mass of any reactant or product can be calculated by the use of ratios. Example one: What mass of sodium carbonate will be obtained if 3.36 g of pure sodium hydrogencarbonate is heated? (The other products of the reaction are carbon dioxide and water.) 1) Write a balanced equation: 2) Write mole ratios underneath equation: 2 moles 1 mole 3) Calculate molar masses and write them under: 2 x 84.0 g g 4) Write in known value, and "x" for unknown: 3.36 g x g Use ratio to calculate x: = x = = 2.12 g The mass of sodium carbonate formed by heating 3.36 g of sodium hydrogencarbonate = 2.12 g.
5 39 Example two: What mass of carbon will be converted to carbon monoxide in reducing 1000 g of iron(iii) oxide to iron metal? What masses of iron and carbon monoxide should be formed? Note that with three "unknowns" in this problem, three algbraic symbols, x, y, z, are used. The values of x, y, and z are calculated by simple ratio: = = = Mass of carbon converted = x = 226 g Mass of iron formed = y = 700 g Mass of carbon monoxide formed = z = 526 g The total mass of reactants should equal the total mass of products: 1000 g g = 700 g g Example three: What mass of lead can be extracted by heating 120 g of solid lead sulfide in air, forming lead oxide and sulfur dioxide, then heating the lead oxide with carbon, to form metallic lead and carbon monoxide? This problem can be solved as above, by writing the equations and carrying out all ratio calculations. n alternative method uses percentage composition: the problem can be summed up as "how much lead can be separated from 120 g of lead sulfide?" Molar mass of PbS = ( ) g = 9.3 g. Percentage of lead in lead sulfide = = 86.6% 86.6% of 120 g = 104 g = mass of lead that can be extracted from 120 g of lead sulfide. Exercises: 1. What mass of copper can be extracted from 5.0 g of copper(ii) sulfate by dissolving the copper sulfate in water and adding zinc metal? (The other product is zinc sulfate). 2. What mass of potassium iodide is needed to react exactly with 8.0 g of lead nitrate, to form lead iodide? (The other product is potassium nitrate). 3. When calcium carbonate is heated strongly, it forms calcium oxide and carbon dioxide. What mass of calcium carbonate is needed to make 50.0 g of calcium oxide? 4. Sodium carbonate reacts with hydrochloric acid to form sodium chloride, water, and carbon dioxide. Some hydrochloric acid was added to some sodium carbonate: 6.0 g of sodium chloride were formed. What mass of carbon dioxide was produced? 5. What mass of lead oxide would need to be reacted with nitric acid to produce 10.0g of lead nitrate?
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 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 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 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 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 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 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 informationMoles, Molecules, and Grams Worksheet Answer Key
Moles, Molecules, and Grams Worksheet Answer Key 1) How many are there in 24 grams of FeF 3? 1.28 x 10 23 2) How many are there in 450 grams of Na 2 SO 4? 1.91 x 10 24 3) How many grams are there in 2.3
More informationSCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGrawHill Ryerson, 2001
SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGrawHill 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 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 informationChapter 5  Molecules and Compounds
Chapter 5  Molecules and Compounds How do we represent molecules? In pictures In formula In name Ionic compounds Molecular compounds On the course website, you will find a list of ions that I would like
More informationCP 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 informationChemistry PostEnrolment Worksheet
Name: Chemistry PostEnrolment 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 informationFormulae, Equations & Formula Mass
St Peter the Apostle High School Chemistry Department Formulae, Equations & Formula Mass N4 & N5 Homework Questions Answer questions as directed by your teacher. National 4 level questions are first followed
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 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 informationBalancing Chemical Equations Worksheet
Balancing Chemical Equations Worksheet Student Instructions 1. Identify the reactants and products and write a word equation. 2. Write the correct chemical formula for each of the reactants and the products.
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 informationWriting and Balancing Chemical Equations
Name Writing and Balancing Chemical Equations Period When a substance undergoes a chemical reaction, chemical bonds are broken and new bonds are formed. This results in one or more new substances, often
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 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 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 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 informationNumber of moles of solute = Concentration (mol. L ) x Volume of solution (litres) or n = C x V
44 CALCULATIONS INVOLVING SOLUTIONS INTRODUCTION AND DEFINITIONS Many chemical reactions take place in aqueous (water) solution. Quantities of such solutions are measured as volumes, while the amounts
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 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 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 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 informationChapter 3 Stoichiometry
Chapter 3 Stoichiometry 31 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 informationATOMS. Multiple Choice Questions
Chapter 3 ATOMS AND MOLECULES Multiple Choice Questions 1. Which of the following correctly represents 360 g of water? (i) 2 moles of H 2 0 (ii) 20 moles of water (iii) 6.022 10 23 molecules of water (iv)
More informationStoichiometry Review
Stoichiometry Review There are 20 problems in this review set. Answers, including problem setup, can be found in the second half of this document. 1. N 2 (g) + 3H 2 (g) > 2NH 3 (g) a. nitrogen
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 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 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 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 informationWRITING CHEMICAL FORMULA
WRITING CHEMICAL FORMULA For ionic compounds, the chemical formula must be worked out. You will no longer have the list of ions in the exam (like at GCSE). Instead you must learn some and work out others.
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. 352363 See GCSE Chemistry Chapter 5 pg. 7079 6.1 Relative atomic mass. The relative atomic mass
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 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 informationSummer Assignment Coversheet
Summer Assignment Coversheet Course: A.P. Chemistry Teachers Names: Mary Engels Assignment Title: Summer Assignment A Review Assignment Summary/Purpose: To review the Rules for Solubility, Oxidation Numbers,
More informationHOMEWORK 4A. Definitions. OxidationReduction Reactions. Questions
HOMEWORK 4A OxidationReduction 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 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 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 informationCHEMICAL REACTIONS AND REACTING MASSES AND VOLUMES
CHEMICAL REACTIONS AND REACTING MASSES AND VOLUMES The meaning of stoichiometric coefficients: 2 H 2 (g) + O 2 (g) 2 H 2 O(l) number of reacting particles 2 molecules of hydrogen react with 1 molecule
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 informationCHEMICAL FORMULAS AND FORMULA WEIGHT CALCULATIONS
CHEMICAL FORMULAS AND FORMULA WEIGHT CALCULATIONS 1. THE MEANING OF A CHEMICAL FORMULA A chemical formula is a shorthand method of representing the elements in a compound. The formula shows the formulas
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 informationHonors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C4.4)
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 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 informationUnit 2: Quantities in Chemistry
Mass, Moles, & Molar Mass Relative quantities of isotopes in a natural occurring element (%) E.g. Carbon has 2 isotopes C12 and C13. Of Carbon s two isotopes, there is 98.9% C12 and 11.1% C13. Find
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 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 information111 Stoichiometry. Represents
111 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 informationPeriodic Table, Valency and Formula
Periodic Table, Valency and Formula Origins of the Periodic Table Mendelѐѐv in 1869 proposed that a relationship existed between the chemical properties of elements and their atomic masses. He noticed
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 informationCHEM 120 Online: Chapter 6 Sample problems Date: 2. Which of the following compounds has the largest formula mass? A) H2O B) NH3 C) CO D) BeH2
CHEM 120 Online: Chapter 6 Sample problems Date: 1. To determine the formula mass of a compound you should A) add up the atomic masses of all the atoms present. B) add up the atomic masses of all the atoms
More informationChapter 6 OxidationReduction Reactions. Section 6.1 2. Which one of the statements below is true concerning an oxidationreduction reaction?
Chapter 6 OxidationReduction Reactions 1. Oxidation is defined as a. gain of a proton b. loss of a proton c. gain of an electron! d. loss of an electron e. capture of an electron by a neutron 2. Which
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 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 informationTopic 4 National Chemistry Summary Notes. Formulae, Equations, Balancing Equations and The Mole
Topic 4 National Chemistry Summary Notes Formulae, Equations, Balancing Equations and The Mole LI 1 The chemical formula of a covalent molecular compound tells us the number of atoms of each element present
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 informationDescription of the Mole Concept:
Description of the Mole Concept: Suppose you were sent into the store to buy 36 eggs. When you picked them up you would get 3 boxes, each containing 12 eggs. You just used a mathematical device, called
More informationCalculating Molar Mass of a Compound
Instructions for Conversion Problems For every conversion problem Write the number in the problem down with unit and a multiplication sign Decide which conversion factor you should use, Avagadro s or molar
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 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 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 informationMolecular Formula: Example
Molecular Formula: Example A compound is found to contain 85.63% C and 14.37% H by mass. In another experiment its molar mass is found to be 56.1 g/mol. What is its molecular formula? 1 CHAPTER 3 Chemical
More informationChapter 12 Stoichiometry
Chapter 12 Stoichiometry I. How much can a reaction produce? (12.1) A. Proportional Relationships 1. like recipes 2. how much can I get? 3. how much do I need? Stoichiometry: mass and quantity relationships
More informationMolar Mass Worksheet Answer Key
Molar Mass Worksheet Answer Key Calculate the molar masses of the following chemicals: 1) Cl 2 71 g/mol 2) KOH 56.1 g/mol 3) BeCl 2 80 g/mol 4) FeCl 3 162.3 g/mol 5) BF 3 67.8 g/mol 6) CCl 2 F 2 121 g/mol
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 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 informationChemistry: Chemical Equations
Chemistry: Chemical Equations Write a balanced chemical equation for each word equation. Include the phase of each substance in the equation. Classify the reaction as synthesis, decomposition, single replacement,
More informationDiagnostic/Introductory Activity. Word Search
Diagnostic/Introductory Activity Find any 10 of the first 20 elements. Word Search Q H Z S B N Q J B C N P K M A A M M O O A O E C H E H H U A T L R U X D R E V L G O N I D I O U E I Y I Z N O O S M L
More informationAtomic Theory: The Nuclear Model of the Atom
Chapter 5 Atomic Theory: The Nuclear Model of the Atom Section 5.1 Dalton s Atomic Theory Goal 1 Precursors to John Dalton s atomic theory Law of Definite Composition The percentage by mass of the elements
More informationProblem Solving. Percentage Composition
Skills Worksheet Problem Solving Percentage Composition Suppose you are working in an industrial laboratory. Your supervisor gives you a bottle containing a white crystalline compound and asks you to determine
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 informationLearning Guide 3A Salts Chem 1010. If you could look at them more closely, here's what you would see.
Introduction Learning Guide 3A Salts Chem 1010 Look at the samples in the two bottles you were given. What observations can you make about them? A: B: If you could look at them more closely, here's what
More informationTutorial 4 SOLUTION STOICHIOMETRY. Solution stoichiometry calculations involve chemical reactions taking place in solution.
T27 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 informationBALANCING CHEMICAL EQUATIONS
BALANCING CHEMICAL EQUATIONS The Conservation of Matter states that matter can neither be created nor destroyed, it just changes form. If this is the case then we must account for all of the atoms in a
More informationProblem Solving. Mole Concept
Skills Worksheet Problem Solving Mole Concept Suppose you want to carry out a reaction that requires combining one atom of iron with one atom of sulfur. How much iron should you use? How much sulfur? When
More informationUnit 9 Compounds Molecules
Unit 9 Compounds Molecules INTRODUCTION Compounds are the results of combinations of elements. These new substances have unique properties compared to the elements that make them up. Compounds are by far
More informationSolution. Practice Exercise. Concept Exercise
Example Exercise 8.1 Evidence for a Reaction Which of the following is experimental evidence for a chemical reaction? (a) Pouring vinegar on baking soda gives foamy bubbles. (b) Mixing two solutions produces
More informationChemistry Assessment Unit AS 1
Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2014 Chemistry Assessment Unit AS 1 assessing Basic Concepts in Physical and Inorganic Chemistry AC112
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 1024 g Atomic weight: Average mass of all isotopes of a given
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 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 informationExperiment 5. Chemical Reactions A + X AX AX A + X A + BX AX + B AZ + BX AX + BZ
Experiment 5 Chemical Reactions OBJECTIVES 1. To observe the various criteria that are used to indicate that a chemical reaction has occurred. 2. To convert word equations into balanced inorganic chemical
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 informationName Date Class STOICHIOMETRY. SECTION 12.1 THE ARITHMETIC OF EQUATIONS (pages 353 358)
Name Date Class 1 STOICHIOMETRY SECTION 1.1 THE ARITHMETIC OF EQUATIONS (pages 353 358) This section explains how to calculate the amount of reactants required or product formed in a nonchemical process.
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 informationMoles Lab mole. 1 mole = 6.02 x 1023. This is also known as Avagadro's number Demo amu amu amu
Moles I. Lab: Rice Counting II. Counting atoms and molecules I. When doing reactions chemists need to count atoms and molecules. The problem of actually counting individual atoms and molecules comes from
More informationEnglish already has many collective nouns for fixed, given numbers of objects. Some of the more common collective nouns are shown in Table 7.1.
96 Chapter 7: Calculations with Chemical Formulas and Chemical Reactions Chemical reactions are written showing a few individual atoms or molecules reacting to form a few atoms or molecules of products.
More informationChapter 16: Tests for ions and gases
The position of hydrogen in the reactivity series Hydrogen, although not a metal, is included in the reactivity series because it, like metals, can be displaced from aqueous solution, only this time the
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 1024 g How many 12 C atoms weigh 12 g?
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 informationSample Exercise 2.1 Illustrating the Size of an Atom
Sample Exercise 2.1 Illustrating the Size of an Atom The diameter of a US penny is 19 mm. The diameter of a silver atom, by comparison, is only 2.88 Å. How many silver atoms could be arranged side by side
More informationCHAPTER 4: MATTER & ENERGY
CHAPTER 4: MATTER & ENERGY Problems: 1,3,5,7,13,17,19,21,23,25,27,29,31,33,37,41,43,45,47,49,51,53,55,57,59,63,65,67,69,77,79,81,83 4.1 Physical States of Matter Matter: Anything that has mass and occupies
More informationCHM101A Exam 2 Version 1 October 10, 2006
CHM101A Exam 2 Version 1 1. Which of the following statements is incorrect? A. SF 4 has ¼ as many sulfur atoms as fluorine atoms. B. Ca(NO 3 ) 2 has six times as many oxygen atoms as calcium ions. C.
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 information