A g sample of H contains x H atoms.


 Kelly Tucker
 4 years ago
 Views:
Transcription
1 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, known as Avogadro s Law, is one of the central ideas of chemistry. ne consequence of Avogadro s Law is that if a sample of an element has a mass in grams that equals the average atomic mass of the element, it will have 6.05 x 0 atoms of the element. The number, 6.05 x 0 is known as Avogadro s umber. Avogadro s umber refers to a package of particles known as a e (S unit: ) A 6.05 x 0 particles This is a kind of chemical packaging analogous to dozen refers to units. Just as you can refer to dozen eggs or dozen bags of popcorn, one can equally refer to of eggs or one e of bags of popcorn. n the latter cases the e of eggs or of bags of popcorn refer to 6.05 x 0 individual eggs or 6.05 x 0 individual bags of popcorn. The importance of Avogadro s umber is that it relates a unit mass of chemical to the number of particles of that particular chemical. n terms of atoms, one e of atoms is obtained when we weigh out exactly the average mass of the atom given in the Periodic Table, in units of grams. n other words, the number of particles in a sample can be indirectly counted by weighing out the sample. Thus, for example in the case of hydrogen, H.008 A.008 g sample of H contains 6.05 x 0 H atoms. Example: (the masses of the elements below are obtained from the Periodic Table) A sample of.0 g C contains 6.0 x 0 C atoms C atoms. A sample of 6.98 g Al contains 6.0 x 0 Al atom Al atoms. A sample of g Au contains 6.0 x 0 Au atoms Au atoms. A sample of 6.00 g contains 6.0 x 0 atoms atoms. Using Avogadro s umber, we can calculate the number of particles, and es, contained in any mass of chemical using the technique of dimensional analysis. Example:. Calculate the number of es of atoms and the number of atoms in a 3.75 g sample of carbon. C n 3.75 g C 0.33 C C.0 gc atoms C 0.33 C atoms C C C f course, if the question simply asked for the number of Carbon atoms, we could simply combine the steps: C atoms C 3.75 g C atoms C C.0 gc C page 55
2 . Calculate the number of es of atoms and the number of atoms in a 3.75 g sample of aluminum. Al n 3.75 g Al Al Al g Al atoms Al Al atoms Al Al Al or Al atoms Al 3.75 g Al atoms Al Al g Al Al 3. Calculate the number of es of atoms and the number of atoms in a 3.75 g sample of gold. Au n 3.75 gau Au Au gau atoms Au Au.70 0 atoms Au Au Au or Au atoms Au 3.75 g Au.70 0 atoms Au Au g Au Au The main point with all this is that the same mass of different materials will have different numbers of es (and particles). By knowing the mass of the particular substance, we can calculate the number of particles present. mass es particles Through Avogadro s umber and knowing the unit mass of a substance, can count the number of particles by weighing. Care must be taken however, to know exactly the type of substance we are dealing with. For example, a sample of 6.00 g contains 6.0 x 0 oxygenatoms but only 3.0 x 0 oxygenecules. This is because the oxygenecule is diatomic, that is, it consists of oxygenatoms g F H G g F g H G g atoms KJ F H G atoms K J atoms ecule KJ F H G atoms K J F H G atoms K J atoms ecules The second calculation can be done by using the packaging of es of atoms in es of ecules. F 600. g H G g KJ F H G K J F HG ecules KJ ecules page 56
3 7. Molecular Mass We have seen that we can count the number of atoms and ecules present in an element by weighing out a sample of the element and using Avogadro s umber to convert the mass to the number of atoms and ecules. The question is can we do the same when we have a ecule rather than an element? The answer is yes and this is demonstrated in the following examples. Examples:. What is the unit mass of carbon monoxide, C? Carbon monoxide consists of one atom of carbon and one atom of oxygen. Thus its mass is the sum of the masses of its component atoms. Unit mass of C.0 amu C amu 8.0 amu C Molecular Mass sum of the masses of the individual atoms This unit mass of C is known as the ecular mass (or ar mass) of C.. What is the ecular mass of methane, CH? From the Periodic Table, the atomic mass of C is.0 and of H is.008. The Molecular Mass of CH is: atom C F. 0 amu C 008. amu H atoms H HG atom C K J F + H G atom C K J. 3. What is the ecular mass of aluminum oxide, Al 3? From the Periodic Table, the atomic mass of Al is 6.98 and of H is The Molecular Mass of Al 3 is: atom Al F amu Al amu 3 atoms HG atom Al K J F + H G atom K J amu CH 096 amu Al3. What is the ecular mass of iron () sulphate, FeS? From the Periodic Table, the atomic mass of Fe is 55.85, S is 3.07 and is atom Fe F amu Al amu S amu atom S atom HG atom Al K J F + H G atom S K J F + H G atom K J. 5. What is the ecular mass of ammonium phosphate, (H ) 3 P? From the Periodic Table, the atomic mass of: H P amu FeS page 57
4 There are two main ways to go about calculating the ar mass of ionic compounds such as ammonium phosphate. i) Ammonium phosphate consists of 3 atoms, atoms H, atom P and atoms..007 amu.008 amu H amu P 6.00 amu 3 atoms + atoms H + atom P + atoms 9.09 amu ( H ) P 3 atom atom H atom P atom ii) An alternative is to calculate the mass of the individual ions and put them together in the ecule amu.008 amu H + Mass of H atom atoms H amu H atom atom H amu P 6.00 amu 3 Mass of P atom P atoms 9.97 amu P + atom P atom amu H amu P Molecular Mass ( H ) P 3 ions H 9.09 ( ) 3 ion P amu H P ion H ion P nce we have calculated the ecular mass (sometimes referred to as the ar mass) of a compound we may calculate the number of ecules in a given sample of the compound. Examples:. Calculate the number of ecules of FeS in a.37 g sample of FeS. The ar mass of FeS is 5.9. FeS ecules.37 g FeS ecules FeS FeS 5.9 g FeS. Calculate the number of ecules of (H ) 3 P in a.7 g sample of (H ) 3 P. ( H ) P ecules g H P ecules H P.7 ( H) 3P ( ) g ( H ) P 3 ( ) 3 We can also calculate the number of atoms and ecules of the elements that made up the compound. Examples:. Calculate the number of each type of atom in a 8.5 g sample of FeS. FeS n 8.5 gfes FeS FeS 5.9 gfes Fe FeS.6 0 Fe atoms Fe FeS S atoms S atoms FeS.6 0 FeS atoms FeS.58 0 atoms FeS atoms S page 58
5 . Calculate the number of each type of ecule of the element in a 8.5 g sample of FeS. FeS n 8.5 g FeS FeS FeS 5.9 gfes Fe FeS.6 0 Fe ecule Fe FeS S ecule S ecule FeS.6 0 FeS ecule FeS.9 0 ecule FeS ecule S ote that the elemental form of sulphur is S 8 but usually the monatomic form is used for simplicity. We can also calculate the mass of atoms and ecules of the elements that made up the compound. Example: Calculate the mass of each type of atom in a 8.5 g sample of FeS. FeS n 8.5 g FeS FeS FeS 5.9 gfes Fe g Fe m FeS g Fe Fe FeS Fe m FeS S FeS S g S gs S 6.00 g m FeS.85 g FeS 7.3 Percent Composition of Compounds So far the formulas of compounds have been expressed in terms of counting the atoms present in the ecule, i.e., the compounds sodium hydrogen phosphate, a HP, consists of atoms sodium, atom each hydrogen and phosphorus and atoms of oxygen. There is an older method of expressing the composition of compounds, one that predates the discovery of atoms. This method expresses the composition of compounds through the relative mass of each of the elements in the compound. The traditional way is to express the composition as a mass percentage of each component. mass of element in the compound % mass 00% total mass of the compound page 59
6 Example: Calculate the % mass of each element in sodium hydrogen phosphate, a HP. Mass of a x Mass of H x Mass of P x Mass of x Molar mass of a HP % mass a 00% 3.39% % mass H 00% 0.700% % mass P 00%.89% % mass 00% 5.08%.96 ote that % mass total % mass a + % mass H + % mass P+ % mass 3.39%+0.700%+.89%+5.08% 00.0% Example: Calculate the % mass of each element in glucose, C 6 H 6. Mass of C 6 x Mass of H x Mass of 6 x Molar mass of C 6 H % mass C 00% 0.000% % mass H 00% 6.76% % mass 00% 53.8% 80.7 To two decimal places, the total % mass sums to 00.00% as it should. ote that the mass percent of each element in a given compound is always constant, regardless of the actual mass of the sample. Thus, for example, a g sample of glucose will still consist of 0.000%C, 6.76%H and 53.8%. This fact can be used (if the % composition is known) to calculate the mass of elements that make up a particular compound of any sample size. page 60
7 Example: A sample of an organic compound has a mass of 7.9 mg. f the compound has a composition of 37.0%C,.%H,.% and 8.%, calculate the mass of each element in the sample gc mc 7.9 m 7.5 mg C gh m 7.9 m.05 mg H H g m 7.9 m 0. mg g m 7.9 m 8.70 mg Check: mg C mg H mg mg m + + +, which is correct within the limits of significant figures. page 6
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 informationStudy 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 informationChemical 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 informationHow 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 informationThe Mole Concept. The Mole. Masses of molecules
The Mole Concept Ron Robertson r2 c:\files\courses\111020\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 informationA 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 informationThe Mole Concept and Atoms
Copyright The McGrawHill 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 informationCHAPTER 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 informationWe 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 informationChapter 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 McGrawHill Companies,
More informationMole Calculations Multiple Choice Review PSI Chemistry
Mole Calculations Multiple Choice Review PSI Chemistry Name The Mole and Avogadro's Number 1)What is the SI unit for measurement of number of particles in a substance? A) kilogram B) ampere C) candela
More information602X10 21 602,000,000,000, 000,000,000,000 6.02X10 23. Pre AP Chemistry Chemical Quan44es: The Mole. Diatomic Elements
Pre AP Chemistry Chemical Quan44es: The Mole Mole SI unit of measurement that measures the amount of substance. A substance exists as representa9ve par9cles. Representa9ve par9cles can be atoms, molecules,
More informationName 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 informationHonors Chemistry: Unit 6 Test Stoichiometry PRACTICE TEST ANSWER KEY Page 1. A chemical equation. (C4.4)
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 informationPart 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 informationCh. 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 informationMolecules, Atoms, Grams and Mole Calculation Practice
Molecules, Atoms, Grams and Mole Calculation Practice Helpful HINTS: In these problems look for two things: 1) From what unit to what unit? 2) Does the object stay the same, or does the object change?
More informationUnit 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 informationChemistry 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 informationCalculating 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 informationMatter. 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 informationThe 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 informationATOMS. Multiple Choice Questions
Chapter 3 ATOMS AND MOLECULES Multiple Choice Questions 1. Which of the following correctly represents 360 g of water? (i) 2 moles of H 2 0 (ii) 20 moles of water (iii) 6.022 10 23 molecules of water (iv)
More informationUnit 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 informationCHAPTER 8: CHEMICAL COMPOSITION
CHAPTER 8: CHEMICAL COMPOSITION Active Learning: 14, 68, 12, 1825; EndofChapter Problems: 34, 982, 8485, 8792, 94104, 107109, 111, 113, 119, 125126 8.2 ATOMIC MASSES: COUNTING ATOMS BY WEIGHING
More informationElement 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 carbon12, 6p + + 6n 0 = atomic mass of 12.0 o For chlorine35, 17p + + 18n 0 = atomic mass of 35.0 atomic mass
More informationChapter 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 information2 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 informationChapter 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 informationMOLES 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= 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 informationCHEM 120 Online: Chapter 6 Sample problems Date: 2. Which of the following compounds has the largest formula mass? A) H2O B) NH3 C) CO D) BeH2
CHEM 120 Online: Chapter 6 Sample problems Date: 1. To determine the formula mass of a compound you should A) add up the atomic masses of all the atoms present. B) add up the atomic masses of all the atoms
More information1. 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 1024 g B. We need a conversion to the macroscopic world. 1. How many hydrogen atoms are in 1.00 g of hydrogen?
More informationWoods Chem1 Lec02 101 Atoms, Ions, Mole (std) Page 1 ATOMIC THEORY, MOLECULES, & IONS
Woods Chem1 Lec02 101 Atoms, Ions, Mole (std) Page 1 ATOMIC THEORY, MOLECULES, & IONS Proton: A positively charged particle in the nucleus Atomic Number: We differentiate all elements by their number
More informationMultiple Choice Identify the letter of the choice that best completes the statement or answers the question.
Introduction to Chemistry Exam 2 Practice Problems 1 Multiple Choice Identify the letter of the choice that best completes the statement or answers the question. 1.Atoms consist principally of what three
More informationThe Mole. Chapter 10. Dimensional Analysis. The Mole. How much mass is in one atom of carbon12? 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 informationFormulas, 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 informationMOLAR 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 informationLecture 3: (Lec3A) Atomic Theory
Lecture 3: (Lec3A) Atomic Theory Mass of Atoms Sections (Zumdahl 6 th Edition) 3.13.4 The Concept of the Mole Outline: The mass of a mole of atoms and the mass of a mole of molecules The composition of
More informationBalance 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 informationCh. 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 informationThe 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 informationThe 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 informationCalculation of Molar Masses. Molar Mass. Solutions. Solutions
Molar Mass Molar mass = Mass in grams of one mole of any element, numerically equal to its atomic weight Molar mass of molecules can be determined from the chemical formula and molar masses of elements
More informationb. 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 informationChemical 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 informationMOLECULAR 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 informationChapter 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 informationChemical 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 information3.3 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 informationName 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 informationCalculations and Chemical Equations. Example: Hydrogen atomic weight = 1.008 amu Carbon atomic weight = 12.001 amu
Calculations and Chemical Equations Atomic mass: Mass of an atom of an element, expressed in atomic mass units Atomic mass unit (amu): 1.661 x 1024 g Atomic weight: Average mass of all isotopes of a given
More informationMoles, 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 informationMole 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 informationF321 MOLES. Example If 1 atom has a mass of 1.241 x 1023 g 1 mole of atoms will have a mass of 1.241 x 1023 g x 6.02 x 10 23 = 7.
Moles 1 MOLES The mole the standard unit of amount of a substance (mol) the number of particles in a mole is known as Avogadro s constant (N A ) Avogadro s constant has a value of 6.02 x 10 23 mol 1.
More informationLecture 5, The Mole. What is a mole?
Lecture 5, The Mole What is a mole? Moles Atomic mass unit and the mole amu definition: 12 C = 12 amu. The atomic mass unit is defined this way. 1 amu = 1.6605 x 1024 g How many 12 C atoms weigh 12 g?
More informationConcept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects.
Chapter 3. Stoichiometry: MoleMass Relationships in Chemical Reactions Concept 1. The meaning and usefulness of the mole The mole (or mol) represents a certain number of objects. SI def.: the amount of
More informationIB Chemistry 1 Mole. One atom of C12 has a mass of 12 amu. One mole of C12 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 carbon12 that were needed to make 12 g of carbon. 1 mole
More informationChapter 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 informationSimple vs. True. Simple vs. True. Calculating Empirical and Molecular Formulas
Calculating Empirical and Molecular Formulas Formula writing is a key component for success in chemistry. How do scientists really know what the true formula for a compound might be? In this lesson we
More informationChapter 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 informationMoles 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 informationAS1 MOLES. oxygen molecules have the formula O 2 the relative mass will be 2 x 16 = 32 so the molar mass will be 32g mol 1
Moles 1 MOLES The mole the standard unit of amount of a substance the number of particles in a mole is known as Avogadro s constant (L) Avogadro s constant has a value of 6.023 x 10 23 mol 1. Example
More informationChapter 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 informationMultiple Choice questions (one answer correct)
Mole Concept Multiple Choice questions (one answer correct) (1) Avogadro s number represents the number of atoms in (a) 12g of C 12 (b) 320g of sulphur (c) 32g of oxygen (d) 12.7g of iodine (2) The number
More informationMoles. Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations
Moles Balanced chemical equations Molar ratios Mass Composition Empirical and Molecular Mass Predicting Quantities Equations Micro World atoms & molecules Macro World grams Atomic mass is the mass of an
More informationType: Single Date: Kinetic Theory of Gases. Homework: Read (14.1), Do CONCEPT Q. # (1), Do PROBLEMS # (2, 3, 5) Ch. 14
Type: Single Date: Objective: Kinetic Theory of Gases Homework: Read (14.1), Do CONCEPT Q. # (1), Do PROBLEMS # (2, 3, 5) Ch. 14 AP Physics Mr. Mirro Kinetic Theory of Gases Date Unlike the condensed phases
More informationName: Section: Calculating Dozens
Name: Section: The Mole This lesson is an introduction to the concept of the Mole and calculating conversions related to the Mole. The best analogy for understanding a mole is the dozen. A dozen is simply
More informationSample Exercise 3.1 Interpreting and Balancing Chemical Equations
Sample Exercise 3.1 Interpreting and Balancing Chemical Equations The following diagram represents a chemical reaction in which the red spheres are oxygen atoms and the blue spheres are nitrogen atoms.
More informationUnit 6 The Mole Concept
Chemistry Form 3 Page 62 Ms. R. Buttigieg Unit 6 The Mole Concept See Chemistry for You Chapter 28 pg. 352363 See GCSE Chemistry Chapter 5 pg. 7079 6.1 Relative atomic mass. The relative atomic mass
More informationAmount of Substance. http://www.avogadro.co.uk/definitions/elemcompmix.htm
Page 1 of 14 Amount of Substance Key terms in this chapter are: Element Compound Mixture Atom Molecule Ion Relative Atomic Mass Avogadro constant Mole Isotope Relative Isotopic Mass Relative Molecular
More informationAtomic Mass/Molar Mass, Percent Composition, & Empirical and Molecular Formula
Name AP Chemistry Atomic Mass/Molar Mass, Percent Composition, & Empirical and Molecular Formula Atomic Mass/Molar Mass The mass for an element reported on the Periodic Table is the average mass of all
More informationChapter 5 Chemical Quantities and Reactions. Collection Terms. 5.1 The Mole. A Mole of a Compound. A Mole of Atoms.
Chapter 5 Chemical Quantities and Reactions 5.1 The Mole 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 1
More informationChemistry 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 informationChemistry PostEnrolment Worksheet
Name: Chemistry PostEnrolment 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 informationWhat 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 informationW1 WORKSHOP ON STOICHIOMETRY
INTRODUCTION W1 WORKSHOP ON STOICHIOMETRY These notes and exercises are designed to introduce you to the basic concepts required to understand a chemical formula or equation. Relative atomic masses of
More informationWRITING CHEMICAL FORMULA
WRITING CHEMICAL FORMULA For ionic compounds, the chemical formula must be worked out. You will no longer have the list of ions in the exam (like at GCSE). Instead you must learn some and work out others.
More information10 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 informationChemical 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 informationChapter 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 informationPeriodic Table, Valency and Formula
Periodic Table, Valency and Formula Origins of the Periodic Table Mendelѐѐv in 1869 proposed that a relationship existed between the chemical properties of elements and their atomic masses. He noticed
More informationTuesday, 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 informationChapter 5, Calculations and the Chemical Equation
1. How many iron atoms are present in one mole of iron? Ans. 6.02 1023 atoms 2. How many grams of sulfur are found in 0.150 mol of sulfur? [Use atomic weight: S, 32.06 amu] Ans. 4.81 g 3. How many moles
More information19.2 Chemical Formulas
In the previous section, you learned how and why atoms form chemical bonds with one another. You also know that atoms combine in certain ratios with other atoms. These ratios determine the chemical formula
More informationU3LM2BWS Molar Mass and Conversions
U3LM2BWS 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 informationPOGIL Lesson Plan. Author: Sui Sum Olson. Title: Understanding the Mole and Molar Mass Concepts
POGIL Lesson Plan Author: Sui Sum Olson Title: Understanding the Mole and Molar Mass Concepts Subject Area(s): Chemistry 1, Honors Chemistry 1 Grades: 10 Description of Lesson: The Mole concept is fundamental
More informationAtomic 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 informationMolar 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 informationCH3 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 informationFormulae, stoichiometry and the mole concept
3 Formulae, stoichiometry and the mole concept Content 3.1 Symbols, Formulae and Chemical equations 3.2 Concept of Relative Mass 3.3 Mole Concept and Stoichiometry Learning Outcomes Candidates should be
More information12.011. 5.1: Atomic Mass Unit. 5.1: Atomic Mass  Natural Abundance. 5.1: Atomic Mass  Relative Abundance. 5.1: Average Atomic Mass
Topic 5: Stoichiometry  Chemical Arithmetic 5.: Atomic Mass Unit Masses of some atoms: H =.73 024 8 O = 2.788 023 Atomic Mass is defined relative to Carbon 2 isotope 2 2 amu is the mass of the C isotope
More informationMOLES, 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 informationChapter 3 Stoichiometry
Chapter 3 Stoichiometry 31 Chapter 3 Stoichiometry In This Chapter As you have learned in previous chapters, much of chemistry involves using macroscopic measurements to deduce what happens between atoms
More information5.1: Atomic Mass Unit
Topic 5: Stoichiometry  Chemical Arithmetic Masses of some atoms: H =.6736 024 6 8 O = 2.6788 023 92 U = 3.985 0 23822 Introducin.the Atomic Mass Unit (amu) amu =.66054 x 024 5.: Atomic Mass Unit
More information2014 Spring CHEM101 Ch12 Review Worksheet Modified by Dr. ChengYu Lai,
Ch1 1) Which of the following underlined items is not an intensive property? A) A chemical reaction requires 3.00 g of oxygen. B) The density of helium at 25 C is 1.64 104 g/cm3. C) The melting point
More informationChem 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 information2. ATOMIC, MOLECULAR AND EQUIVALENT MASSES
2. ATOMIC, MOLECULAR AND EQUIVALENT MASSES INTRODUCTION: EQUIVALENT WEIGHT Since hydrogen is the lightest of all elements, it was chosen as a standard for determination of equivalent weights. On this basis,
More informationDescription 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 informationStoichiometry of Formulas and Equations
sil07204_ch03_69107 8/22/05 15:16 Page 69 CHAPTER THREE Stoichiometry of Formulas and Equations Key Principles The mole (mol) is the standard unit for amount of substance and consists of Avogadro s number
More information