General, Organic, and Biological Chemistry Fourth Edition Karen Timberlake 6.6 Mole Relationships in Chemical Equations Chapter 6 Chemical Reactions and Quantities © 2013 Pearson Education, Inc. Lectures

© 2013 Pearson Education, Inc. Chapter 6, Section 6 2 Law of Conservation of Mass The Law of Conservation of Mass indicates that in an ordinary chemical reaction,  matter can neither be created nor destroyed and that  the total mass of products is equal to the total mass of reactants.

© 2013 Pearson Education, Inc. Chapter 6, Section 6 3 Conservation of Mass

© 2013 Pearson Education, Inc. Chapter 6, Section 6 4 Information from a Balanced Equation

© 2013 Pearson Education, Inc. Chapter 6, Section 6 5 Consider the following equation: An equation can be read in “moles” by placing the words “moles of” between each coefficient and formula. Chemical Equations: Moles–Moles

© 2013 Pearson Education, Inc. Chapter 6, Section 6 6 In the chemical reaction of Fe and S, the mass of the reactants is the same as the mass of the product, Fe 2 S 3. Chemical Equations: Moles–Moles

© 2013 Pearson Education, Inc. Chapter 6, Section 6 7 A mole–mole factor is a ratio of the moles (from the coefficients) for any two substances in an equation. Mole–Mole Factors from Chemical Equations

© 2013 Pearson Education, Inc. Chapter 6, Section 6 8 Consider the following equation. 1. A mole–mole factor for H 2 and N 2 is A.B.C. 2. A mole–mole factor for NH 3 and H 2 is A.B.C. Learning Check

© 2013 Pearson Education, Inc. Chapter 6, Section 6 9 Consider the following equation. 1. A mole–mole factor for H 2 and N 2 is B. 2. A mole–mole factor for NH 3 and H 2 is B. Solution

© 2013 Pearson Education, Inc. Chapter 6, Section 6 10 Guide to Calculating Quantities in a Chemical Reaction

© 2013 Pearson Education, Inc. Chapter 6, Section 6 11 How many moles of CO 2 can be produced when 2.25 moles of C 3 H 8 react according to the following balanced reaction? Step 1 State the given and needed quantities. Analyze the Problem. Calculating Quantities in a Chemical Reaction

© 2013 Pearson Education, Inc. Chapter 6, Section 6 12 How many moles of CO 2 can be produced when 2.25 moles of C 3 H 8 react according to the following balanced reaction? Step 2 Write a plan to convert the given to the needed quantity (moles or grams). moles of C 3 H 8 mole–mole factor moles of CO 2 Calculating Quantities in a Chemical Reaction

© 2013 Pearson Education, Inc. Chapter 6, Section 6 13 How many moles of CO 2 can be produced when 2.25 moles of C 3 H 8 react according to the following balanced reaction? Step 3 Use coefficients to write mole–mole factors; write molar mass factors if needed. 1 mole of C 3 H 8 = 3 moles of CO 2 Calculating Quantities in a Chemical Reaction

© 2013 Pearson Education, Inc. Chapter 6, Section 6 14 How many moles of CO 2 can be produced when 2.25 moles of C 3 H 8 react according to the following balanced reaction? Step 4 Set up the problem to give the needed quantity (moles or grams). Calculating Quantities in a Chemical Reaction

© 2013 Pearson Education, Inc. Chapter 6, Section 6 15 How many moles of Fe are needed for the reaction of 12.0 moles of O 2 ? A moles of Fe B moles of Fe C moles of Fe Learning Check

© 2013 Pearson Education, Inc. Chapter 6, Section 6 16 How many moles of Fe are needed for the reaction of 12.0 moles of O 2 ? Step 1 State the given and needed quantities. Analyze the Problem. Solution

© 2013 Pearson Education, Inc. Chapter 6, Section 6 17 How many moles of Fe are needed for the reaction of 12.0 moles of O 2 ? Step 2 Write a plan to convert the given to the needed quantity (moles or grams) moles of O 2 mole–mole factor moles of Fe Solution

© 2013 Pearson Education, Inc. Chapter 6, Section 6 18 How many moles of Fe are needed for the reaction of 12.0 moles of O 2 ? Step 3 Use coefficients to write mole–mole factors; write molar mass factors if needed. 4 moles of Fe = 3 moles of O 2 Solution

© 2013 Pearson Education, Inc. Chapter 6, Section 6 19 How many moles of Fe are needed for the reaction of 12.0 moles of O 2 ? Step 4 Set up the problem to give the needed quantity (moles or grams). Answer is C. Solution