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

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

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

Transcription

1 Stoichiometry Chemistry 1010 Review Tutorial Stoichiometry and Lewis Structures April 9 th, 2013 Stoichiometry Stoichiometry involves MOLES Elements/compounds can only be compared side by side using moles 1 mol = individual particles (Avogadro s #) applies to anything We cannot compare masses (or other properties) as they differ for each element or compound Types of Problems Mass Percent and Percent Composition Empirical and Molecular Formulas Combustion Analysis Dry Stoichiometry Percent Yield Limiting Reagent Titration (solution stoichiometry) 1

2 Mass Percent Mass Percent Example To find the mass percent of a particular element in a compound: Find the molar mass of the compound Find the TOTAL mass of the element in question in the compound Divide the mass of element by the mass of compound and multiply by 100 Find the mass percent of each element in C 6 H 12 O 6 Mass Element 100% = Percent Composition Mass Compound Empirical Formula from % Empirical Formula from % To find the empirical formula given percent composition: Assume 100g of sample (MUST state this!) With this assumption, percentages for each element equate to masses in grams Convert each mass to number of moles by diving by molar mass Divide each number of moles by the smallest number of moles to get a simple whole number ratio If you get a decimal, helpful to convert to a fraction Then you can see what number you have to multiply each fraction by 2

3 Empirical Formula Example Butanoate is 58.8% carbon, 9.87% hydrogen, and 31.3% oxygen by mass. What is its empirical formula? Don t forget you can t compare masses! Must look at moles! Molecular Formulas Normally, you will use the empirical formula provided, or one determined in a previous question The molecular mass of the compound will be provided Find the molar mass of the empirical formula: how many empirical formulas make up the molecular formula? Molecular Formulas Molecular Formula Example Molecular Mass Empirical Mass = Whole Number Ratio (Empirical) whole # = Molecular If you don t find a whole number, CHECK your work! A compound has the empirical formula CH 2 O. Its molar mass was determined to be g/mol. What is its molecular formula? 3

4 Combustion Analysis You will be given the mass of an unknown compound (generally containing only C, H, and O) and told it is burned The masses of H 2 O and CO 2 (which are always products of combustion) produced will also be provided Since all C and H from compound form CO 2 and H 2 O, you can determine their amounts Combustion Analysis To find the empirical formula of unknown: Determine moles of CO 2 and H 2 O produced Moles = Mass/Molar Mass Find moles of C and H alone Molar ratios (eg. 1 mol C per mol CO 2 ) Turn moles of C and H into masses To find O - Law of Conservation of Mass Combustion Analysis Mass Unknown = Mass C + Mass H + Mass O Mass of O is easy to find! Must convert to MOLES to find empirical formula. Use moles of C, H, O to determine empirical formula as before (divide by smallest) Can be tangly, but remember you re just finding the number of moles of each element Combustion Analysis Example Vitamin C (ascorbic acid) is composed of carbon, hydrogen, and oxygen. Combustion of a 3.87 g sample yields 5.80 g of CO 2 and 1.58 g of H 2 O What is the empirical formula of Vitamin C? If the molar mass of Vitamin C is g/mol, what is its molecular formula? 4

5 Dry Stoichiometry For given a reaction, you will be provided with the amount of one substance and asked to find the amount of another Reaction MUST be balanced! Convert given mass of substance into moles Relate moles of what you want to moles of what you have (mole ratio) Convert moles of desired substance back to the required unit (e.g. mass in grams) Dry Stoichiometry Example Given the unbalanced reaction: NaHCO 3(s) Na 2 CO 2(s) + CO 2(s) + H 2 O (l) What mass of sodium carbonate is produced when 4.00 g of sodium bicarbonate is decomposed? Percent Yield Percent Yield Example Normally given as a secondary part of a longer question You will be given the mass of product actually obtained for a particular reaction To find the % yield, divide this value by the calculated (theoretical) mass and multiply by 100% Actual Mass 100% = Percent Yield Theoretical Mass If 2.12 g of sodium carbonate was produced in the previous reaction, what would the percent yield be? NaHCO 3(s) Na 2 CO 2(s) + CO 2(s) + H 2 O (l) 5

6 Limiting Reagent Similar to a regular stoichiometry problem, except you will be given amounts of two or more reactants and asked to determine the amount of product that would be produced May be followed by a percent yield question You must work with ALL reactants to determine how much product each would produce Limiting Reagent To begin, convert all reactant masses into moles (n = m/mm) Determine the amount of product that would result if each reactant was used up completely (multiply by mole ratio comes from BALANCED equation) # mol product moles reactant # mol reactant = moles Product Mole ratio (from coefficients) Limiting Reagent Limiting reagent is the reactant that gives the smallest amount of product This smallest amount of product is the actual amount of product produced (in moles) Use this value to determine the mass (or other desired unit) of product produced Amounts of excess reagents can be determined by subtracting the moles used (mole ratio again!) from initial moles of each excess reactant Limiting Reagent Example Ammonia gas can be prepared as follows: 2NH 4 Cl (s) + CaO (s) 2NH 3(g) + H 2 O (g) + CaCl 2(s) If 112 g of CaO reacts with 224 g of NH 4 Cl, what mass of NH 3 would be produced? What mass of excess reagent will remain after complete reaction? If 38.7 g of NH 3 is obtained, find the % yield 6

7 Titrations Titration Example A known amount of a solution with known concentration is added to a known amount of a second solution, having unknown concentration Identical to other stoichiometry problems, except we now determine moles using concentrations and volumes instead of masses and molar masses A ml aliquot of Ba(OH) 2 solution is titrated with standardized mol/l HBr (aq). At the equivalence point, ml of HBr solution was added. What is the concentration of the Ba(OH) 2 solution? Lewis Structures Lewis Structures Useful for showing valence electrons in atoms, ions, and compounds Use dots, arranged in pairs, to depict valence electrons 7

8 Molecular Lewis Structures Molecular compounds contain two or more non-metals, held together by covalent bonds Electron sharing Lewis structures are constructed a little differently, but in a step-wise manner that is the SAME for all covalent compounds and ions! Drawing Lewis Structures 1. Count total valence electrons for all atoms Groups 1 and 2 have 1 and 2 valence electrons respectively For other main group elements (Grps 13-18), use Group # - 10: Group 14 has 4 valence e - Any ionic charge MUST be accounted for! For negatively charged ions, add a number of electrons corresponding to the charge For positively charged ions, subtract a number of electrons corresponding to the charge Drawing Lewis Structures 2. Determine the central atom typically the least electronegative atom Exceptions: Hydrogen is NEVER the central atom Carbon is ALWAYS the central atom 3. Attach remaining atoms to central atom via single bonds (bonding pairs of electrons) Drawing Lewis Structures 4. Subtract bonding pair electrons from total valence electrons (2 e - per single bond) 5. Assign remaining electrons to terminal atoms, fulfilling octet (8e - total each) 6. Assign any leftover electrons to the central atom (in pairs) Don t forget to indicate overall charge when drawing ions! 8

9 Drawing Lewis Structures Lewis Structure Examples 7. Calculate formal charge for each atom: FC = (valence e - ) (unbonded e - ) (½ bonding e - ) [FC = (valence e - ) (unbonded e - ) (bonds)] 8. Reduce formal charges by making double or triple bonds wherever possible If you have a choice, take e - from the less EN atom 9. Check for resonance structures (more than one possible Lewis Structure) Draw Lewis Structures for the following: Dichloromethane (CH 2 Cl 2 ) Nitrite ion (NO 2- ) Chlorine difluoride cation (ClF 2+ ) Preparation for Final Review old tests, assignments, and tutorial notes. Do the online practice sheets! If you re having trouble with a particular topic get some FREE help with it Chemistry 1010 Help Centre: C-2022 Mon-Thurs, 9am-4:30pm; Fri, 9am-3:30pm Chemistry Resource Room: C-2010 Open Sat, April 13 and Sun, April 14: 10am-6pm A Few Pointers There are many parts of a question, other than the right answer, that are worth marks Show any/all formulas you use Keep track of sig figs! It s good to keep an extra digit or two until the end, but be sure to indicate this! Always give final answers with proper sig figs Show all workings!!! (This includes molar mass) Read and re-read the question make sure you know what exactly is expected/required Show all units, and double check them 9

10 Good Luck on Exams!!! Have a great summer! 10

Chapter 1 The Atomic Nature of Matter: Selected Answersc for Practice Exam.

Chapter 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

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

Chapter 3. Chemical Reactions and Reaction Stoichiometry. Lecture Presentation. James F. Kirby Quinnipiac University Hamden, CT Lecture Presentation Chapter 3 Chemical Reactions and Reaction James F. Kirby Quinnipiac University Hamden, CT The study of the mass relationships in chemistry Based on the Law of Conservation of Mass

More information

Chapter 3: Stoichiometry

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

More information

Other Stoich Calculations A. mole mass (mass mole) calculations. GIVEN mol A x CE mol B. PT g A CE mol A MOLE MASS :

Other 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 information

The Mole Concept. The Mole. Masses of molecules

The Mole Concept. The Mole. Masses of molecules The Mole Concept Ron Robertson r2 c:\files\courses\1110-20\2010 final slides for web\mole concept.docx The Mole The mole is a unit of measurement equal to 6.022 x 10 23 things (to 4 sf) just like there

More information

Calculating Atoms, Ions, or Molecules Using Moles

Calculating Atoms, Ions, or Molecules Using Moles TEKS REVIEW 8B Calculating Atoms, Ions, or Molecules Using Moles TEKS 8B READINESS Use the mole concept to calculate the number of atoms, ions, or molecules in a sample TEKS_TXT of material. Vocabulary

More information

Formulas, Equations and Moles

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

More information

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

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

More information

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

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

More information

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

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

More information

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

1. How many hydrogen atoms are in 1.00 g of hydrogen? MOLES AND CALCULATIONS USING THE MOLE CONCEPT INTRODUCTORY TERMS A. What is an amu? 1.66 x 10-24 g B. We need a conversion to the macroscopic world. 1. How many hydrogen atoms are in 1.00 g of hydrogen?

More information

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

Stoichiometry. What is the atomic mass for carbon? For zinc? Stoichiometry Atomic Mass (atomic weight) Atoms are so small, it is difficult to discuss how much they weigh in grams We use atomic mass units an atomic mass unit (AMU) is one twelfth the mass of the catbon-12

More information

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

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

More information

Unit 2: Quantities in Chemistry

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

More information

Chemistry I: Using Chemical Formulas. Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu.

Chemistry I: Using Chemical Formulas. Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu. Chemistry I: Using Chemical Formulas Formula Mass The sum of the average atomic masses of all elements in the compound. Units are amu. Molar Mass - The mass in grams of 1 mole of a substance. Substance

More information

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

Part One: Mass and Moles of Substance. Molecular Mass = sum of the Atomic Masses in a molecule CHAPTER THREE: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS Part One: Mass and Moles of Substance A. Molecular Mass and Formula Mass. (Section 3.1) 1. Just as we can talk about mass of one atom of

More information

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

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

More information

Chemical Equations & Stoichiometry

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

More information

Molecular Formula: Example

Molecular 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 information

Chapter 3 Calculation with Chemical Formulas and Equations

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

More information

Mole Notes.notebook. October 29, 2014

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

More information

The 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. 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 information

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

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

More information

Chapter 1 The Atomic Nature of Matter

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

More information

Chapter 3: ex. P2O5 molecular mass = 2(30.97 amu) + 5(16.00 amu) = amu

Chapter 3: ex. P2O5 molecular mass = 2(30.97 amu) + 5(16.00 amu) = amu Molecular Mass and Formula Mass for molecular compounds: the molecular mass is the mass (in amu) of one molecule of the compound molecular mass = atomic masses of elements present Chapter 3: ex. P2O5 molecular

More information

Chapter 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 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 information

Chemistry B11 Chapter 4 Chemical reactions

Chemistry 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 information

Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations

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

More information

We 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?

We 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 information

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

IB Chemistry 1 Mole. One atom of C-12 has a mass of 12 amu. One mole of C-12 has a mass of 12 g. Grams we can use more easily. The Mole Atomic mass units and atoms are not convenient units to work with. The concept of the mole was invented. This was the number of atoms of carbon-12 that were needed to make 12 g of carbon. 1 mole

More information

Mass and Moles of a Substance

Mass and Moles of a Substance Chapter Three Calculations with Chemical Formulas and Equations Mass and Moles of a Substance Chemistry requires a method for determining the numbers of molecules in a given mass of a substance. This allows

More information

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

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

More information

Sample Exercise 3.1 Interpreting and Balancing Chemical Equations

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

More information

THE MOLE / COUNTING IN CHEMISTRY

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 information

Chemical calculations

Chemical 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 information

CHEMICAL FORMULA COEFFICIENTS AND SUBSCRIPTS. Chapter 3: Molecular analysis 3O 2 2O 3

CHEMICAL FORMULA COEFFICIENTS AND SUBSCRIPTS. Chapter 3: Molecular analysis 3O 2 2O 3 Chapter 3: Molecular analysis Read: BLB 3.3 3.5 H W : BLB 3:21a, c, e, f, 25, 29, 37,49, 51, 53 Supplemental 3:1 8 CHEMICAL FORMULA Formula that gives the TOTAL number of elements in a molecule or formula

More information

Ionic and Covalent Bonds

Ionic and Covalent Bonds Ionic and Covalent Bonds Ionic Bonds Transfer of Electrons When metals bond with nonmetals, electrons are from the metal to the nonmetal The becomes a cation and the becomes an anion. The between the cation

More information

Element of same atomic number, but different atomic mass o Example: Hydrogen

Element 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 information

Chemical Composition. Introductory Chemistry: A Foundation FOURTH EDITION. Atomic Masses. Atomic Masses. Atomic Masses. Chapter 8

Chemical 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

Sample Exercise 8.1 Magnitudes of Lattice Energies

Sample Exercise 8.1 Magnitudes of Lattice Energies Sample Exercise 8.1 Magnitudes of Lattice Energies Without consulting Table 8.2, arrange the following ionic compounds in order of increasing lattice energy: NaF, CsI, and CaO. Analyze: From the formulas

More information

Chapter 6 Chemical Calculations

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

More information

CP Chemistry Review for Stoichiometry Test

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

More information

Calculations with Chemical Formulas and Equations

Calculations 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 information

The Mole Concept. A. Atomic Masses and Avogadro s Hypothesis

The 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 information

Name Date Class STOICHIOMETRY. SECTION 12.1 THE ARITHMETIC OF EQUATIONS (pages 353 358)

Name 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

Exam 2 Chemistry 65 Summer 2015. Score:

Exam 2 Chemistry 65 Summer 2015. Score: Name: Exam 2 Chemistry 65 Summer 2015 Score: Instructions: Clearly circle the one best answer 1. Valence electrons are electrons located A) in the outermost energy level of an atom. B) in the nucleus of

More information

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

Atomic Masses. Chapter 3. Stoichiometry. Chemical Stoichiometry. Mass and Moles of a Substance. Average Atomic Mass Atomic Masses Chapter 3 Stoichiometry 1 atomic mass unit (amu) = 1/12 of the mass of a 12 C atom so one 12 C atom has a mass of 12 amu (exact number). From mass spectrometry: 13 C/ 12 C = 1.0836129 amu

More information

Ch. 10 The Mole I. Molar Conversions

Ch. 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 information

Stoichiometry Exploring a Student-Friendly Method of Problem Solving

Stoichiometry Exploring a Student-Friendly Method of Problem Solving Stoichiometry Exploring a Student-Friendly Method of Problem Solving Stoichiometry comes in two forms: composition and reaction. If the relationship in question is between the quantities of each element

More information

Moles and Chemical Reactions. Moles and Chemical Reactions. Molar mass = 2 x 12.011 + 6 x 1.008 + 1 x15.999 = 46.069 g/mol

Moles and Chemical Reactions. Moles and Chemical Reactions. Molar mass = 2 x 12.011 + 6 x 1.008 + 1 x15.999 = 46.069 g/mol We have used the mole concept to calculate mass relationships in chemical formulas Molar mass of ethanol (C 2 H 5 OH)? Molar mass = 2 x 12.011 + 6 x 1.008 + 1 x15.999 = 46.069 g/mol Mass percentage of

More information

Stoichiometry. Lecture Examples Answer Key

Stoichiometry. 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 information

7-5.5. Translate chemical symbols and the chemical formulas of common substances to show the component parts of the substances including:

7-5.5. Translate chemical symbols and the chemical formulas of common substances to show the component parts of the substances including: 7-5.5 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 information

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

Chemical Calculations: The Mole Concept and Chemical Formulas. AW Atomic weight (mass of the atom of an element) was determined by relative weights. 1 Introduction to Chemistry Atomic Weights (Definitions) Chemical Calculations: The Mole Concept and Chemical Formulas AW Atomic weight (mass of the atom of an element) was determined by relative weights.

More information

Chemical Calculations: Formula Masses, Moles, and Chemical Equations

Chemical Calculations: Formula Masses, Moles, and Chemical Equations Chemical Calculations: Formula Masses, Moles, and Chemical Equations Atomic Mass & Formula Mass Recall from Chapter Three that the average mass of an atom of a given element can be found on the periodic

More information

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

Chemical Reactions. Chemical Equations. Mole as Conversion Factor: To convert between number of particles and an equivalent number of moles: Quantities of Reactants and Products CHAPTER 3 Chemical Reactions Stoichiometry Application of The Law of Conservation of Matter Chemical book-keeping Chemical Equations Chemical equations: Describe proportions

More information

The Mole and Molar Mass

The 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 information

Chemical Reactions. Chemistry 100. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 4

Chemical Reactions. Chemistry 100. Bettelheim, Brown, Campbell & Farrell. Introduction to General, Organic and Biochemistry Chapter 4 Chemistry 100 Bettelheim, Brown, Campbell & Farrell Ninth Edition Introduction to General, Organic and Biochemistry Chapter 4 Chemical Reactions Chemical Reactions In a chemical reaction, one set of chemical

More information

The Mole. 6.022 x 10 23

The 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 information

Is it still balanced? Has anything changed? What does it mean? Is it still balanced? Has anything changed? What does it mean?

Is it still balanced? Has anything changed? What does it mean? Is it still balanced? Has anything changed? What does it mean? Chemistry 11 Unit VII Stoichiometry Introduction: Let s look at the following equation 2 H 2 + O 2 2 H 2 O The numbers in front of the H 2 and H 2 O are called coefficients. What do they tell us? They

More information

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

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

More information

Formulae, stoichiometry and the mole concept

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

More information

Chapter 3. Molecules, Compounds, and Chemical Composition

Chapter 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 information

Return to Lab Menu. Stoichiometry Exploring the Reaction between Baking Soda and Vinegar

Return to Lab Menu. Stoichiometry Exploring the Reaction between Baking Soda and Vinegar Return to Lab Menu Stoichiometry Exploring the Reaction between Baking Soda and Vinegar Objectives -to observe and measure mass loss in a gas forming reaction -to calculate CO 2 loss and correlate to a

More information

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

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

More information

Lecture 5, The Mole. What is a mole?

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

More information

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

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

More information

Chapter 3 Stoichiometry

Chapter 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 information

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

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

More information

Introduction to Chemistry

Introduction to Chemistry 1 Copyright ç 1996 Richard Hochstim. All rights reserved. Terms of use. Introduction to Chemistry In Chemistry the word weight is commonly used in place of the more proper term mass. 1.1 Atoms, Ions, and

More information

MASS RELATIONSHIPS IN CHEMICAL REACTIONS

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

More information

Calculations with Chemical Reactions

Calculations with Chemical Reactions Calculations with Chemical Reactions Calculations with chemical reactions require some background knowledge in basic chemistry concepts. Please, see the definitions from chemistry listed below: Atomic

More information

The Empirical Formula of a Compound

The 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 information

11-1 Stoichiometry. Represents

11-1 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 information

Chapter 3. Mass Relationships in Chemical Reactions

Chapter 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 information

Lecture Notes Chemistry E-1. Chapter 3

Lecture Notes Chemistry E-1. Chapter 3 Lecture Notes Chemistry E-1 Chapter 3 http://inserbia.info/news/wp-content/uploads/2013/05/tamiflu.jpg http://nutsforhealthcare.files.wordpress.com/2013/01/tamiflu-moa.jpg The Mole A mole is a certain

More information

Test 8: Review Questions

Test 8: Review Questions Name: Thursday, February 14, 2008 Test 8: Review Questions 1. Based on bond type, which compound has the highest melting point? 1. CH OH 3. CaCl 3 2 2. C H 4. CCl 6 14 4 2. Which compound contains ionic

More information

Simple vs. True. Simple vs. True. Calculating Empirical and Molecular Formulas

Simple vs. True. Simple vs. True. Calculating Empirical and Molecular Formulas Calculating Empirical and Molecular Formulas Formula writing is a key component for success in chemistry. How do scientists really know what the true formula for a compound might be? In this lesson we

More information

Chemistry Stoichiometry Lesson 8 Lesson Plan David V. Fansler

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

More information

IB Chemistry. DP Chemistry Review

IB 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 information

file:///biology Exploring Life/BiologyExploringLife04/

file:///biology Exploring Life/BiologyExploringLife04/ Objectives Compare and contrast ionic bonds and covalent bonds. Describe various ways to represent molecules. Summarize what happens in a chemical reaction. Key Terms ionic bond ion covalent bond molecule

More information

EXPERIMENT 12: Empirical Formula of a Compound

EXPERIMENT 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 information

General Chemistry I (FC, 09-10) Lab #3: The Empirical Formula of a Compound. Introduction

General 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 information

0.786 mol carbon dioxide to grams g lithium carbonate to mol

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

More information

MOLECULAR MASS AND FORMULA MASS

MOLECULAR 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 information

Module Three Characterizing Compounds Using Mass Percents and Empirical Formulas. Chem 170. Stoichiometric Calculations.

Module 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 information

How much does a single atom weigh? Different elements weigh different amounts related to what makes them unique.

How much does a single atom weigh? Different elements weigh different amounts related to what makes them unique. How much does a single atom weigh? Different elements weigh different amounts related to what makes them unique. What units do we use to define the weight of an atom? amu units of atomic weight. (atomic

More information

Chapter 10 Chemical Quantities

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

More information

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

Concept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects. Chapter 3. Stoichiometry: Mole-Mass Relationships in Chemical Reactions Concept 1. The meaning and usefulness of the mole The mole (or mol) represents a certain number of objects. SI def.: the amount of

More information

Moles. Moles. Moles. Moles. Balancing Eqns. Balancing. Balancing Eqns. Symbols Yields or Produces. Like a recipe:

Moles. 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 information

Simple vs. True Calculating Empirical and Molecular Formulas

Simple vs. True Calculating Empirical and Molecular Formulas 17 Calculating Empirical and Molecular Formulas OBJECTIVE Students will learn to calculate empirical and molecular formulas and practice applying logical problemsolving skills. LEVEL Chemistry NATIONAL

More information

Chapter 6 Notes. Chemical Composition

Chapter 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 information

10 The Mole. Section 10.1 Measuring Matter

10 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 information

Stoichiometry and Aqueous Reactions (Chapter 4)

Stoichiometry and Aqueous Reactions (Chapter 4) Stoichiometry and Aqueous Reactions (Chapter 4) Chemical Equations 1. Balancing Chemical Equations (from Chapter 3) Adjust coefficients to get equal numbers of each kind of element on both sides of arrow.

More information

1. 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) 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 information

Chapter 3: STOICHIOMETRY: MASS, FORMULAS, AND REACTIONS

Chapter 3: STOICHIOMETRY: MASS, FORMULAS, AND REACTIONS Chapter 3: STOICHIOMETRY: MASS, FORMULAS, AND REACTIONS Problems: 3.1-3.8, 3.11, 3.14-3.90, 3.103-3.120, 3.122-3.125, 3.128-3.131, 3.134, 3.137-36.138, 3.140-3.142 3.2 THE MOLE Stoichiometry (STOY-key-OM-e-tree):

More information

Stoichiometry. Unit Outline

Stoichiometry. 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 information

Balancing Chemical Equations

Balancing 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 information

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

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

More information

Chemistry Final Study Guide

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

More information

Unit 6 The Mole Concept

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

More information