Monday January 23rd CHAPTER 10

Save this PDF as:
 WORD  PNG  TXT  JPG

Size: px
Start display at page:

Download "Monday January 23rd CHAPTER 10"

Transcription

1 Monday January 23rd BELL WORK: In what quantity do eggs usually come in at the store? How many gloves do you usually buy at one time? What is a group of pencils that you might buy at the store called? CHAPTER 10 Chemists wanted a method for accurately counting atoms, molecules, or formula units..the problem was that they are so small that they can not be directly counted. (Can you imagine sitting at a desk counting the number of atoms in a penny?) -Chemists created a counting unit called the mole (mol) Mole- (mol) SI base unit to measure the amount of a substance -defined as the number of carbon atoms in a 12g of pure carbon-12 -a mole of anything is 6.02x10 23 moles, referred to as Avogadro's number 1

2 Let's say I bought 3.5 dozen flowers for valentines day and I wanted to know exactly how many flowers I had. How would I do it? How many particles of sucrose are in 3.5 moles of sucrose? Conversion factor: 1 mol of particles = 6.02x10 23 particles 2

3 The mass of 1 dozen eggs is NOT the same as the mass of 1 dozen lemons. Regardless of the fact that I have the same amount of them. This is the same thing for different elements. REMEMBER the mole is defined as the number of carbon-12 atoms in exactly 12 grams of pure carbon 12. Therefore the mass of 1 mole of it is 12g. The masses of all other elements are based around carbon. The mass in grams of one mole of any pure substance is called molar mass. The mass in grams of one mole of any pure substance is called molar mass. **The molar mass of any element is numerically equivalent to its atomic mass and has the units g/mol. Example: 1 mol or 6.02x10 23 atoms of iron has the mass of g. Its molar mass is g/mol Example Problem: I know that 1 dozen jellybeans = 35g jelly beans. What mass of jellybeans should you measure if a customer wants 5 dozen jelly beans? 3

4 Example Problem: Suppose that while working in a chemistry lab, you need 3.00mol of copper for a chemical reaction. How would you measure that amount? number of moles x mass in grams = mass 1 mole Example Problem: How many moles of calcium are in 525g Calcium? molar mass = 40.08g/mol of calcium 4

5 Example problem: Gold is one of a group of metals called the coinage metals. How many atoms of gold are in a U.S. Eagle, a gold alloy bullion coin with a mass of 31.1g Au? NOTE: If your asked for atoms, particles, molecules you will use Avogadro's number for all of them. Homework Practice problems: #1-2 page 323 #5 page 324 #15-16a page 328 #17-18a page 329 #19-20c page 331 5

6 Tuesday January 24th Check your homework with the board. We can make similar conversions for compounds and ions but you need to know the molar mass of the compound and the ions involved first. A chemical formula indicates the number(s) and types of atoms contained in one unit of the compound. Example: CCl 4 There is 1 carbon molecule and 4 chlorine molecules making up the compound carbon tetrachloride. If I had 1 mole of it I would have the same ratio of elements involved AND 1 mole would still be equivalent to Avogadro's number. If I had a dozen CCl 4 molecules or 12CCl 4 I would have 12 carbon and 48 chlorine. I would have 12 moles of carbon to 48 moles of chlorine. 6

7 Some chemical calculations require you to convert between moles of a compound and moles of individual atoms in the compound. To do this you must create ratios that work as conversion factors. Example: CCl 2 F 2 1 mole C atoms 2 moles Cl atoms 2 mole F atoms 1 mole CCl 2 F 2 1 mole CCl 2 F 2 1 mole CCl 2 F 2 Example Problem: How many moles of fluorine atoms are in 5.50 moles of Freon (CCl 2 F 2 )? 5.50 moles CCl 2 F 2 2 moles F 11 moles of F 1 mole CCl 2 F atoms 2 We treat ions the same way. Example: Aluminum oxide (Al 2 O 3 ) is the principal raw material for the production of aluminum. Determine the moles of aluminum ions (Al 3+ ) in 1.25 mol of Al 2 O 3. Conversion Factor: 2 moles Al 3+ ions 1 mol Al 2 O mol Al 2 O 3 2 mole Al 3+ ions 1 mol Al 2 O mol Al 3+ ions NOTE: conversion factors are not used when considering sigfigs! 7

8 MOLAR MASS OF COMPOUNDS If I wanted to know what my back pack weighs BUT it is too heavy to stick the entire thing on a scale at once...how could I do it? Stick everything that is in the backpack on the scale and add it all up Similarly the mass of a mole of a compound = the sum of the masses of all the particles that make up the compound. Example: Find the molar mass of potassium chromate (K 2 CrO 4 ) 2 mol K g K 1 mol K 1 mol Cr 52.00g Cr 1 mol Cr 78.20g 52.00g g 4 mol O g O 1 mol O 64.00g Homework: Practice Problems & 34a b, 35a b, all of 36 on page 335 8

9 CONVERTING MOLES OF A COMPOUND TO MASS This process is the SAME as it was for elements BUT you need the molar mass of a compound first. Example Problem: What is the mass of 2.50 mol of (C 3 H 5 ) 2 S? **Must convert the moles to mass using the molar mass as a conversion factor** 1 mol S g S 1 mol S 32.07g S 6 mol C g C 1 mol C g C g/mol of (C 3 H 5 ) 2 S 10mol H 1.008g H 1 mol H 10.08g H 2.50 mol (C3H5)2S g (C 3 H 5 ) 2 S 1 mol (C 3 H 5 ) 2 S 286 g (C 3 H 5 ) 2 S CONVERTING THE MASS OF A COMPOUND TO MOLES -Backwards of the example I just showed. CONVERTING THE MASS OF A COMPOUND TO THE NUMBER OF PARTICLES -2 STEP PROCESS 1. convert mass to moles 2. convert moles to particles/atoms/molecules etc. by using Avogadro's number Example: Aluminum chloride (AlCl3) is used in refining petroleum, etc. A sample has a mass of 35.6g. a. How many aluminum ions are present? b. How many chloride ions are present? c. What is the mass, in grams, of one formula unit of aluminum chloride? 1 mol Al 26.98g Al 1 mol Al 3 mol Cl 35.45g Cl 1 mol Cl 26.98g Al g Cl g/mol AlCl 3 9

10 133.33g/mol AlCl g AlCl 3 1 mol AlCl g AlCl mol of AlCl mol AlCl x10 23 formula units 1 mol 1.61 x10 23 formula units of AlCl 3 Part A: 1.61 x 1023 formula units AlCl 3 1Al 3+ ion 1 formula unit 1.61 x Al 3+ ions Part B: Same idea as Part A. conversion factor will be 3 to 1. Answer: 4.83 x10 23 Cl- ions Part C: g AlCl 3 1 mol AlCl 3 1 mol 6.02 x formula units = 2.21 x 10-22g AlCl3/formula unit Percent Composition The percent by mass of any element in a compound can be found by dividing the mass of the element by the mass of the compound and multiplying by 100. Percent by mass (element) = mass of element mass of compound 100 **Mass Percents of a compound must always add up to 100. Percent composition- the percent by mass of each element in a compound 10

11 You can also determine the percent composition from the chemical formula. -Assume you have exactly 1 mol of the compound and use the chemical formula to calculate the compound's molar mass. Percent by Mass from the chemical formula percent by mass = mass of element in 1 mol of compound molar mass of compound 100 Example Problem: Determine the percent composition of NaHCO 3 First: Assume you have 1 mol of NaHCO 3 Second: Determine the molar mass of NaHCO 3 1 mol Na 22.99g Na 1 mol Na 22.99g Na 1 mol H 1.008g H 1 mol H 1 mol C 12.01g C 1 mol C 1.008g H 12.01g C 84.01g/mol NaHCO 3 3 mol O 16.00g O 1 mol O 48.00g O 11

12 Third: Use the percent by mass equation. % mass of element = mass of element in 1 mol of compound molar mass of the compound x 100 percent Na = 22.99g/mol Na X 100 = 27.37% Na 84.01g/mol NaHCO g 1 mol 1 mol 84.01g **Continue to do the same process with each element in the compound to find the mass % of each element.** Try One! 1. Find the % composition of CU 2 S 2. Find the % composition of Ba(NO 3 ) 2 12

13 Homework: page page page page

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

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

2 The Structure of Atoms

2 The Structure of Atoms CHAPTER 4 2 The Structure of Atoms SECTION Atoms KEY IDEAS As you read this section, keep these questions in mind: What do atoms of the same element have in common? What are isotopes? How is an element

More information

The Mole Concept and Atoms

The Mole Concept and Atoms Copyright The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Chapter 4 24 September 2013 Calculations and the Chemical Equation The Mole Concept and Atoms Atoms are exceedingly

More 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

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

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

Study Guide For Chapter 7

Study Guide For Chapter 7 Name: Class: Date: ID: A Study Guide For Chapter 7 Multiple Choice Identify the choice that best completes the statement or answers the question. 1. The number of atoms in a mole of any pure substance

More 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

Introductory Chemistry Fourth Edition Nivaldo J. Tro

Introductory Chemistry Fourth Edition Nivaldo J. Tro Introductory Chemistry Fourth Edition Nivaldo J. Tro Chapter 6 Chemical Composition Dr. Sylvia Esjornson Southwestern Oklahoma State University Weatherford, OK 6.1 How Much Sodium? Sodium is an important

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

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

Chemical Composition Review Mole Calculations Percent Composition. Copyright Cengage Learning. All rights reserved. 8 1

Chemical Composition Review Mole Calculations Percent Composition. Copyright Cengage Learning. All rights reserved. 8 1 Chemical Composition Review Mole Calculations Percent Composition Copyright Cengage Learning. All rights reserved. 8 1 QUESTION Suppose you work in a hardware store and a customer wants to purchase 500

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

= 16.00 amu. = 39.10 amu

= 16.00 amu. = 39.10 amu Using Chemical Formulas Objective 1: Calculate the formula mass or molar mass of any given compound. The Formula Mass of any molecule, formula unit, or ion is the sum of the average atomic masses of all

More 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

A dozen. Molar Mass. Mass of atoms

A dozen. Molar Mass. Mass of atoms A dozen Molar Mass Science 10 is a number of objects. A dozen eggs, a dozen cars, and a dozen people are all 12 objects. But a dozen cars has a much greater mass than a dozen eggs because the mass of each

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 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

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

Chemistry 65 Chapter 6 THE MOLE CONCEPT

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

More information

CH3 Stoichiometry. The violent chemical reaction of bromine and phosphorus. P.76

CH3 Stoichiometry. The violent chemical reaction of bromine and phosphorus. P.76 CH3 Stoichiometry The violent chemical reaction of bromine and phosphorus. P.76 Contents 3.1 Counting by Weighing 3.2 Atomic Masses 3.3 The Mole 3.4 Molar Mass 3.5 Percent Composition of Compounds 3.6

More information

Ch. 6 Chemical Composition and Stoichiometry

Ch. 6 Chemical Composition and Stoichiometry Ch. 6 Chemical Composition and Stoichiometry The Mole Concept [6.2, 6.3] Conversions between g mol atoms [6.3, 6.4, 6.5] Mass Percent [6.6, 6.7] Empirical and Molecular Formula [6.8, 6.9] Bring your calculators!

More 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

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

What s in a Mole? Molar Mass

What s in a Mole? Molar Mass LESSON 10 What s in a Mole? Molar Mass OVERVIEW Key Ideas Lesson Type Lab: Groups of 4 Chemists compare moles of substances rather than masses because moles are a way of counting atoms. When considering

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

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

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

Description of the Mole Concept:

Description of the Mole Concept: Description of the Mole Concept: Suppose you were sent into the store to buy 36 eggs. When you picked them up you would get 3 boxes, each containing 12 eggs. You just used a mathematical device, called

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

Chapter 6: Chemical Composition

Chapter 6: Chemical Composition C h e m i s t r y 1 2 C h 6 : C h e m i c a l C o m p o s i t i o n P a g e 1 Chapter 6: Chemical Composition Bonus: 17, 21, 31, 39, 43, 47, 55, 61, 63, 69, 71, 77, 81, 85, 91, 95, 97, 99 Check the deadlines

More information

10.3 Percent Composition and Chemical Formulas

10.3 Percent Composition and Chemical Formulas Name Class Date 10.3 Percent Composition and Chemical Formulas Essential Understanding of its empirical formula. A molecular formula of a compound is a whole-number multiple Lesson Summary Percent Composition

More information

Chapter 8 How to Do Chemical Calculations

Chapter 8 How to Do Chemical Calculations Chapter 8 How to Do Chemical Calculations Chemistry is both a qualitative and a quantitative science. In the laboratory, it is important to be able to measure quantities of chemical substances and, as

More information

Matter. Atomic weight, Molecular weight and Mole

Matter. Atomic weight, Molecular weight and Mole Matter Atomic weight, Molecular weight and Mole Atomic Mass Unit Chemists of the nineteenth century realized that, in order to measure the mass of an atomic particle, it was useless to use the standard

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

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

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

SYMBOLS, FORMULAS AND MOLAR MASSES

SYMBOLS, FORMULAS AND MOLAR MASSES SYMBOLS, FORMULAS AND MOLAR MASSES OBJECTIVES 1. To correctly write and interpret chemical formulas 2. To calculate molecular weights from chemical formulas 3. To calculate moles from grams using chemical

More information

Molar Mass Worksheet Answer Key

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

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

Name Date Class CHEMICAL QUANTITIES. SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296)

Name Date Class CHEMICAL QUANTITIES. SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296) Name Date Class 10 CHEMICAL QUANTITIES SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296) This section defines the mole and explains how the mole is used to measure matter. It also teaches

More 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

The Mole CHAPTER 11. What You ll Learn You will use the mole and molar mass to make conversions among moles, mass, and number of representative

The Mole CHAPTER 11. What You ll Learn You will use the mole and molar mass to make conversions among moles, mass, and number of representative CHAPTER 11 The Mole Chemistry 3.b, 3.c, 3.d I&E 1.b, 1.c, 1.d, 1.e, 1.l What You ll Learn You will use the mole and molar mass to make conversions among moles, mass, and number of representative particles.

More information

3.3 Moles, 3.4 Molar Mass, and 3.5 Percent Composition

3.3 Moles, 3.4 Molar Mass, and 3.5 Percent Composition 3.3 Moles, 3.4 Molar Mass, and 3.5 Percent Composition Collection Terms A collection term states a specific number of items. 1 dozen donuts = 12 donuts 1 ream of paper = 500 sheets 1 case = 24 cans Copyright

More information

Relative Mass and the Mole

Relative Mass and the Mole Why? Relative Mass and the Mole How can atoms be counted using a balance? Consider the following equation for a chemical reaction: 2H 2 + O 2 2H 2 O This can be interpreted as two molecules of hydrogen

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

10.3 Percent Composition and Chemical Formulas. Chapter 10 Chemical Quantities Percent Composition and Chemical Formulas

10.3 Percent Composition and Chemical Formulas. Chapter 10 Chemical Quantities Percent Composition and Chemical Formulas Chapter 10 Chemical Quantities 101 The Mole: A Measurement of Matter 102 Mole-Mass and Mole-Volume Relationships 103 Percent Composition and Chemical Formulas 1 CHEMISTRY & YOU What does the percent composition

More information

CHAPTER 3 Calculations with Chemical Formulas and Equations. atoms in a FORMULA UNIT

CHAPTER 3 Calculations with Chemical Formulas and Equations. atoms in a FORMULA UNIT CHAPTER 3 Calculations with Chemical Formulas and Equations MOLECULAR WEIGHT (M. W.) Sum of the Atomic Weights of all atoms in a MOLECULE of a substance. FORMULA WEIGHT (F. W.) Sum of the atomic Weights

More information

Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test

Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test Unit 3 Notepack Chapter 7 Chemical Quantities Qualifier for Test NAME Section 7.1 The Mole: A Measurement of Matter A. What is a mole? 1. Chemistry is a quantitative science. What does this term mean?

More information

Name Date Class CHEMICAL QUANTITIES. SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296)

Name Date Class CHEMICAL QUANTITIES. SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296) 10 CHEMICAL QUANTITIES SECTION 10.1 THE MOLE: A MEASUREMENT OF MATTER (pages 287 296) This section defines the mole and explains how the mole is used to measure matter. It also teaches you how to calculate

More 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

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

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

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

Programme in mole calculation

Programme in mole calculation Programme in mole calculation Step 1 Start at the very beginning Atoms are very small indeed! If we draw a line 1 metre long, 6,000,000,000 (6 billion) atoms could be lined end to end. So a scientist cannot

More information

MOLAR MASS AND MOLECULAR WEIGHT Themolar mass of a molecule is the sum of the atomic weights of all atoms in the molecule. Molar Mass.

MOLAR MASS AND MOLECULAR WEIGHT Themolar mass of a molecule is the sum of the atomic weights of all atoms in the molecule. Molar Mass. Counting Atoms Mg burns in air (O 2 ) to produce white magnesium oxide, MgO. How can we figure out how much oxide is produced from a given mass of Mg? PROBLEM: If If 0.200 g of Mg is is burned, how much

More information

Tuesday, November 27, 2012 Expectations:

Tuesday, November 27, 2012 Expectations: Tuesday, November 27, 2012 Expectations: Sit in assigned seat Get out Folder, Notebook, Periodic Table Have out: Spiral (notes), Learning Target Log (new) No Backpacks on tables Listen/Pay Attention Learning

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

Moles Lab mole. 1 mole = 6.02 x 1023. This is also known as Avagadro's number Demo amu amu amu

Moles Lab mole. 1 mole = 6.02 x 1023. This is also known as Avagadro's number Demo amu amu amu Moles I. Lab: Rice Counting II. Counting atoms and molecules I. When doing reactions chemists need to count atoms and molecules. The problem of actually counting individual atoms and molecules comes from

More information

b. N 2 H 4 c. aluminum oxalate d. acetic acid e. arsenic PART 2: MOLAR MASS 2. Determine the molar mass for each of the following. a. ZnI 2 b.

b. N 2 H 4 c. aluminum oxalate d. acetic acid e. arsenic PART 2: MOLAR MASS 2. Determine the molar mass for each of the following. a. ZnI 2 b. CHEMISTRY DISCOVER UNIT 5 LOTS OF PRACTICE ON USING THE MOLE!!! PART 1: ATOMIC MASS, FORMULA MASS, OR MOLECULAR MASS 1. Determine the atomic mass, formula mass, or molecular mass for each of the following

More information

The Mole IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES

The Mole IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES The Mole S 6.02 X 10 23 IT IS JUST A STANDARD NUMBER OF ATOMS/MOLECULES Relative Masses To understand relative scales, let s s ignore electrons and compare atoms by total number of nuclear particles. Hydrogen,

More information

Moles, Molecules, and Grams Worksheet Answer Key

Moles, Molecules, and Grams Worksheet Answer Key Moles, Molecules, and Grams Worksheet Answer Key 1) How many are there in 24 grams of FeF 3? 1.28 x 10 23 2) How many are there in 450 grams of Na 2 SO 4? 1.91 x 10 24 3) How many grams are there in 2.3

More 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

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

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

BALANCING CHEMICAL EQUATIONS

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

More information

Chemistry Post-Enrolment Worksheet

Chemistry Post-Enrolment Worksheet Name: Chemistry Post-Enrolment Worksheet The purpose of this worksheet is to get you to recap some of the fundamental concepts that you studied at GCSE and introduce some of the concepts that will be part

More information

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

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

More information

Unit 7A - The Mole. We Need to Count atoms. The Mole and Molar Mass

Unit 7A - The Mole. We Need to Count atoms. The Mole and Molar Mass Unit 7A - The Mole The Mole and Molar Mass We Need to Count atoms Airbags are inflated by a chemical reaction: electrical 2 NaN 3 (s) 3 N 2 (g) + 2 Na(s) decomposition Each airbag needs the right amount

More information

Useful only for measuring the mass of very small objects atoms and molecules!

Useful only for measuring the mass of very small objects atoms and molecules! Chapter 9 Chemical Composition (Moles) Which weighs more, 1 atom of He or 1 atom of O? Units of mass: Pound Kilogram Atomic mass unit (AMU) There are others! 1 amu = 1.66 x 10-24 grams = mass of a proton

More information

The Mole. Chapter 2. Solutions for Practice Problems

The Mole. Chapter 2. Solutions for Practice Problems Chapter 2 The Mole Note to teacher: You will notice that there are two different formats for the Sample Problems in the student textbook. Where appropriate, the Sample Problem contains the full set of

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 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

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

Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry

Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Chem 115 POGIL Worksheet - Week 4 Moles & Stoichiometry Why? Chemists are concerned with mass relationships in chemical reactions, usually run on a macroscopic scale (grams, kilograms, etc.). To deal with

More information

Chapter 2. Atoms and Elements

Chapter 2. Atoms and Elements Chapter 2. Atoms and Elements John Dalton Robert Millikan J.J. Thomson Ernest Rutherford The Components of Matter Elements, Compounds, Mixtures Dalton s Atomic Theory Modern Atomic Theory Atomic and Mass

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

Chemical Proportions in Compounds

Chemical Proportions in Compounds Chapter 6 Chemical Proportions in Compounds Solutions for Practice Problems Student Textbook page 201 1. Problem A sample of a compound is analyzed and found to contain 0.90 g of calcium and 1.60 g of

More 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

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

Chemical formulae are used as shorthand to indicate how many atoms of one element combine with another element to form a compound.

Chemical formulae are used as shorthand to indicate how many atoms of one element combine with another element to form a compound. 29 Chemical Formulae Chemical formulae are used as shorthand to indicate how many atoms of one element combine with another element to form a compound. C 2 H 6, 2 atoms of carbon combine with 6 atoms of

More information

The Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon-12? Molar Mass of Atoms 3/1/2015

The Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon-12? Molar Mass of Atoms 3/1/2015 The Mole Chapter 10 1 Objectives Use the mole and molar mass to make conversions among moles, mass, and number of particles Determine the percent composition of the components of a compound Calculate empirical

More 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

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

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

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

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

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

MOLES, MOLECULES, FORMULAS. Part I: What Is a Mole And Why Are Chemists Interested in It?

MOLES, MOLECULES, FORMULAS. Part I: What Is a Mole And Why Are Chemists Interested in It? NAME PARTNERS SECTION DATE_ MOLES, MOLECULES, FORMULAS This activity is designed to introduce a convenient unit used by chemists and to illustrate uses of the unit. Part I: What Is a Mole And Why Are Chemists

More information

A 1.008 g sample of H contains 6.0221415 x 10 23 H atoms.

A 1.008 g sample of H contains 6.0221415 x 10 23 H atoms. 7 Chemical Composition 7. Avogadro s umber n 8, the talian scientist, Amadeo Avogadro proposed that: Equal volumes of gas at equal temperatures and pressures have the same number of particles. This law,

More information

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

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

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

Chapter 1: Moles and equations. Learning outcomes. you should be able to:

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

More information

1) Scientific law = a generalization of scientific observations that describes what happens (does not explain)

1) Scientific law = a generalization of scientific observations that describes what happens (does not explain) I. Law vs. Theory 1) Scientific law = a generalization of scientific observations that describes what happens (does not explain) 2) Theory (model) = a set of assumptions used to explain observations and

More information

U3-LM2B-WS Molar Mass and Conversions

U3-LM2B-WS Molar Mass and Conversions U3-LM2B-WS Molar Mass and Conversions Name: KEY 1. The molar mass of chlorine is: 2 x 35.45 g/mol Cl = 70.90 g/mol Cl 2 (Remember that chlorine exists as a diatomic molecule in nature) 2. The molar mass

More information

4.4 Calculations Involving the Mole Concept

4.4 Calculations Involving the Mole Concept 44 Section 43 Questions 1 Define Avogadro s constant, and explain its significance in quantitative analysis 2 Distinguish between the terms atomic mass and molar mass 3 Calculate the mass of a molecule

More information

Chapter 3 Mass Relationships in Chemical Reactions

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

More information

TOPIC 7. CHEMICAL CALCULATIONS I - atomic and formula weights.

TOPIC 7. CHEMICAL CALCULATIONS I - atomic and formula weights. TOPIC 7. CHEMICAL CALCULATIONS I - atomic and formula weights. Atomic structure revisited. In Topic 2, atoms were described as ranging from the simplest atom, H, containing a single proton and usually

More information

MOLES AND MOLE CALCULATIONS

MOLES AND MOLE CALCULATIONS 35 MOLES ND MOLE CLCULTIONS INTRODUCTION The purpose of this section is to present some methods for calculating both how much of each reactant is used in a chemical reaction, and how much of each product

More information