Introductory Chemistry, 3 rd Edition Nivaldo Tro. Roy Kennedy Massachusetts Bay Community College Wellesley Hills, Maqqwertd ygoijpk[l

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Introductory Chemistry, 3 rd Edition Nivaldo Tro. Roy Kennedy Massachusetts Bay Community College Wellesley Hills, Maqqwertd ygoijpk[l"

Transcription

1 Introductory Chemistry, 3 rd Edition Nivaldo Tro Quantities in Car an octane and oxygen molecules and carbon dioxide and water Chemical Reactions Roy Kennedy Massachusetts Bay Community College Wellesley Hills, Maqqwertd ygoijpk[l 2009, Prentice? Hall

2 Outline 8.1 Global Warming : Too much Carbon Dioxide 8.2 Making Pancakes: Relationships between Ingredients 8.3 Making Molecules: Mole to Mole Conversions 8.4 Making Molecule: Mass to Mass Conversions 8.5 More Pancakes: Limiting Reactant, Theoretical Yield, and Percent Yield 8.6 Limiting Reactant, Theoretical Yield, and Percent Yield form Initial Reactants 8.7 Enthalpy: Measure of the Heat Evolved or Absorbed during a Chemical Reaction 2

3 8.1 Global Warming : Too much Carbon Dioxide 3

4 Burning of Fossil Car and molecules from chapter opening Fuels Internal combustion engines produe Carbon dioxide by burning fuels. For example octane, C 8 H 18, in gasoline. 2C 8 H 18 (l) + 25O 2 (g) 16 CO 2 (g) + 18H 2 O(g)

5 Global Warming Average 0.6 C rise in atmospheric temperature since In the same period atmospheric CO 2 levels have risen 25%. Are the two related? Figure 8.1 and Figure 8.2 Showing global tempertature Rise and greenhouse effect. 5

6 Increased CO 2 The primary source of the increased CO 2 levels is combustion of fossil fuels 1860 = Industrial Revolution in the U.S. and Europe. Methane in natural gas CH4(g) 2 O2(g) CO2(g) 2 H2O(g) 6

7 Quantities in Chemical Reactions All substances in a chemical reaction are related. The numerical relationships between compounds in a chemical reaction is called stoichiometry. 7

8 8.2 Making Pancakes: Relationships between Ingredients 8

9 Making Pancakes Pancakes are made with specific amounts of ingredients. Your book forgot buttermilk! Pancake recipe figure on page cup flour + 2 eggs + ½ tsp baking powder +3/4 cup buttermilk 5 pancakes 9

10 Making Pancakes, Continued You can scale the recipe up of down. Notice that for every 2 eggs 5 pancakes What if you have 8 eggs? pancakes 5 pancakes 8 eggs 2 eggs 20 pancakes Graphics illustrating the above equation 10

11 8.2 Making Pancakes: Relationships between Ingredients 11

12 Making Molecules Mole-to-Mole Conversions The balanced equation = chemical recipe 3 H 2 (g) + N 2 (g) 2 NH 3 (g) 3 molecules + 1 molecule 2 molcules H 2 N 2 NH 3 H-H H H H-H + N-N H-N-H H-N-H H-H 12

13 Molecule to Molecule and Mole to Mole conversions 3 H 2 (g) + N 2 (g) 2 NH 3 (g) This equation may be scaled up if the ratio of H 2 :N 2 :NH 3 is kept 3:1:2 Multiply by 4 12 H 2 (g) + 4N 2 (g) 8 NH 3 (g) Multiply by x x(6.022 x10 23 ) H 2 (g) + 1x(6.022 x10 23 )N 2 (g) 2x(6.022 x10 23 )NH 3 (g) This number of molecules can be expressed as moles. 3 mol H 2 (g) + 1 mol N 2 (g) 2 mol NH 3 (g) 13

14 The coefficients in a balanced equation give the number of molecules as well as the number of moles of each substance We can use the ratios of the coefficients to convert between moles of substances in a chemical reaction

15 8.3 Making Molecules: Mole to Mole Conversions 15

16 Molar Ratios 3 H 2 (g) + N 2 (g) 2 NH 3 (g) This equation has 6 molar ratios relating the reactant and products. For example H 2 and N 2 are related by 1 mole N 2 3 mol H 2 or 3 mol H 2 1 mole N 2

17 Mole to Mole Conversions 3 H 2 (g) + N 2 (g) 2 NH 3 (g) 12 moles of H 2 requires how many mole of N 2 The ratio must be H 2 :N 2 is 3:1, so so 12:4 is the same so 4 mole of N 2 is needed. How many moles of N 2 are needed for 1.74 mol of H 2 17

18 Mole to Mole Conversion 3 H 2 (g) + N 2 (g) 2 NH 3 (g) How many moles of N 2 are needed for 1.74 mol of H 2? We need to use the molar ratio. mol H 2 mole N 2 1 mole N mol H 2 x = mole N 2 3 mol H 2 18

19 8.4 Making Molecule: Mass to Mass Conversions 19

20 20

21 Making Molecules Mass-to-Mass Conversions We learned previously to convert between moles and grams using the molar mass. Combining this with moles to moles conversions allows us to related grams of one substrance in an equation to grams of another substance. g of A mol of A mol of B g of B Molar mass of A Coefficients of the Balanced Equation Molar mass of B 21

22 Example 8.2 How Many Grams of Glucose Can Be Synthesized from 58.5 g of CO 2 in Photosynthesis? Photosynthesis: 6 CO 2 (g) + 6 H 2 O(g) C 6 H 12 O 6 (s) + 6 O 2 (g) g of CO 2 mol of CO 2 mol of C 6 H 12 O 6 g of C 6 H 12 O 6 Molar masses needed (sum masses of all atoms) CO 2 = g/mol Glucose = g/mol 22

23 Grams moles moles grams 6 CO 2 (g) + 6 H 2 O(g) C 6 H 12 O 6 (s) + 6 O 2 (g) 58.5 g CO 2 1 mol CO 2 x = 1.33 mol CO g CO mol g CO 2 1 mol C 6 H 12 O 6 x = mol C 6 H 12 O 6 6 mol CO mol g CO g C 6 H 12 O 6 x = 40.0 g C 6 H 12 O 6 1 mol C 6 H 12 O 6

24 Another stoichiometry example How many g of Al 2 (SO 4 ) 3 are required to completely react with 24.7 g of Ba(NO 3 ) 2? Al 2 (SO 4 ) 3 (aq) + 3Ba(NO 3 ) 2 (aq) 3BaSO 4 (s) + 2Al(NO 3 ) 3 (aq) g of mol of mol of g of Ba(NO 3 ) 2 Ba(NO 3 ) 2 Al 2 (SO 4 ) 3 Al 2 (SO 4 ) 3 molar masses needed Ba(NO 3 ) 2 = g/mol Al 2 (SO 4 ) 3 = g/mol

25 Grams moles moles grams Al 2 (SO 4 ) 3 (aq) + 3Ba(NO 3 ) 2 (aq) 3BaSO 4 (s) +Al(NO 3 ) 3 (aq) 24.7 g Ba(NO 3 ) 2 1 mol Ba(NO 3 ) 2 x = mol Ba(NO 3 ) g Ba(NO 3 ) mol Ba(NO 3 ) 2 1 mol Al 2 (SO 4 ) 3 x = mol Al 2 (SO 4 ) 3 3 mol Ba(NO 3 ) mol g Al 2 (SO 4 ) g Al 2 (SO 4 ) 3 x = 10.8 g Al 2 (SO 4 ) 3 1 mol Al 2 (SO 4 ) 3

26 8.5 More Pancakes: Limiting Reactant, Theoretical Yield, and Percent Yield 8.6 Limiting Reactant, Theoretical Yield, and Percent Yield form Initial Reactants 26

27 Note in these two sections, we are only going to cover percent yield Actual; yield % Yield = x 100 Theoretical yield Actual yield amount actually obtained Theoretical yield amount obtained if reaction goes to 100% completion. 27

28 % yield example A is ran with 100 g of Hg reacting with oxygen grams of HgO is isoloted. What is the % yield? Hg(s) + O 2 (g) Molar masses: Hg = g/mol HgO(s) HgO = g/mol 28

29 % yield example (cont) First calculate the theoretical yield. g Hg mol Hg mol HgO g HgO 100 g Hg 1 mol Hg x g Hg mol Hg 1 mol HgO x 1 mol Hg = mol Hg = mol HgO mol Hg g HgO x = 108 g HgO (theoretical 1 mol HgO yield) 29

30 % yield example 75.0 g HgO % Yield = x g HgO = 69.4 % Yield of HgO. 30

31 Enthalpy Change We previously described processes as exothermic if they released heat, or endothermic if they absorbed heat. The enthalpy of reaction is the amount of thermal energy that flows through a process. At constant pressure. DH rxn 31

32 Sign of Enthalpy Change For exothermic reactions, the sign of the enthalpy change is negative when: Thermal energy is produced by the reaction. The surroundings get hotter. DH = For the reaction CH 4 (s) + 2 O 2 (g) CO 2 (g) + 2 H 2 O(l), the DH rxn = kj per mol of CH 4. For endothermic reactions, the sign of the enthalpy change is positive when: Thermal energy is absorbed by the reaction. The surroundings get colder. DH = + For the reaction N 2 (s) + O 2 (g) 2 NO(g), the DH rxn = kj per mol of N 2. 32

33 Enthalpy and Stoichiometry The amount of energy change in a reaction depends on the amount of reactants. You get twice as much heat out when you burn twice as much CH 4. Writing a reaction implies that amount of energy changes for the stoichiometric amount given in the equation. For the reaction C 3 H 8 (l) + 5 O 2 (g) 3 CO 2 (g) + 4 H 2 O(g) DH rxn = 2044 kj So 1 mol C 3 H 8 5 mol O 2 3 mol CO 2 4 mol H 2 O 2044 kj. 33

34 Enthalpy Calculation C 3 H 8 (l) + 5 O 2 (g) 3 CO 2 (g) + 4 H 2 O(g) DH rxn = 2044 kj How much heat is released when 53.8 g of O2 completely reacts with propane? g O 2 mol O 2 heat (J) 53.8 g of O 2 1 mol O 2 x = 1.68 mol O g O mol of O J x = 687 J of heat 34 5 mol O 2

35 Example 8.7 How Much Heat Is Associated with the Complete Combustion of 11.8 x 10 3 g of C 3 H 8 (g)? Given: Find: Solution Map: Relationships: Solution: x 10 3 g C 3 H 8, heat, kj 1 8 mol C3H g 1 mol C 3 H 8 = kj, Molar mass = g/mol g C g C 3 H 8 3 H 8 1mol C3H g C H mol C 3 H kj 1mol C 3 H kj 1mol C H 3 8 kj kj Check: The sign is correct and the value is reasonable.

36 Practice How Much Heat Is Evolved When a g Diamond Is Burned? (DH combustion = kj/mol C) 36

STOICHIOMETRY ANALOGY

STOICHIOMETRY ANALOGY STOICHIOMETRY ANALOGY Stoichiometry is the quantitative relationship between the reactants and products in a balanced chemical equation. Stoichiometry allows chemists to predict how much of a reactant

More information

STOICHIOMETRY. - the study of the quantitative aspects of chemical

STOICHIOMETRY. - the study of the quantitative aspects of chemical STOICHIOMETRY - the study of the quantitative aspects of chemical GENERAL PLAN FOR STOICHIOMETRY Mass reactant Mass product Moles reactant Stoichiometric factor Moles product STOICHIOMETRY It rests on

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

Thermodynamics. Energy can be used * to provide heat * for mechanical work * to produce electric work * to sustain life

Thermodynamics. Energy can be used * to provide heat * for mechanical work * to produce electric work * to sustain life Thermodynamics Energy can be used * to provide heat * for mechanical work * to produce electric work * to sustain life Thermodynamics is the study of the transformation of energy into heat and for doing

More information

System. System, Boundary and surroundings: Nature of heat and work: Sign convention of heat: Unit-7 Thermodynamics

System. System, Boundary and surroundings: Nature of heat and work: Sign convention of heat: Unit-7 Thermodynamics Unit-7 Thermodynamics Introduction: The term Thermo means heat and dynamics means flow or movement.. So thermodynamics is concerned with the flow of heat. The different forms of the energy are interconvertible

More information

Chapter Six. Energy Relationships in Chemical Reactions

Chapter Six. Energy Relationships in Chemical Reactions Chapter Six Energy Relationships in Chemical Reactions 1 Energy (U): Capacity to Do Work Radiant energy Energy from the sun Nuclear energy Energy stored in the nucleus of an atom Thermal energy Energy

More information

Chapter 5 Thermochemistry

Chapter 5 Thermochemistry Chapter 5 Thermochemistry I. Nature of Energy Energy units SI unit is joule, J From E = 1/2 mv 2, 1J = 1kg. m 2 /s 2 Traditionally, we use the calorie as a unit of energy. 1 cal = 4.184J (exactly) The

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

3. Of energy, work, enthalpy, and heat, how many are state functions? a) 0 b) 1 c) 2 d) 3 e) 4 ANS: c) 2 PAGE: 6.1, 6.2

3. Of energy, work, enthalpy, and heat, how many are state functions? a) 0 b) 1 c) 2 d) 3 e) 4 ANS: c) 2 PAGE: 6.1, 6.2 1. A gas absorbs 0.0 J of heat and then performs 15.2 J of work. The change in internal energy of the gas is a) 24.8 J b) 14.8 J c) 55.2 J d) 15.2 J ANS: d) 15.2 J PAGE: 6.1 2. Calculate the work for the

More information

3A Energy. What is chemical energy?

3A Energy. What is chemical energy? 3A Energy What is chemical energy? Chemical energy is a form of potential energy which is stored in chemical bonds. Chemical bonds are the attractive forces that bind atoms together. As a reaction takes

More information

Chemical Equations and Calculations

Chemical Equations and Calculations Chemical Equations and Calculations A chemical equation is a shorthand way of indicating what is going on in a chemical reaction. We could do it the long way Two molecules of Hydrogen gas react with one

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

PERIODIC TABLE OF ELEMENTS. 4/23/14 Chapter 7: Chemical Reactions 1

PERIODIC TABLE OF ELEMENTS. 4/23/14 Chapter 7: Chemical Reactions 1 PERIODIC TABLE OF ELEMENTS 4/23/14 Chapter 7: Chemical Reactions 1 CHAPTER 7: CHEMICAL REACTIONS 7.1 Describing Reactions 7.2 Types of Reactions 7.3 Energy Changes in Reactions 7.4 Reaction Rates 7.5 Equilibrium

More information

Chapter 4: Chemical and Solution Stoichiometry

Chapter 4: Chemical and Solution Stoichiometry Chapter 4: Chemical and Solution Stoichiometry (Sections 4.1-4.4) 1 Reaction Stoichiometry The coefficients in a balanced chemical equation specify the relative amounts in moles of each of the substances

More information

2. The percent yield is the maximum amount of product that can be produced from the given amount of limiting reactant.

2. 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 information

Standard States. Standard Enthalpy of formation

Standard States. Standard Enthalpy of formation Standard States In any thermochemical equation, the states of all reactants and products must be specified; otherwise it becomes difficult for scientists to understand the experimental results of other

More information

Chapter 6 Quantities in Chemical Reactions

Chapter 6 Quantities in Chemical Reactions Chapter 6 Quantities in Chemical Reactions The Meaning of a Balanced Chemical Equation Mole-Mole Conversions Mass-Mass Conversions Limiting Reactants Percent Yield Energy Changes Copyright The McGraw-Hill

More information

Example: orange juice from frozen concentrate.

Example: orange juice from frozen concentrate. Dilution: a process in which the concentration (molarity) of a solution is lowered. The amount of solute (atoms, moles, grams, etc.) remains the same, but the volume is increased by adding more solvent.

More information

Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions

Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions How do we balance chemical equations? How can we used balanced chemical equations to relate the quantities of substances consumed and produced

More information

Chemistry Stoichiometry. 45 points. Do not turn page until told to do so.

Chemistry Stoichiometry. 45 points. Do not turn page until told to do so. Chemistry 2010 Stoichiometry 45 points Do not turn page until told to do so. Stoichiometry Multiple Choice (Each worth 2 points) Identify the letter of the choice that best completes the statement or

More information

Example. c. Calculate the amount of heat (in kj) required to heat 1.00 kg (~1 L) of water at 25 C to its boiling point.

Example. c. Calculate the amount of heat (in kj) required to heat 1.00 kg (~1 L) of water at 25 C to its boiling point. Example When consuming an ice-cold drink, one must raise the temperature of the beverage to 37.0 C (normal body temperature). Can one lose weight by drinking ice-cold beverages if the body uses up about

More information

AP* Chemistry THERMOCHEMISTRY

AP* Chemistry THERMOCHEMISTRY AP* Chemistry THERMOCHEMISTRY Terms for you to learn that will make this unit understandable: Energy (E) the ability to do work or produce heat ; the sum of all potential and kinetic energy in a system

More information

AP CHEMISTRY 2011 SCORING GUIDELINES

AP CHEMISTRY 2011 SCORING GUIDELINES AP CHEMISTRY 2011 SCORING GUIDELINES Question 3 Hydrogen gas burns in air according to the equation below. 2 H 2 (g) + O 2 (g) 2 H 2 O(l) (a) Calculate the standard enthalpy change, (The molar enthalpy

More information

Ca 3 N 2 (s) + 6H 2 O(l) H 2NH 3 (g) + 3Ca(OH) 2 (s) mole ratio 1 : 6 : 2 : 3 molar mass (g/mole)

Ca 3 N 2 (s) + 6H 2 O(l) H 2NH 3 (g) + 3Ca(OH) 2 (s) mole ratio 1 : 6 : 2 : 3 molar mass (g/mole) 1. STOICHIOMETRY INVOLVING ONLY PURE SUBSTANCES For all chemical reactions, the balanced chemical equation gives the mole ratios of reactants and products. If we are dealing with pure chemicals, the molar

More information

Thermochemistry. Chapter 6. Concept Check 6.1. Concept Check 6.2. Solution

Thermochemistry. Chapter 6. Concept Check 6.1. Concept Check 6.2. Solution Chapter 6 Thermochemistry Concept Check 6.1 A solar-powered water pump has photovoltaic cells on protruding top panels. These cells collect energy from sunlight, storing it momentarily in a battery, which

More information

Energy Changes in Chemical Reactions. System loses heat (negative); gains heat (positive) Describe the difference between the two.

Energy Changes in Chemical Reactions. System loses heat (negative); gains heat (positive) Describe the difference between the two. Energy Changes in Chemical Reactions Most reactions give off or absorb energy Energy is the capacity to do work or supply heat. Heat: transfer of thermal (kinetic) energy between two systems at different

More information

Limiting Reactants and Percentage Yield

Limiting Reactants and Percentage Yield Section 3 Main Ideas One reactant limits the product of a reaction. Comparing the actual and theoretical yields helps chemists determine the reaction s efficiency. Limiting Reactants and Percentage Yield

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

The mass of the formula unit is called the formula mass Formula masses are calculated the same way as molecular masses

The mass of the formula unit is called the formula mass Formula masses are calculated the same way as molecular masses Chapter 4: The Mole Atomic mass provides a means to count atoms by measuring the mass of a sample The periodic table on the inside cover of the text gives atomic masses of the elements The mass of an atom

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

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

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

Chapter 9. Slide 1. Slide 2. Slide 3. Chemical Quantities. Table of Contents

Chapter 9. Slide 1. Slide 2. Slide 3. Chemical Quantities. Table of Contents 1 Chapter 9 Chemical Quantities 2 Chapter 9 Table of Contents 9.1 Information Given by Chemical Equations 9.2 9.3 Copyright Cengage Learning. All rights reserved 2 3 Section 9.1 Information Given by Chemical

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

CHEMISTRY Matter and Change

CHEMISTRY Matter and Change CHEMISTRY Matter and Change CHAPTER 11 Table Of Contents Chapter 11: Stoichiometry Section 1 Section 1 Section 1 Section 1 Describe the types of relationships indicated by a balanced chemical equation.

More information

Chapter 3 Chemical Reactions and Reaction Stoichiometry. 許富銀 ( Hsu Fu-Yin)

Chapter 3 Chemical Reactions and Reaction Stoichiometry. 許富銀 ( Hsu Fu-Yin) Chapter 3 Chemical Reactions and Reaction Stoichiometry 許富銀 ( Hsu Fu-Yin) 1 Stoichiometry The study of the numerical relationship between chemical quantities in a chemical reaction is called stoichiometry.

More information

Some H o f values are tabulated in Table 8.2 (above)

Some H o f values are tabulated in Table 8.2 (above) 8.10 Standard Heats of Formation We cannot have a table for the H values for every reaction there is, because there are too many of them. However, as we saw with Hess s Law, we can express any reaction

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 Dr. M. E. Bridge

Stoichiometry Dr. M. E. Bridge Preliminary Chemistry Course Stoichiometry Dr. M. E. Bridge What is stoichiometry? The meaning of the word: The word stoichiometry comes from two Greek words: (meaning element ) and (meaning measure )

More information

STOICHIOMETRY STOICHIOMETRY. Measurements in Chemical Reactions. Mole-Mole Relationships. Mass-Mass Problem. Mole-Mole Relationships

STOICHIOMETRY STOICHIOMETRY. Measurements in Chemical Reactions. Mole-Mole Relationships. Mass-Mass Problem. Mole-Mole Relationships STOICHIOMETRY STOICHIOMETRY The analysis of the quantities of substances in a chemical reaction. Stoichiometric calculations depend on the MOLE- MOLE relationships of substances. Measurements in Chemical

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

CHEMISTRY Practice exam #4 answer key October 16, 2007

CHEMISTRY Practice exam #4 answer key October 16, 2007 CHEMISTRY 123-01 Practice exam #4 answer key October 16, 2007 1. An endothermic reaction causes the surroundings to a. warm up. b. become acidic. c. condense. 2. Which of the following is an example of

More information

Stoichiometry Chapter 9 Assignment & Problem Set

Stoichiometry Chapter 9 Assignment & Problem Set Stoichiometry Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Stoichiometry 2 Study Guide: Things You Must Know Vocabulary (know the definition

More information

As long as the relative ratios are constant the amounts are correct. Using these ratios to determine quantities is called Stoichiometry.

As long as the relative ratios are constant the amounts are correct. Using these ratios to determine quantities is called Stoichiometry. The Meaning of the Balanced Equation Tuesday, October 11, 2011 2:05 PM The Balanced Equation is a measure of the relative amounts of a compounds that participate in or are produced by a reaction. Since

More information

7.1 Stoichiometry and Percent Yield

7.1 Stoichiometry and Percent Yield score /10 pts. Name Class Date 7.1 Stoichiometry and Percent Yield Mole Ratios An example: The combustion of propane is used to heat many rural homes in winter. Balance the equation below for the combustion

More information

Chapter 5: thermochemstry. Internal Energy: E

Chapter 5: thermochemstry. Internal Energy: E Chapter 5: thermochemstry tonight s goals Energy and Enthalpy Review Enthalpies of Reaction Calorimetry Hess Law Enthalpies of Formation Internal Energy: E E = The sum of all kinetic and potential energies

More information

Chemical Quantities and Aqueous Reactions

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

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

THERMOCHEMISTRY & DEFINITIONS

THERMOCHEMISTRY & DEFINITIONS THERMOCHEMISTRY & DEFINITIONS Thermochemistry is the study of the study of relationships between chemistry and energy. All chemical changes and many physical changes involve exchange of energy with the

More information

Chapter 8: Quantities in Chemical Reactions

Chapter 8: Quantities in Chemical Reactions Ch 8 Page 1 Chapter 8: Quantities in Chemical Reactions Stoichiometry: the numerical relationship between chemical quantities in a balanced chemical equation. Ex. 4NH 3 + 5O 2 4NO + 6H 2 O The reaction

More information

Stoichiometry: Calculations with Chemical Equations

Stoichiometry: Calculations with Chemical Equations Stoichiometry: Calculations with Chemical Equations Objectives Use chemical equations to predict amount of product from given reactants Determine percentage yield Determine limiting reactant Working with

More information

Name Date Class THERMOCHEMISTRY. SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510)

Name Date Class THERMOCHEMISTRY. SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510) 17 THERMOCHEMISTRY SECTION 17.1 THE FLOW OF ENERGY HEAT AND WORK (pages 505 510) This section explains the relationship between energy and heat, and distinguishes between heat capacity and specific heat.

More information

Thermochemistry. Thermochemistry 1/25/2010. Reading: Chapter 5 (omit 5.8) As you read ask yourself

Thermochemistry. Thermochemistry 1/25/2010. Reading: Chapter 5 (omit 5.8) As you read ask yourself Thermochemistry Reading: Chapter 5 (omit 5.8) As you read ask yourself What is meant by the terms system and surroundings? How are they related to each other? How does energy get transferred between them?

More information

4. Aluminum chloride is 20.2% aluminum by mass. Calculate the mass of aluminum in a 35.0 gram sample of aluminum chloride.

4. Aluminum chloride is 20.2% aluminum by mass. Calculate the mass of aluminum in a 35.0 gram sample of aluminum chloride. 1. Calculate the molecular mass of table sugar sucrose (C 12 H 22 O 11 ). A. 342.30 amu C. 320.05 amu B. 160.03 amu D. 171.15 amu 2. How many oxygen atoms are in 34.5 g of NaNO 3? A. 2.34 10 23 atoms C.

More information

2 NO + O 2 2 NO 2 3/18/2014. iclicker Participation Question: A B C

2 NO + O 2 2 NO 2 3/18/2014. iclicker Participation Question: A B C Today: Stoichiometric Analysis: Gram to Gram Conversions: Use MOLAR MASS to get to moles Limiting Reagents: Method 1 Method 2 Actual Yield & Percent Yield Combustion Analysis Titrations Next Meeting Reading

More information

Section 9.1. Using Chemical Equations

Section 9.1. Using Chemical Equations 1984, Union Carbide Plant 10000+ killed in Bhopal, India by Methyl Isocyanate 1988 Pepcon, Henderson Rocket Fuel Explosion Objectives 1. To understand more of the information given in a balanced equation

More information

Chapter 5 Chemical Quantities and Reactions

Chapter 5 Chemical Quantities and Reactions Chapter 5 Chemical Quantities and Reactions 1 Avogadro's Number Small particles such as atoms, molecules, and ions are counted using the mole. 1 mole = 6.02 x 10 23 items Avogadro s number 602 000 000

More information

ENERGY. Thermochemistry. Heat. Temperature & Heat. Thermometers & Temperature. Temperature & Heat. Energy is the capacity to do work.

ENERGY. Thermochemistry. Heat. Temperature & Heat. Thermometers & Temperature. Temperature & Heat. Energy is the capacity to do work. ENERGY Thermochemistry Energy is the capacity to do work. Chapter 6 Kinetic Energy thermal, mechanical, electrical, sound Potential Energy chemical, gravitational, electrostatic Heat Heat, or thermal energy,

More information

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

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

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

Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions

Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions Chapter 7: Stoichiometry - Mass Relations in Chemical Reactions How do we balance chemical equations? How can we used balanced chemical equations to relate the quantities of substances consumed and produced

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

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

Subscripts and Coefficients Give Different Information

Subscripts and Coefficients Give Different Information Chapter 3: Stoichiometry Goal is to understand and become proficient at working with: 1. Chemical equations (Balancing REVIEW) 2. Some simple patterns of reactivity 3. Formula weights (REVIEW) 4. Avogadro's

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

Bomb Calorimetry. Example 4. Energy and Enthalpy

Bomb Calorimetry. Example 4. Energy and Enthalpy Bomb Calorimetry constant volume often used for combustion reactions heat released by reaction is absorbed by calorimeter contents need heat capacity of calorimeter q cal = q rxn = q bomb + q water Example

More information

10 Cl atoms. 10 H2O molecules. 8.3 mol HCN = 8.3 mol N atoms 1 mol HCN. 2 mol H atoms 2.63 mol CH2O = 5.26 mol H atoms 1 mol CH O

10 Cl atoms. 10 H2O molecules. 8.3 mol HCN = 8.3 mol N atoms 1 mol HCN. 2 mol H atoms 2.63 mol CH2O = 5.26 mol H atoms 1 mol CH O Chem 100 Mole conversions and stoichiometry worksheet 1. How many Ag atoms are in.4 mol Ag atoms? 6.0 10 Ag atoms 4.4 mol Ag atoms = 1.46 10 Ag atoms 1 mol Ag atoms. How many Br molecules are in 18. mol

More information

DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3

DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3 DETERMINING THE ENTHALPY OF FORMATION OF CaCO 3 Standard Enthalpy Change Standard Enthalpy Change for a reaction, symbolized as H 0 298, is defined as The enthalpy change when the molar quantities of reactants

More information

Balanced Chemical Reaction Equations

Balanced Chemical Reaction Equations Activity 5 Balanced Chemical Reaction Equations Why? Chemical reaction equations are fundamental tools for communicating how chemical compounds are synthesized and changed. Representing a chemical reaction

More information

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

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

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 5. Thermochemistry

Chapter 5. Thermochemistry Chapter 5. Thermochemistry THERMODYNAMICS - study of energy and its transformations Thermochemistry - study of energy changes associated with chemical reactions Energy - capacity to do work or to transfer

More information

Lecture 5 Outline. Derived from the Greek stoicheion ( element ) and metron ( measure )

Lecture 5 Outline. Derived from the Greek stoicheion ( element ) and metron ( measure ) Lecture 5 Outline 5.1 Stoichiometry,, the mole etc. 5.2 Chemical Equations 5.3 Molarity 5.4 Limiting reagents and yields 5.5 Reaction enthalpies and Gibbs free energy 5.6 Catalyst Lecture 5 Stoichiometry

More information

Chapter 4 Chemical Equations & Stoichiometry

Chapter 4 Chemical Equations & Stoichiometry Chapter 4 Chemical Equations & Stoichiometry Chemical reactions are best described using equations which tells us what compounds we started with (reactants), what we did to them (reaction conditions) and

More information

AP Chemistry. Unit #3. Chapter 3 Zumdahl

AP Chemistry. Unit #3. Chapter 3 Zumdahl AP Chemistry Unit #3 Chapter 3 Zumdahl Stoichiometry C6H12O6 + 6 O2 6 CO2 + 6 H2O Students should be able to: Calculate the atomic weight (average atomic mass) of an element from the relative abundances

More information

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry

The Relationships Between. Internal Energy, Heat, Enthalpy, and Calorimetry The Relationships Between Internal Energy, Heat, Enthalpy, and Calorimetry Recap of Last Class Last class, we began our discussion about energy changes that accompany chemical reactions Chapter 5 discusses:

More information

Chemistry Guide

Chemistry Guide 551534 - Chemistry Guide 1- Contents Question Item Objective Type Skill 1 0102 M03.02.04 Multiple-choice answer Mastery of Problem Solving 2 0099 M03.03.02 Multiple-choice answer Mastery of Concepts 3

More information

Tuesday, October 23rd. Review Quiz Finish Chapter 6, Begin Chapter 7 Group Assignment

Tuesday, October 23rd. Review Quiz Finish Chapter 6, Begin Chapter 7 Group Assignment Tuesday, October 23rd Review Quiz Finish Chapter 6, Begin Chapter 7 Group Assignment 1 Review 2 Naming Ionic Compounds - When a metal is bonded to a nonmetal: 1. Name the metal. 2. Name the anion, use

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

Chapter 14. CHEMICAL EQUILIBRIUM

Chapter 14. CHEMICAL EQUILIBRIUM Chapter 14. CHEMICAL EQUILIBRIUM 14.1 THE CONCEPT OF EQUILIBRIUM AND THE EQUILIBRIUM CONSTANT Many chemical reactions do not go to completion but instead attain a state of chemical equilibrium. Chemical

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

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

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

SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS

SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS SUPPLEMENTARY TOPIC 3 ENERGY AND CHEMICAL REACTIONS Rearranging atoms. In a chemical reaction, bonds between atoms in one or more molecules (reactants) break and new bonds are formed with other atoms to

More information

Calorimetry and Enthalpy. Chapter 5.2

Calorimetry and Enthalpy. Chapter 5.2 Calorimetry and Enthalpy Chapter 5.2 Heat Capacity Specific heat capacity (c) is the quantity of thermal energy required to raise the temperature of 1g of a substance by 1⁰C The units for specific heat

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

Chapter 5 Thermo. Energy & Chemistry. Energy & Chemistry. Units of Energy. Energy & Chemistry. Potential & Kinetic Energy. Some Basic Principles

Chapter 5 Thermo. Energy & Chemistry. Energy & Chemistry. Units of Energy. Energy & Chemistry. Potential & Kinetic Energy. Some Basic Principles 1 Energy & Chemistry effrey Mack California State University, Sacramento Chapter 5 Principles of Chemical Reactivity: Energy and Chemical Reactions Questions that need to be addressed: How do we measure

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

Chapter 6 Chemical Reactions: An Introduction

Chapter 6 Chemical Reactions: An Introduction Chapter 6 Chemical Reactions: An Introduction Chemical Reactions Reactions involve chemical changes in matter that result in new substances. Reactions involve rearrangement and exchange of atoms to produce

More information

1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics

1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics Chem 105 Fri 10-23-09 1. Thermite reaction 2. Enthalpy of reaction, H 3. Heating/cooling curves and changes in state 4. More thermite thermodynamics 10/23/2009 1 Please PICK UP your graded EXAM in front.

More information

Form A. CORRECT: As gases mix, the disorder or number of microstates with the same energy increases. As a result, entropy increases as well.

Form A. CORRECT: As gases mix, the disorder or number of microstates with the same energy increases. As a result, entropy increases as well. Chem 130 Name Exam 3, Ch 7, 19, and a little 14 November 11, 2011 100 Points Please follow the instructions for each section of the exam. Show your work on all mathematical problems. Provide answers with

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

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

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

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

More information

Energy and Chemical Reactions. Characterizing Energy:

Energy and Chemical Reactions. Characterizing Energy: Energy and Chemical Reactions Energy: Critical for virtually all aspects of chemistry Defined as: We focus on energy transfer. We observe energy changes in: Heat Transfer: How much energy can a material

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

Mr. Bracken. Multiple Choice Review: Thermochemistry

Mr. Bracken. Multiple Choice Review: Thermochemistry Mr. Bracken AP Chemistry Name Period Multiple Choice Review: Thermochemistry 1. If this has a negative value for a process, then the process occurs spontaneously. 2. This is a measure of how the disorder

More information

The Mole. S We are familiar with using a specific term to represent a number of items in a group.

The Mole. S We are familiar with using a specific term to represent a number of items in a group. Unit 5 The Mole S The Mole S We are familiar with using a specific term to represent a number of items in a group. S 1 dozen = 12 units of something S 1 case of Cokes = 24 Cokes S In chemistry we use the

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

EMPIRICAL AND MOLECULAR FORMULA

EMPIRICAL AND MOLECULAR FORMULA EMPIRICAL AND MOLECULAR FORMULA Percent Composition: law of constant composition states that any sample of a pure compound always consists of the same elements combined in the same proportions by mass

More information