# Mole - Mass Relationships in Chemical Systems

Save this PDF as:

Size: px
Start display at page:

## Transcription

1 Chapter 3: Stoichiometry Mole - Mass Relationships in Chemical Systems 3.1 The Mole 3.2 Determining the Formula of an Unknown Compound 3.3 Writing and Balancing Chemical Equations 3.4 Calculating the Amounts of Reactant and Product 3.5 Fundamentals of Solution Stoichiometry 3-3 Page 1 of 27

2 Mole Concept 1 mole = x = Avogadro s number convenient in measuring the amounts of reactants & products in chemical reactions 1 mole of a substance = Examples: Atomic Mass in grams of an element or Molecular Mass in grams of a compound Mg + S > MgS atoms: > formula units moles: > atoms: > formula units mass: > Page 2 of 27

3 2 Mg + O > 2 MgO atoms: > formula units moles: > > formula units mass: > Stoichiometric Equivalencies Ratio in which the elements occur in a compound e.g. Al 2 O 3 2 Al 3+ : 3 O 2-2 mol Al 3+ : 3 mol O 2-2 mol Al : 3 mol O 54.0 g Al : 48.0 g O Sample Problems: 1. How many moles of Al are needed to react with 2.7 mol oxygen atoms to make Al 2 O 3? 2. How many moles of Al are needed to make 3.0 mol Al 2 O 3? Ans. = 1.8 mol Al Ans. = 4.5 mol Al Page 3 of 27

4 3. How many moles of oxygen atoms are needed to make 3.0 mol Al 2 O 3? Ans. = 9.0 mol O atoms 4. How many moles of oxygen molecules are needed to make 3.0 mol Al 2 O 3? Ans. = 4.5 mol O 2 molecules Measuring Moles of Elements and Compounds Atomic Mass or Molecular Mass in grams (Molar Mass): o Contains 1 mole (Avogadro s number) of atoms or molecules Some Examples: SUBSTANCE MOLAR MASS (g/mol) Au O O H 2 O Ca(OH) CaCl. 2 2H 2 O Page 4 of 27

5 Mass <-----> Mole conversions Use molar mass as conversion factor Examples: 1. How many moles of gold are in g Au? 2. How many moles of water are in 72.0 g water? 3. How many moles of oxygen molecules are in 16.0 g oxygen? 4. How many grams of water are in 3.5 mol water? 5. How many grams of gold are in 1.97 x atoms of gold? 6. How can you determine the mass of one water molecule? Answers: mole Au; mol H2O; mol O2; g H2O; x g Au Applications of Stoichiometry 1. How many grams of chlorine atoms are needed to combine with 24.4 g silicon to produce silicon tetrachloride? Answer: 123 g Cl a. How many chlorine atoms are needed? b. How many chlorine molecules are needed? Ans x Cl atoms Ans x Cl 2 molecules Page 5 of 27

6 Percentage Composition Mass % of each element in the compound: Examples % by mass of = [mass of element / mass of sample] * 100 element Intensive property Used in determining the formulas of new compounds g Fe react with oxygen gas to yield 7.98 g iron oxide. Calculate the % composition of the product and then determine if the product is iron (II) oxide or iron (III) oxide. 2. Which oxide of nitrogen has a % composition of 25.94% N and 74.06% O, N 2 O, NO, N 2 O 3, N 2 O 4, or N 2 O 5? Empirical and Molecular formulas Empirical Formula Smallest whole number ratio of atoms in the compound that agrees with the elemental analysis of the compound Molecular Formula True formula of a compound as it exists in nature A multiple of the empirical formula Remember... The formula of compound represents the mole ratio of the elements present in the compound Table 3.3 Page 6 of 27

7 Some Compounds with Empirical Formula CH 2 O (Composition by Mass 40.0% C, 6.71% H, 53.3%O) Molecular M Formula (g/mol) Name Use or Function CH 2 O Formaldehyde Disinfectant; Biological preservative C 2 H 4 O Acetic acid Acetate polymers; vinegar ( 5% solution) C 3 H 6 O Lactic acid Causes milk to sour; forms in muscle during exercise C 4 H 8 O Erythrose Forms during sugar metabolism C 5 H 10 O Ribose Component of many nucleic acids and vitamin B 2 C 6 H 12 O Glucose Major nutrient for energy in cells Page 7 of 27

8 Examples Calculate the empirical formula of magnesium oxide if g Mg react with oxygen to yield g of product. 2. Determine the empirical formula of a compound that is 25.94% Nitrogen and 74.06% Oxygen. Empirical Formulas from % Composition: Assume you have 100 g of the compound!!!! Why??? Steps to Determine Empirical Formulas Mass (g) of Element M (g/mol ) Moles of Element use no. of moles as subscripts Preliminary Formula change to integer subscripts Empirical Formula Page 8 of 27

9 Empirical Formula Determination by Combustion Analysis Figure 3.4 Combustion Train for the Determination of the Chemical Composition of Organic Compounds Where does each of the mfollowing come from? m C n H m + (n+ ) O 2 = n CO(g) + 1. Carbon in the Carbon 2 in the CO 2? 2 2. Hydrogen in the H 2 O? 3. Oxygen in the CO 2? 4. Oxygen in the H 2 O? H 2 O(g) Page 9 of 27

10 Sample Problem 3.6 Determining a Molecular Formula from Combustion Analysis PROBLEM: PLAN: Vitamin C (M=176.12g/mol) is a compound of C,H, and O found in many natural sources especially citrus fruits. When a g sample of vitamin C is placed in a combustion chamber and burned, the following data are obtained: mass of CO 2 absorber after combustion mass of CO 2 absorber before combustion mass of H 2 O absorber after combustion mass of H 2 O absorber before combustion What is the molecular formula of vitamin C? difference (after-before) = mass of oxidized element =85.35g =83.85g =37.96g =37.55g find the mass of each element in its combustion product find the mols preliminary formula empirical formula molecular formula 3-20 Page 10 of 27

11 Sample Problem 3.6 continued Determining a Molecular Formula from Combustion Analysis SOLUTION: CO g-83.85g = 1.50g H 2 O 37.96g-37.55g = 0.41g There are 12.01g C per mol CO g CO g CO g CO 2 = 0.409g C There are 2.016g H per mol H 2 O. 0.41g H 2 O 2.016g H 2 O 18.02g H 2 O O must be the difference: 1.000g - ( ) = = 0.046g H 0.409g C 12.01g C = mol C 0.046g H = mol H 0.545g O = mol O 1.008g H 16.00g O C 1 H 1.3 O 1 C 3 H 4 O g/mol 88.06g = C 6 H 8 O Page 11 of 27

12 Determining the Molecular Formula of a Compound Stuff Needed: o Empirical formula of the compound o Molecular mass of the compound Remember... o The molecular formula is a multiple of the empirical formula. Therefore... o The molecular formula mass is a multiple of the empirical formula mass. Examples The empirical formula of a sugar is CH 2 O. Determine the molecular formula if the molecular mass is g/mol. 2. Explain how you could determine the empirical and molecular formulas of a compound that contains the elements Hg, C, H, and O from the following data. A compound of mercury with a formula mass of 519 g/mol has the following % composition by mass: 77.26% Hg, 9.25% C, 1.17% H, and the balance consisting of Oxygen. Page 12 of 27

13 Writing and Balancing Chemical Equations What do Chemical Equations Show? o Mole ratios of reactants and products o States of reactants and products: (s), (l), (g), (aq) o Energetics Balancing Chemical Equations: trial and error method 1. Write correct formulas for reactants and products 2. Adjust coefficients to get equal numbers of each type of atom on each side of the equation Fe 2 O 3 (s) + C (s) Fe (s) + CO 2 (g) C 4 H 10 (g) + O 2 (g) AgNO 3 (aq) + CaCl 2 (aq) AgCl (s) + NaNO 3 (aq) NaHCO 3 (aq) + H 2 SO 4 (aq) Na 2 SO 4 (aq) + H 2 O (l) + CO 2 (g) Some reactions are nearly impossible to balance by trial and error. E.g. Redox reactions will be covered next chapter! Page 13 of 27

14 Using Chemical Equations in Calculations Recall: Coefficients in Balanced Chemical Reactions give the Mole Ratios between all Reactants and Products!!! e.g. Rusting of Iron: Fe (s) + O 2 (g) Fe 2 O 3 (s) 1. If 2 moles of iron react, how many moles of... a. oxygen will react? b. rust will form? 2. If 27.9 grams of iron rust completely, how many... a. Moles of oxygen will react? b. Molecules of oxygen reat? c. Grams of oxygen? d. Moles of rust will form? e. Grams of rust? Fe = g/mol; O = g/mol; Fe 2 O 3 = g/mol 3. How many kg of gasoline must react to produce 100. lbs of carbon dioxide? Assume that gasoline contains only octane, C 8 H 18 and that carbon dioxide and water are the only two products. Page 14 of 27

15 Fig. 3.8 Page 15 of 27

16 Limiting Reactant Problems Limiting Reactant: Reactant that is consumed completely Limits or determines the amount of product produced The reactant that produces the least amount of product is the limiting reactant An Ice Cream Sundae Analogy for Limiting Reactions 6 scoops of ice cream Fig Page 16 of 27

17 How do you know if a problem is a limiting Reactant Problem??? e.g g Zinc and 32.0 g sulfur reacted to form zinc sulfide: 32.0 g 32.0 g?? g Zn + S ZnS a. Which chemical is the limiting reactant? b. How many grams of ZnS can be formed? c. How many grams of excess reactant will be left after the reaction? e.g. O.360 mol phosphorus pentachloride was slowly added to 2.88 mole of water mol 2.88 mol PCl H 2 O H 3 PO HCl a. Which reactant, if either, is the limiting reactant? b. Calculate the theoretical yields in moles of each product. Page 17 of 27

18 Theoretical Yield and % Yield Problems Theoretical Yield: Yield (amount of product) obtained if all of the limiting reactant is converted to product and none product is lost Yields are almost never 100%. Why? - Incomplete reaction (e.g. Chemical Equilibrium) - Product may be slightly soluble - Product may be volatile - Competing reactions occur - Product sticks to container % Yield = Actual Yield Theoretical Yield x100 Question 3.81 (Page 126 Silberberg 3ed) What is the % yield of a reaction in which 41.5 g tungsten (VI) oxide, W0 3, reacts with excess hydrogen gas to produce metallic tungsten and 9.50 ml water. d water = g/ml, H 2 O = 18.0 g/mol, W = g/mol, W0 3 = g/mol Ans. 98.1% W0 3 (s) + 2 H 2 (g) W (s) + 2 H 2 O (l) Question 3.83 (Page 126 Silberberg 3ed) When 153 g methane and 43.0 g chlorine gas undergo a reaction that has an 80.0% yield, what mass of chloromethane, CH 3 Cl, forms? Hydrogen chloride gas is also produced. CH 4 (g) + Cl 2 (g) CH 3 Cl (g) + HCl (g) 16.0 g/mol g/mol g/mol g/mol Ans: 24.5 g CH 3 Cl Page 18 of 27

19 Solution Stoichiometry Concentration of solutions moles solute Molarity = = Liters of Solution moles L Solute substance dissolved in the solvent usually water Solution: solute and solvent Preparing a Solution Prepare a solution of Sodium Phosphate by dissolving 3.95g of Sodium Phosphate into water and diluting it to ml or l! What is the Molarity of the salt and each of the ions? Na 3 PO 4 (s) + H 2 O (solvent) = 3 Na + (aq) + PO 4-3 (aq) Page 19 of 27

20 Preparing a Solution - II Mol wt of Na 3 PO 4 = g / mol 3.95 g / g/mol = mol Na 3 PO 4 dissolve and dilute to ml M = mol Na 3 PO 4 / l = M Na 3 PO 4 for PO -3 4 ions = M forna + ions = 3 x M = M Page 20 of 27

21 Make a Solution of Potassium Permanganate Problem: What is the molarity of a solution that is prepared a solution by dissolving 1.58 grams of KMnO 4 into sufficient water to make ml of solution? What is the concentration of each ion is the solution? KMnO 4 = g / mole 1.58 g KMnO 4 x 1 mole KMnO 4 = moles KMnO g KMnO 4 4 Molarity = moles KMnO liters = M Molarity of K + ion = [K + ] ion = [MnO 4- ] ion = M Page 21 of 27

22 Dilution of Solutions Take ml of the M KMnO 4 Dilute the ml to Liter. What is the resulting Molarity of the diluted solution? # moles = Volx M L x M = Moles Mol / L = M Another example Preparation of a less concentrated from a more concentrated solution e.g. How would you prepare 500. ml of 0.10 M HCl from a stock solution of concentrated reagent, 12 M HCl? V dil. M dil = V conc. M conc Would you add the acid to the water or the water to the the acid? Answer: 4.2 ml 12M HCl is needed Page 22 of 27

23 Fig Page 23 of 27

24 Calculating Mass of Solute from a Given Volume of Solution Volume (L) of Solution Molarity = M = (mol solute / Liters of solution) = mol/l Moles of Solute Molar Mass (M) = ( mass / mole) = g/mol Mass (g) of Solute Page 24 of 27

25 Calculating Amounts of Reactants and Products for a Reaction in Solution Al(OH) 3 (s) + 3 HCl (aq) 3 H 2 O (l) + AlCl 3 (aq) Mass (g) of Al(OH) 3 Moles of Al(OH) 3 Moles of HCl M (g/mol) molar ratio M ( mol/l) Volume (L) of HCl Given 10.0 g Al(OH) 3, what volume of 1.50 M HCl is required to neutralize the base? Vol HCl = 10.0 g Al(OH) 3 = mol Al(OH) g/mol mol Al(OH) 3 x 3 moles HCl = moles Al(OH) Moles HCl 1.00 L HCl 1.50 Moles HCl x Moles HCl Vol HCl = L = 256 ml HCl Page 25 of 27

26 Acid-Base Problems 1. What volume in ml of O.200 M HCl is needed to neutralize ml of M NaOH? Answer: 50.0 ml M HCl Sample Problem 3.15 Calculating Amounts of Reactants and Products for a Reaction in Solution PROBLEM: Specialized cells in the stomach release HCl to aid digestion. If they release too much, the excess can be neutralized with antacids. A common antacid contains magnesium hydroxide, which reacts with the acid to form water and magnesium chloride solution. As a government chemist testing commercial antacids, you use 0.10M HCl to simulate the acid concentration in the stomach. How many liters of stomach acid react with a tablet containing 0.10g of magnesium hydroxide? PLAN: Write a balanced equation for the reaction; find the grams of Mg(OH) 2 ; determine the mol ratio of reactants and products; use mols to convert to molarity. mass Mg(OH) 2 divide by M mol Mg(OH) 2 L HCl mol HCl divide by M 3-19 mol ratio Page 26 of 27

27 Sample Problem 3.15 continued Calculating Amounts of Reactants and Products for a Reaction in Solution SOLUTION: Mg(OH) 2 (s) + 2HCl(aq) MgCl 2 (aq) + 2H 2 O(l) 0.10g Mg(OH) 2 mol Mg(OH) g Mg(OH) 2 = 1.7x10-3 mol Mg(OH) 2 1.7x10-3 mol Mg(OH) 2 2 mol HCl 1 mol Mg(OH) 2 = 3.4x10-3 mol HCl 3.4x10-3 mol HCl 1L 0.10mol HCl = 3.4x10-2 L HCl 3-20 Page 27 of 27

### 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

### 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

### 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

### Atomic mass is the mass of an atom in atomic mass units (amu)

Micro World atoms & molecules Laboratory scale measurements Atomic mass is the mass of an atom in atomic mass units (amu) By definition: 1 atom 12 C weighs 12 amu On this scale 1 H = 1.008 amu 16 O = 16.00

### 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

### Stoichiometry Review

Stoichiometry Review There are 20 problems in this review set. Answers, including problem set-up, can be found in the second half of this document. 1. N 2 (g) + 3H 2 (g) --------> 2NH 3 (g) a. nitrogen

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

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

### 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 +

### 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

### 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

### 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

### 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

### Chapter 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

### 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

### Chapter 3 Mass Relationships in Chemical Reactions

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

### Tutorial 4 SOLUTION STOICHIOMETRY. Solution stoichiometry calculations involve chemical reactions taking place in solution.

T-27 Tutorial 4 SOLUTION STOICHIOMETRY Solution stoichiometry calculations involve chemical reactions taking place in solution. Of the various methods of expressing solution concentration the most convenient

### W1 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

### 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

### 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

### 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

### 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

### 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

### 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

### 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

### Calculation 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

### 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

### 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

### 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

### Name Class Date. Section: Calculating Quantities in Reactions. Complete each statement below by writing the correct term or phrase.

Skills Worksheet Concept Review Section: Calculating Quantities in Reactions Complete each statement below by writing the correct term or phrase. 1. All stoichiometric calculations involving equations

### Chapter 6 Oxidation-Reduction Reactions. Section 6.1 2. Which one of the statements below is true concerning an oxidation-reduction reaction?

Chapter 6 Oxidation-Reduction 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

### Answers and Solutions to Text Problems

Chapter 7 Answers and Solutions 7 Answers and Solutions to Text Problems 7.1 A mole is the amount of a substance that contains 6.02 x 10 23 items. For example, one mole of water contains 6.02 10 23 molecules

### Appendix D. Reaction Stoichiometry D.1 INTRODUCTION

Appendix D Reaction Stoichiometry D.1 INTRODUCTION In Appendix A, the stoichiometry of elements and compounds was presented. There, the relationships among grams, moles and number of atoms and molecules

### 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

### Unit 10A Stoichiometry Notes

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

### Reactions. Balancing Chemical Equations uses Law of conservation of mass: matter cannot be lost in any chemical reaction

Reactions Chapter 8 Combustion Decomposition Combination Chapter 9 Aqueous Reactions Exchange reactions (Metathesis) Formation of a precipitate Formation of a gas Formation of a week or nonelectrolyte

### 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)

### 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

### 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

### CHEMICAL REACTIONS. Chemistry 51 Chapter 6

CHEMICAL REACTIONS A chemical reaction is a rearrangement of atoms in which some of the original bonds are broken and new bonds are formed to give different chemical structures. In a chemical reaction,

### BALANCING 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

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

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

### CHEMICAL 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

### 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

### 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,

### 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

### 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,

### 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

### CHAPTER 9. ANS: a. ANS: d. ANS: c. ANS: a. ANS: c

CHAPTER 9 1. Which one of the following is the acid in vinegar? a. acetic acid b. citric acid c. muriatic acid d. ascorbic acid 2. Which is a basic or alkaline substance? a. gastric fluid b. black coffee

### 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

### 1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams?

Name: Tuesday, May 20, 2008 1. What is the molecular formula of a compound with the empirical formula PO and a gram-molecular mass of 284 grams? 2 5 1. P2O 5 3. P10O4 2. P5O 2 4. P4O10 2. Which substance

### Chapter 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

### 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.

### 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

### Writing 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

### 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)

### 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

### Potassium + Chlorine. K(s) + Cl 2 (g) 2 KCl(s)

Types of Reactions Consider for a moment the number of possible chemical reactions. Because there are millions of chemical compounds, it is logical to expect that there are millions of possible chemical

### Molar 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

### The Mole Concept. Chapter 3 Stoichiometry: Mass, Formulas, and Reactions. Chapter 3: Stoichiometry. The Mole Concept. Counting By Weighing.

Chapter 3 Stoichiometry: Mass, Formulas, and Reactions Chapter Objectives: Learn how to use the atomic mass of an element and the molecular weight of a compound to relate grams, moles, and the number of

### Ex: 1. 1 mol C H O g C H O. Ex: mol C H O mol C H O.

Example of how to solve a mass-to-mass stoichiometry problem Example Problem: If 1.00 gram of the simple sugar fructose (C 6 H 12 O 6 ) is burned in atmospheric oxygen of (O 2 ), what mass of carbon dioxide

### 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

### Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry

AP Chemistry A. Allan Chapter 4 Notes - Types of Chemical Reactions and Solution Chemistry 4.1 Water, the Common Solvent A. Structure of water 1. Oxygen's electronegativity is high (3.5) and hydrogen's

### 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

### Lecture Topics Atomic weight, Mole, Molecular Mass, Derivation of Formulas, Percent Composition

Mole Calculations Chemical Equations and Stoichiometry Lecture Topics Atomic weight, Mole, Molecular Mass, Derivation of Formulas, Percent Composition Chemical Equations and Problems Based on Miscellaneous

### 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

### 1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436 #1, 7, 8, 11

SCH3U- R.H.KING ACADEMY SOLUTION & ACID/BASE WORKSHEET Name: The importance of water - MAKING CONNECTION READING 1. Read P. 368-375, P. 382-387 & P. 429-436; P. 375 # 1-11 & P. 389 # 1,7,9,12,15; P. 436

### Chapter 7: Chemical Equations. Name: Date: Period:

Chapter 7: Chemical Equations Name: Date: Period: 7-1 What is a chemical reaction? Read pages 232-237 a) Explain what a chemical reaction is. b) Distinguish between evidence that suggests a chemical reaction

### 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

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

CHEMISTRY 123-07 Midterm #1 Answer key October 14, 2010 Statistics: Average: 74 p (74%); Highest: 97 p (95%); Lowest: 33 p (33%) Number of students performing at or above average: 67 (57%) Number of students

### 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

### UNIT (4) CALCULATIONS AND CHEMICAL REACTIONS

UNIT (4) CALCULATIONS AND CHEMICAL REACTIONS 4.1 Formula Masses Recall that the decimal number written under the symbol of the element in the periodic table is the atomic mass of the element. 1 7 8 12

### Unit 9 Stoichiometry Notes (The Mole Continues)

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

### Chemical Reactions in Water Ron Robertson

Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Properties of Compounds in Water Electrolytes and nonelectrolytes Water soluble compounds

### Chemical Reactions in Water

Chemical Reactions in Water Ron Robertson r2 f:\files\courses\1110-20\2010 possible slides for web\waterchemtrans.doc Acids, Bases and Salts Acids dissolve in water to give H + ions. These ions attach

### Problem Solving. Stoichiometry of Gases

Skills Worksheet Problem Solving Stoichiometry of Gases Now that you have worked with relationships among moles, mass, and volumes of gases, you can easily put these to work in stoichiometry calculations.

### Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent

Solution a homogeneous mixture = A solvent + solute(s) Aqueous solution water is the solvent Water a polar solvent: dissolves most ionic compounds as well as many molecular compounds Aqueous solution:

### Chemistry 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

### Chapter 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

### 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

### Liquid 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

### 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.

### 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

### 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.

### 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

### HOMEWORK 4A. Definitions. Oxidation-Reduction Reactions. Questions

HOMEWORK 4A Oxidation-Reduction Reactions 1. Indicate whether a reaction will occur or not in each of following. Wtiring a balcnced equation is not necessary. (a) Magnesium metal is added to hydrochloric

### Chapter 3 Molecules, Moles, and Chemical Equations. Chapter Objectives. Warning!! Chapter Objectives. Chapter Objectives

Larry Brown Tom Holme www.cengage.com/chemistry/brown Chapter 3 Molecules, Moles, and Chemical Equations Jacqueline Bennett SUNY Oneonta 2 Warning!! These slides contains visual aids for learning BUT they

### Name: Class: Date: 2 4 (aq)

Name: Class: Date: Unit 4 Practice Test Multiple Choice Identify the choice that best completes the statement or answers the question. 1) The balanced molecular equation for complete neutralization of

### 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

### Aqueous Solutions. Water is the dissolving medium, or solvent. Some Properties of Water. A Solute. Types of Chemical Reactions.

Aqueous Solutions and Solution Stoichiometry Water is the dissolving medium, or solvent. Some Properties of Water Water is bent or V-shaped. The O-H bonds are covalent. Water is a polar molecule. Hydration

### ATOMS. 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)

### 4.1 Stoichiometry. 3 Basic Steps. 4. Stoichiometry. Stoichiometry. Butane Lighter 2C 4 H 10 + 13O 2 10H 2 O + 8CO 2

4. Stoichiometry 1. Stoichiometric Equations 2. Limiting Reagent Problems 3. Percent Yield 4. Limiting Reagent Problems 5. Concentrations of Solutes 6. Solution Stoichiometry 7. ph and Acid Base Titrations

### Chapter 5. Chemical Reactions and Equations. Introduction. Chapter 5 Topics. 5.1 What is a Chemical Reaction

Introduction Chapter 5 Chemical Reactions and Equations Chemical reactions occur all around us. How do we make sense of these changes? What patterns can we find? 1 2 Copyright The McGraw-Hill Companies,

### Stoichiometry. 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

### GHW#9. Louisiana Tech University, Chemistry 100. POGIL Exercise on Chapter 4. Quantities of Reactants and Products: Equations, Patterns and Balancing

GHW#9. Louisiana Tech University, Chemistry 100. POGIL Exercise on Chapter 4. Quantities of Reactants and Products: Equations, Patterns and Balancing Why? In chemistry, chemical equations represent changes

### The component present in larger proportion is known as solvent.

40 Engineering Chemistry and Environmental Studies 2 SOLUTIONS 2. DEFINITION OF SOLUTION, SOLVENT AND SOLUTE When a small amount of sugar (solute) is mixed with water, sugar uniformally dissolves in water

### CHM-101-A Exam 2 Version 1 October 10, 2006

CHM-101-A 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.

### Chemical Quantities and Aqueous Reactions

4 Chemical Quantities and Aqueous Reactions I feel sorry for people who don t understand anything about chemistry. They are missing an important source of happiness. Linus Pauling (1901 1994) 4.1 Climate

### Name: Teacher: Pd. Date:

Name: Teacher: Pd. Date: STAAR Tutorial : Energy and Matter: Elements, Compounds, and Chemical Equations: 6.5C Differentiate between elements and compounds on the most basic level. 8.5F Recognize whether

### 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.

### Solutions CHAPTER Specific answers depend on student choices.

CHAPTER 15 1. Specific answers depend on student choices.. A heterogeneous mixture does not have a uniform composition: the composition varies in different places within the mixture. Examples of non homogeneous