Percent Composition. Percent Composition the percentage by mass of each element in a compound. Percent = Part Whole x 100%


 Alban Clarke
 1 years ago
 Views:
Transcription
1 Percent Composition Percent Composition the percentage by mass of each element in a compound Percent = Part Whole x 100% Percent composition of a compound or = molecule Mass of element in 1 mol x 100% Mass of 1 mol
2 Percent Composition Example: What is the percent composition of Potassium Permanganate (KMnO 4 )? Molar Mass of KMnO 4 K = 1(39.1) = 39.1 Mn = 1(54.9) = 54.9 O = 4(16.0) = 64.0 MM = 158 g
3 Percent Composition Example: What is the percent composition of Potassium Permanganate (KMnO 4 )? Molar Mass of KMnO 4 = 158 g K = 1(39.10) = 39.1 Mn = 1(54.94) = 54.9 O = 4(16.00) = 64.0 MM = 158 % K % Mn 39.1 g K 158 g 54.9 g Mn 158 g % O 64.0 g O 158 g x 100 = 24.7 % x 100 = 34.8 % x 100 = 40.5 %
4 Percent Composition Determine the percentage composition of sodium carbonate (Na 2 CO 3 )? Molar Mass Na = 2(23.00) = 46.0 C = 1(12.01) = 12.0 O = 3(16.00) = 48.0 MM= 106 g Percent Composition % Na = 46.0 g 106 g % C = 12.0 g 106 g % O = 48.0 g 106 g x 100% = 43.4 % x 100% = 11.3 % x 100% = 45.3 %
5 Percent Composition Determine the percentage composition of ethanol (C 2 H 5 OH)? % C = 52.13%, % H = 13.15%, % O = 34.72% Determine the percentage composition of sodium oxalate (Na 2 C 2 O 4 )? % Na = 34.31%, % C = 17.93%, % O = 47.76%
6 Percent Composition Calculate the mass of bromine in 50.0 g of Potassium bromide. 1. Molar Mass of KBr 2. K = 1(39.10) = Br =1(79.90) =79.90 MM = g g = x 50.0g = 33.6 g Br
7 Percent Composition Calculate the mass of nitrogen in 85.0 mg of the amino acid lysine, C 6 H 14 N 2 O Molar Mass of C 6 H 14 N 2 O 2 C = 6(12.01) = H =14(1.01) = N = 2(14.01) = O = 2(16.00) = MM = g g = x 85.0 mg = 16.3 mg N
8 Hydrates Hydrated salt salt that has water molecules trapped within the crystal lattice Examples: CuSO 4 5H 2 O, CuCl 2 2H 2 O Anhydrous salt salt without water molecules Examples: CuCl 2 Can calculate the percentage of water in a hydrated salt.
9 Percent Composition Calculate the percentage of water in sodium carbonate decahydrate, Na 2 CO 3 10H 2 O. 1. Molar Mass of Na 2 CO 3 10H 2 O Na = 2(22.99) = C = 1(12.01) = H = 20(1.01) = 20.2 O = 13(16.00)= MM = Water H = 20(1.01) = 20.2 O = 10(16.00)= MM = or H = 2(1.01) = 2.02 O = 1(16.00) = MM H2O = g g So 10 H 2 O = 10(18.02) = x 100%= %
10 Percent Composition Calculate the percentage of water in Aluminum bromide hexahydrate, AlBr 3 6H 2 O. 1. Molar Mass of AlBr 3 6H 2 O Al = 1(26.98) = Br = 3(79.90) = H = 12(1.01) = O = 6(16.00) = or MM = Water H = 12(1.01) = 12.1 O = 6(16.00)= MM = MM = For 6 H2O = 6(18.02) = g g x 100%= %
11 Percent Composition If 125 grams of magnesium sulfate heptahydrate is completely dehydrated, how many grams of anhydrous magnesium sulfate will remain? MgSO. 4 7 H 2 O 1. Molar Mass Mg = 1 x = g S = 1 x = g O = 4 x = g MM = g H = 2 x 1.01 = 2.02 g O = 1 x = g MM = g MM H 2 O = 7 x g = g Total MM = g g = g 2. % MgSO g g X 100 = % 3. Grams anhydrous MgSO x 125 = 61.1 g
12 Percent Composition If 145 grams of copper (II) sulfate pentahydrate is completely dehydrated, how many grams of anhydrous copper sulfate will remain? CuSO. 4 5 H 2 O 1. Molar Mass Cu = 1 x = g S = 1 x = g O = 4 x = g MM = g H = 2 x 1.01 = 2.02 g O = 1 x = g MM = g MM H 2 O = 5 x g = 90.1 g Total MM = g g = g 2. % CuSO g g X 100 = % 3. Grams anhydrous CuSO x 145 = 92.7 g
13 Percent Composition A 5.0 gram sample of a hydrate of BaCl 2 was heated, and only 4.3 grams of the anhydrous salt remained. What percentage of water was in the hydrate? 1. Amount water lost 2. Percent of water 5.0 g hydrate g anhydrous salt 0.7 g water 0.7 g water 5.0 g hydrate x 100 = 14 %
14 Percent Composition A 7.5 gram sample of a hydrate of CuCl 2 was heated, and only 5.3 grams of the anhydrous salt remained. What percentage of water was in the hydrate? 1. Amount water lost 2. Percent of water 7.5 g hydrate g anhydrous salt 2.2 g water 2.2 g water 7.5 g hydrate x 100 = 29 %
15 Percent Composition A 5.0 gram sample of Cu(NO 3 ) 2 nh 2 O is heated, and 3.9 g of the anhydrous salt remains. What is the value of n? 1. Amount water lost 5.0 g hydrate g anhydrous salt 1.1 g water 3. Amount of water 0.22 x = Percent of water 1.1 g water 5.0 g hydrate x 100 = 22 %
16 Percent Composition A 7.5 gram sample of CuSO 4 nh 2 O is heated, and 5.4 g of the anhydrous salt remains. What is the value of n? 1. Amount water lost 7.5 g hydrate g anhydrous salt 2.1 g water 3. Amount of water 0.28 x = Percent of water 2.1 g water 7.5 g hydrate x 100 = 28 %
17 Empirical and Molecular Formulas
18 Empirical Formula Empirical Formula A formula that gives the simplest wholenumber ratio of the atoms of each element in a compound. Molecular Formula H 2 O 2 C 6 H 12 O 6 CH 3 O CH 3 OOCH = C 2 H 4 O 2 Empirical Formula HO CH 2 O CH 3 O CH 2 O
19 EMPIRICAL FORMULA Mass % of elements Empirical Formula Assume 100g sample Calculate mole ratio Grams of each element Use Atomic Masses Moles of each element
20 What is an empirical formula? A chemical formula in which the ratio of the elements are in the lowest terms is called an empirical formula.
21 Example: The empirical formula for a glucose molecule (C 6 H 12 O 6 ) is CH 2 O. All the subscripts are divisible by six. C 6 H 12 O C H 2 O
22 Exceptions: Some formulas, such as the one for carbon dioxide, CO 2, are already empirical formulas without being reduced.
23 Determine the empirical formula for a compound containing g Cl and g Ca. Steps 1. Find mole amounts. 2. Divide each mole by the smallest mole.
24 1. Find mole amounts g Cl x 1 mol Cl = mol Cl g Cl g Ca x 1 mol Ca = mol Ca g Ca
25 2. Divide each mole by the smallest mole. Cl = mol Cl = 2.00 mol Cl Ca = mol Ca = 1.00 mol Ca Ratio 1 Ca: 2 Cl Empirical Formula = CaCl 2
26 A compound weighing g consists of 72.2% magnesium and 27.8% nitrogen by mass. What is the empirical formula? Hint Percent to mass Mass to mole Divide by small Multiply til whole
27 A compound weighing g consists of 72.2% magnesium and 27.8% nitrogen by mass. What is the empirical formula? Percent to mass: Mg (72.2%/100)* g = g N (27.8%/100)* g = g Mass to mole: Mg g * ( 1 mole ) = 8.86 mole 24.3 g N g * ( 1 mole ) = 5.92 mole g Divide by small: Mg mole/5.92 mole = 1.50 N mole/5.92 mole = 1.00 mole Multiply til whole: Mg 1.50 x 2 = 3.00 N 1.00 x 2 = 2.00 Mg 3 N 2
28 Molecular Formula The molecular formula gives the actual number of atoms of each element in a molecular compound. Steps 1. Find the empirical formula. 2. Calculate the Empirical Formula Mass. 3. Divide the molar mass by the EFM. 4. Multiply empirical formula by factor. Find the molecular formula for a compound whose molar mass is ~ and empirical formula is CH 2 O EFM = g /62.03 = (CH 2 O 3 ) = C 2 H 4 O 6
29 What is a molecular formula? A molecular formula is the true formula of a compound. The chemical formula for a molecular compound shows the actual number of atoms present in a molecule.
30 To find the molecular formula from the empirical formula: Find the empirical formula. Determine the empirical formula mass. Divide the molecular mass by the empirical formula mass to determine the multiple. Multiply the empirical formula by the multiple to find the molecular formula. MF mass EF mass = n (EF)n = molecular formula
31 EXAMPLE: The empirical formula for ethylene is CH 2. molecular formula if the molecular mass is 28.1g/mol. C = 1 x 12 = 12 H = 2 x 1 = +2 14g/mol = empirical formula mass Find the 28.1 g/mol = 2 14 g/mol (CH 2 ) 2 C 2 H 4
32 Find the molecular formula for a compound that contains 4.90 g N and 11.2 g O. The molar mass of the compound is 92.0 g/mol. Steps 1. Find the empirical formula. 2. Calculate the Empirical Formula Mass. 3. Divide the molar mass by the EFM. 4. Multiply empirical formula by factor.
33 Empirical formula. A. Find mole amounts g N x 1 mol N = mol N g N 11.2 g O x 1 mol O = mol O g O
34 B. Divide each mole by the smallest mole. N = = 1.00 mol N O = = 2.00 mol O Empirical Formula = NO 2 Empirical Formula Mass = g/mol
35 Molecular formula Molar Mass = 92.0 g/mol = 2.00 Emp. Formula Mass g/mol Molecular Formula = 2 x Emp. Formula = N 2 O 4
36 A g compound containing only carbon, hydrogen, and oxygen is found to be 48.38% carbon and 8.12% hydrogen by mass. The molar mass of this compound is known to be ~ g/mol. What is its molecular formula?
37 A g compound containing only carbon, hydrogen, and oxygen is found to be 48.38% carbon and 8.12% hydrogen by mass. The molar mass of this compound is known to be ~ g/mol. What is its molecular formula? g C (48.38/100)* g = g g H (8.12/100)* g = g g O (43.5/100)* g = g mole C g * ( 1 mole ) = mol g mole H g * ( 1 mole ) = mol 1.01 g mole O g * ( 1 mole ) = mol g
38 A g compound containing only carbon, hydrogen, and oxygen is found to be 48.38% carbon and 8.12% hydrogen by mass. The molar mass of this compound is known to be ~ g/mol. What is its molecular formula? From last slide: mol C, mol H, mol O C 21.29/14.27 = 1.49 H 42.49/14.27 = 2.98 (esentially 3) O 14.27/14.27 = 1.00 C 1.49 x 2 = 3 H 3 x 2 = 6 C 3 H 6 O 2 O 1 x 2 = 2
39 A g compound containing only carbon, hydrogen, and oxygen is found to be 48.38% carbon and 8.12% hydrogen by mass. The molar mass of this compound is known to be ~ g/mol. What is its molecular formula? From last slide: Empirical formula = C 3 H 6 O 2 EFM = Molar mass = = ~3 EFM (C 3 H 6 O 2 ) = C 9 H 18 O 6
40 Proportional Relationships 2 1/4 c. flour 1 tsp. baking soda 1 tsp. salt 1 c. butter 3/4 c. sugar 3/4 c. brown sugar 1 tsp vanilla extract 2 eggs 2 c. chocolate chips Makes 5 dozen cookies. I have 5 eggs. How many cookies can I make? 5 eggs 5 doz. 2 eggs Courtesy Christy Johannesson Ratio of eggs to cookies = 12.5 dozen cookies
41 Proportional Relationships Stoichiometry mass relationships between substances in a chemical reaction based on the mole ratio Mole Ratio indicated by coefficients in a balanced equation 2 Mg + O 2 2 MgO Courtesy Christy Johannesson
42 Stoichiometry Steps 1. Write a balanced equation. 2. Identify known & unknown. 3. Line up conversion factors. Mole ratio  moles moles Mole Molar ratio mass   moles moles moles grams Molarity  moles liters soln Molar volume  moles liters gas Core step in all stoichiometry problems!! 4. Check answer. Courtesy Christy Johannesson
43 Molar Volume at STP 1 mol of a gas=22.4 L at STP Standard Temperature & Pressure 0 C and 1 atm Courtesy Christy Johannesson
44 Molar Volume at STP LITERS OF GAS AT STP Molar Volume (22.4 L/mol) MASS IN GRAMS Molar Mass (g/mol) MOLES particles/mol NUMBER OF PARTICLES Molarity (mol/l) LITERS OF SOLUTION Courtesy Christy Johannesson
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 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 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 information1. 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 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 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 informationChemistry I: Using Chemical Formulas. Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu.
Chemistry I: Using Chemical Formulas Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu. Molar Mass  The mass in grams of 1 mole of a substance. Substance
More 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 information10.3 Percent Composition and Chemical Formulas. Chapter 10 Chemical Quantities Percent Composition and Chemical Formulas
Chapter 10 Chemical Quantities 101 The Mole: A Measurement of Matter 102 MoleMass and MoleVolume Relationships 103 Percent Composition and Chemical Formulas 1 CHEMISTRY & YOU What does the percent composition
More 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 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 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 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 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. 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 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 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 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 informationPercent Composition, Empirical and Molecular Formulas
Percent Composition, Empirical and Molecular Formulas Chemists create new compounds for industry, pharmaceutical, and home use Analytical chemist analyzes new compound to provide proof of composition and
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 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 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 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 informationMOLAR MASS AND MOLECULAR WEIGHT Themolar mass of a molecule is the sum of the atomic weights of all atoms in the molecule. Molar Mass.
Counting Atoms Mg burns in air (O 2 ) to produce white magnesium oxide, MgO. How can we figure out how much oxide is produced from a given mass of Mg? PROBLEM: If If 0.200 g of Mg is is burned, how much
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 information0.786 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 informationChapter 3. Molecules, Compounds, and Chemical Composition
Chapter 3 Molecules, Compounds, and Chemical Composition Elements and Compounds Elements combine together to make an almost limitless number of compounds. The properties of the compound are totally different
More 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 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 informationMOLE 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 information602X10 21 602,000,000,000, 000,000,000,000 6.02X10 23. Pre AP Chemistry Chemical Quan44es: The Mole. Diatomic Elements
Pre AP Chemistry Chemical Quan44es: The Mole Mole SI unit of measurement that measures the amount of substance. A substance exists as representa9ve par9cles. Representa9ve par9cles can be atoms, molecules,
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 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 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 informationChemical Reactions. Chemical Equations. Mole as Conversion Factor: To convert between number of particles and an equivalent number of moles:
Quantities of Reactants and Products CHAPTER 3 Chemical Reactions Stoichiometry Application of The Law of Conservation of Matter Chemical bookkeeping Chemical Equations Chemical equations: Describe proportions
More informationThe Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon12? Molar Mass of Atoms 3/1/2015
The Mole Chapter 10 1 Objectives Use the mole and molar mass to make conversions among moles, mass, and number of particles Determine the percent composition of the components of a compound Calculate empirical
More 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 information2 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 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 calculations
Chemical calculations Stoichiometry refers to the quantities of material which react according to a balanced chemical equation. Compounds are formed when atoms combine in fixed proportions. E.g. 2Mg +
More informationTest 3 Formula and math of formula review. 2. The oxide of metal X has the formula XO. Which group in the Periodic Table contains metal X?
Name: Sunday, November 04, 2007 Test 3 Formula and math of formula review 1. Which is an example of a binary compound? 1. acetic acid 3. potassium hydroxide 2. nitric acid 4. potassium oxide 2. The oxide
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 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 informationStoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.
Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven
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 informationChapter 10 Chemical Quantities
Chapter 10 Chemical Quantities 101 The Mole: A Measurement 102 MoleMass and MoleVolume Relationships 103 Percent Composition and Chemical Formulas 1 Copyright Pearson Education, Inc, or its affiliates
More 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 information1. The percent by mass of nitrogen in Mg(CN) 2 is equal to 1) 3)
1. The percent by mass of nitrogen in Mg(CN) 2 is equal to 2. A compound consists of 40.% sulfur and 60.% oxygen by mass. What is the empirical formula of this compound? 1) SO 2) SO 2 3) SO 3 4) SO 4 3.
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 informationThe Mole Notes. There are many ways to or measure things. In Chemistry we also have special ways to count and measure things, one of which is the.
The Mole Notes I. Introduction There are many ways to or measure things. In Chemistry we also have special ways to count and measure things, one of which is the. A. The Mole (mol) Recall that atoms of
More 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 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 informationChapter 6 Notes. Chemical Composition
Chapter 6 Notes Chemical Composition Section 6.1: Counting By Weighing We can weigh a large number of the objects and find the average mass. Once we know the average mass we can equate that to any number
More informationThe Mole Concept. A. Atomic Masses and Avogadro s Hypothesis
The Mole Concept A. Atomic Masses and Avogadro s Hypothesis 1. We have learned that compounds are made up of two or more different elements and that elements are composed of atoms. Therefore, compounds
More 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 informationCHAPTER 8: CHEMICAL COMPOSITION
CHAPTER 8: CHEMICAL COMPOSITION Active Learning: 14, 68, 12, 1825; EndofChapter Problems: 34, 982, 8485, 8792, 94104, 107109, 111, 113, 119, 125126 8.2 ATOMIC MASSES: COUNTING ATOMS BY WEIGHING
More 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 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 informationChapter 4. Chemical Composition. Chapter 4 Topics H 2 S. 4.1 Mole Quantities. The Mole Scale. Molar Mass The Mass of 1 Mole
Chapter 4 Chemical Composition Chapter 4 Topics 1. Mole Quantities 2. Moles, Masses, and Particles 3. Determining Empirical Formulas 4. Chemical Composition of Solutions Copyright The McGrawHill Companies,
More 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 informationMole Concept and Stoichiometry
1 Mole Concept and Stoichiometry Concept Mole Concept Introduction This is our common experience that when we go to market to buy something, a few things we always get in definite numbers. For example,
More informationElement of same atomic number, but different atomic mass o Example: Hydrogen
Atomic mass: p + = protons; e  = electrons; n 0 = neutrons p + + n 0 = atomic mass o For carbon12, 6p + + 6n 0 = atomic mass of 12.0 o For chlorine35, 17p + + 18n 0 = atomic mass of 35.0 atomic mass
More informationChapter 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 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 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 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 information1. What is the molecular formula of a compound with the empirical formula PO and a grammolecular 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 grammolecular mass of 284 grams? 2 5 1. P2O 5 3. P10O4 2. P5O 2 4. P4O10 2. Which substance
More informationCHAPTER 3 COMPOUNDS AND MOLECULES
Chapter 3 Compounds and Molecules Page 1 CHAPTER 3 COMPOUNDS AND MOLECULES 31. Octane, a component of gasoline, has eight carbon atoms and eighteen hydrogen atoms per molecule. Its formula is written
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 informationMole Calculations Multiple Choice Review PSI Chemistry
Mole Calculations Multiple Choice Review PSI Chemistry Name The Mole and Avogadro's Number 1)What is the SI unit for measurement of number of particles in a substance? A) kilogram B) ampere C) candela
More informationUnit 4 Conservation of Mass and Stoichiometry
9.1 Naming Ions I. Monatomic Ions A. Monatomic ions 1. Ions formed from a single atom Unit 4 Conservation of Mass and Stoichiometry B. Naming Monatomic Ions 1. Monatomic cations are a. Identified by the
More informationUnit 6. Chapter 10: The MOLE! Date In Class Homework. % Composition & Calculating Empirical Formulas
Date In Class Homework 10/22 Thur Counting By Mass Lab 10/23 Fri (mole day!!!) THE MOLE! in room 137 10/26 Mon (LSM) More on the Mole Watch empirical and molecular formula video. 10/27 Tue % Composition
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 informationLiquid phase. Balance equation Moles A Stoic. coefficient. Aqueous phase
STOICHIOMETRY Objective The purpose of this exercise is to give you some practice on some Stoichiometry calculations. Discussion The molecular mass of a compound is the sum of the atomic masses of all
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 informationModule Three Characterizing Compounds Using Mass Percents and Empirical Formulas. Chem 170. Stoichiometric Calculations.
Chem 170 Stoichiometric Calculations Module Three Characterizing Compounds Using Mass Percents and Empirical Formulas DePauw University Department of Chemistry and Biochemistry Page 1 Introduction to Module
More informationChapter 6: Chemical Composition
C h e m i s t r y 1 2 C h 6 : C h e m i c a l C o m p o s i t i o n P a g e 1 Chapter 6: Chemical Composition Bonus: 17, 21, 31, 39, 43, 47, 55, 61, 63, 69, 71, 77, 81, 85, 91, 95, 97, 99 Check the deadlines
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 informationReview for Final and Second Quarter Benchmark
Review for Final and Second Quarter Benchmark Balance the following Reactions 1. 4Al + 3O 2 2Al 2 O 3 2. 3Ca + N 2 Ca 3 N 2 3. Mg + 2AgNO 3 2Ag + Mg(NO 3 ) 2 4. 2Al + 3CuCl 2 2AlCl 3 + 3Cu 5. What is the
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 informationThe Mole IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES
The Mole S 6.02 X 10 23 IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES Relative Masses To understand relative scales, let s s ignore electrons and compare atoms by total number of nuclear particles. Hydrogen,
More 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 information2. The percent yield is the maximum amount of product that can be produced from the given amount of limiting reactant.
UNIT 6 stoichiometry practice test True/False Indicate whether the statement is true or false. moles F 1. The mole ratio is a comparison of how many grams of one substance are required to participate in
More informationStoichiometry. 1. The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 0.1; (4) 0.2.
Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven
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 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 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 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 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 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 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 informationStoichiometry. Web Resources Chem Team Chem Team Stoichiometry. Section 1: Definitions Define the following terms. Average Atomic mass  Molecule 
Web Resources Chem Team Chem Team Section 1: Definitions Define the following terms Average Atomic mass  Molecule  Molecular mass  Moles  Avagadro's Number  Conservation of matter  Percent composition
More information10.3 Percent Composition and Chemical Formulas
Name Class Date 10.3 Percent Composition and Chemical Formulas Essential Understanding of its empirical formula. A molecular formula of a compound is a wholenumber multiple Lesson Summary Percent Composition
More informationUseful only for measuring the mass of very small objects atoms and molecules!
Chapter 9 Chemical Composition (Moles) Which weighs more, 1 atom of He or 1 atom of O? Units of mass: Pound Kilogram Atomic mass unit (AMU) There are others! 1 amu = 1.66 x 1024 grams = mass of a proton
More informationWe know from the information given that we have an equal mass of each compound, but no real numbers to plug in and find moles. So what can we do?
How do we figure this out? We know that: 1) the number of oxygen atoms can be found by using Avogadro s number, if we know the moles of oxygen atoms; 2) the number of moles of oxygen atoms can be found
More information75.5. Translate chemical symbols and the chemical formulas of common substances to show the component parts of the substances including:
75.5 Translate chemical symbols and the chemical formulas of common substances to show the component parts of the substances including: NaCl [salt], H 2 O [water], C 6 H 12 O 6 [simple sugar], O 2 [oxygen
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 informationProgramme in mole calculation
Programme in mole calculation Step 1 Start at the very beginning Atoms are very small indeed! If we draw a line 1 metre long, 6,000,000,000 (6 billion) atoms could be lined end to end. So a scientist cannot
More informationCONSERVATION OF MASS During a chemical reaction, matter is neither created nor destroyed.  i. e. the number of atoms of each element remains constant
1 CHEMICAL REACTINS Example: Hydrogen + xygen Water H + H + +  Note there is not enough hydrogen to react with oxygen  It is necessary to balance equation. reactants products + H + H (balanced equation)
More informationChapter 1 The Atomic Nature of Matter: Selected Answersc for Practice Exam.
Chapter 1 The Atomic Nature of Matter: Selected Answersc for Practice Exam. MULTIPLE CHOICE 50. 5.80 g of dioxane (C 4 H 8 O 2 ) is how many moles of dioxane? 0.0658 mol 0.0707 mol 0.0725 mol d. 0.0804
More information