1 Example Exercise 9.1 Atomic Mass and Avogadro s Number Refer to the atomic masses in the periodic table inside the front cover of this textbook. State the mass of Avogadro s number of atoms for each of the following elements: (a) Copper (c) sulfur (b) Mercury (d) helium The atomic mass of each element is listed below the symbol of the element in the periodic table: Cu = amu, Hg = amu, S = amu, and He = 4.00 amu. The mass of Avogadro s number of atoms is the atomic mass expressed in grams. Therefore, atoms of (a) Cu = g (c) S = g (b) Hg = g (d) He = 4.00 g Refer to the periodic table and state the mass for each of the following: (a) 1 atom of Au (b) atoms of Au Answers: (a) amu; (b) g What is the mass of an average platinum atom? What is the mass of Avogadro s number of Pt atoms?
2 Example Exercise 9.2 Mole Calculations I Calculate the number of sodium atoms in mol Na. Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? Since 1 mol Na = atoms Na, the two unit factors are 1 mol Na/ atoms Na, and its reciprocal atoms Na/1 mol Na. Unit Analysis Map
3 Example Exercise 9.2 Continued Mole Calculations I We apply the unit factor atoms Na/1 mol Na to cancel moles denominator., which appears in the The answer is rounded to three digits because the given value and unit factor each have three significant digits. Calculate the number of formula units in mol of sodium chloride, NaCl. Answers: formula units NaCl What is the number of molecules in 1.00 mol of any gas?
4 Example Exercise 9.3 Mole Calculations I Calculate the number of moles of potassium in atoms K. Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? Since mol K = atoms K, the two unit factors are 1 mol K/ atoms K, and its reciprocal atoms K/1 mol K. Unit Analysis Map
5 Example Exercise 9.3 Continued Mole Calculations I We apply the unit factor 1 mol K/ atoms K to cancel atoms denominator., which appears in the The answer is rounded to three digits because the given value and unit factor each have three significant digits. Calculate the number of moles of potassium iodide in formula units of KI. Answer: 88.7 mol KI What is the number of molecules in 1.00 mol of iodine crystals?
6 Example Exercise 9.4 Molar Mass Calculations Calculate the molar mass for each of the following substances: (a) silver metal, Ag (b) ammonia gas, NH 3 (c) magnesium nitrate, Mg(NO 3 ) 2 We begin by finding the atomic mass of each element in the periodic table. The molar mass equals the sum of the atomic masses expressed in g/mol. (a) The atomic mass of Ag is amu, and the molar mass of silver equals g/mol. (b) The sum of the atomic masses for NH 3 is amu + 3(1.01)amu = amu. The molar mass of ammonia equals g/mol. (c) The sum of the atomic masses for Mg(NO 3 ) 2 is amu + 2( )amu = amu. The molar mass of magnesium nitrate equals g/mol. Calculate the molar mass for each of the following substances: (a) manganese metal, Mn (b) sulfur hexafluoride, SF 6 (c) strontium acetate, Sr(C 2 H 3 O 2 ) 2 Answers: (a) g/mol; (b) g/mol; (c) g/mol The molecular mass of water is amu. What is the mass of Avogadro s number of water molecules?
7 Example Exercise 9.5 Mole Calculations II What is the mass in grams of atoms of sulfur? Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? By definition, 1 mol S = atoms S, and the molar mass from the periodic table is g S = 1 mol S; the two pairs of unit factors are shown in Step 3. Unit Analysis Map
8 Example Exercise 9.5 Continued Mole Calculations II We apply the unit factor 1 mol S/ atoms S to cancel atoms S cancel mol S :, and g S/1 mol S to What is the mass of formula units of lead(ii) sulfide, PbS? Answer: 30.8 g PbS Sulfur occurs naturally as S 8 molecules. What is the mass of Avogadro s number of S 8 molecules?
9 Example Exercise 9.6 Mole Calculations II How many O 2 molecules are present in g of oxygen gas? Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? The molar mass from the periodic table is g O 2 = 1 mol O 2, and by definition, 1 mol O 2 = molecules O 2. Thus, the two pairs of unit factors are shown in Step 3. Unit Analysis Map
10 Example Exercise 9.6 Continued Mole Calculations II We apply the unit factor 1 mol O 2 /32.00 g O 2 to cancel g O 2 cancel moles O 2. Thus,, and molecules O 2 /1 mol O 2 to How many formula units of lithium fluoride are found in g LiF? Answer: formula units LiF Ozone occurs naturally as O 3 molecules. What is the mass of Avogadro s number of ozone molecules?
11 Example Exercise 9.7 Mass of a Molecule Calculate the mass in grams for a single molecule of carbon dioxide, CO 2 (given that MM = g/mol). Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? By definition, 1 mol CO 2 = molecules. Thus, the unit factors are shown in Step 3. Unit Analysis Map
12 Example Exercise 9.7 Continued Mass of a Molecule We apply the unit factor 1 mol CO 2 / molecules CO 2 to cancel mol CO 2. Calculate the mass in grams for a single molecule of carbon monoxide, CO. Answer: g/molecule What is the mass of a carbon monoxide molecule expressed in amu?
13 Example Exercise 9.8 Density of a Gas at STP Calculate the density of ammonia gas, NH 3, at STP. (MM = g/mol) Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? From the molar volume of a gas at STP, 1 mol = 22.4 L; thus, the unit factors are 1 mol/22.4 L, and 22.4 L/1 mol. Unit Analysis Map
14 Example Exercise 9.8 Continued Density of a Gas at STP We apply the unit factor 1 mol /22.4 L to cancel moles the denominator., which appears in If we filled a balloon with ammonia gas (0.761 g/l), the balloon would float in air (1.29 g/l). Similarly, a less dense liquid floats on a more dense liquid; for example, gasoline (0.7 g/ml) floats on water (1.0 g/ml). Calculate the density of hydrogen sulfide gas, H 2 S, at STP. Answer: 1.52 g/l Why does the balloon filled with helium gas rise, while the balloon filled with nitrogen gas does not?
15 Example Exercise 9.9 Molar Mass of a Gas A fire extinguisher releases 1.96 g of an unknown gas that occupies 1.00 L at STP. What is the molar mass (g/mol) of the unknown gas? Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? From the molar volume of a gas at STP, 1 mol = 22.4 L; thus, the unit factors are 1 mol/22.4 L, and 22.4 L/1 mol. Unit Analysis Map
16 Example Exercise 9.9 Continued Molar Mass of a Gas We apply the unit factor 1 mol/22.4 L to cancel liters, which appears in the denominator. Because the unknown gas is from a fire extinguisher, we suspect that it is carbon dioxide. By summing the molar mass for CO 2 (44.01 g/mol), we help confirm that the unknown gas is carbon dioxide. Boron trifluoride gas is used in the manufacture of computer chips. Given that g of the gas occupies 497 ml at STP, what is the molar mass of boron fluoride gas? Answer: 67.8 g/mol What is the volume of one mole of any gas at STP?
17 Example Exercise 9.10 Mole Calculations III What is the mass of 3.36 L of ozone gas, O3, at STP? Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? From the molar volume of a gas at STP, 1 mol O 3 = 22.4 L O 3. The molar mass from the periodic table is g O 3 = 1 mol O 3. Thus, the two pairs of unit factors are shown in Step 3. Unit Analysis Map
18 Example Exercise 9.10 Mole Calculations III Continued We apply the unit factor 1 mol O 3 /22.4 L O 3 to cancel L O 3 cancel moles O 3,, and g O 3 /1 mol O 3 to What volume is occupied by g of methane gas, CH 4, at STP? Answer: L CH 4 (174 ml) How many molecules of ozone are in one mole of gas?
19 Example Exercise 9.11 Mole Calculations III How many molecules of hydrogen gas, H 2, occupy L at STP? Strategy Plan Step 1: What unit is asked for in the answer? Step 2: What given value is related to the answer? Step 3: What unit factor(s) should we apply? From the molar volume of a gas at STP, 1 mol H 2 = 22.4 L H 2 and by definition, 1 mol H 2 = molecules H 2. Thus, the two pairs of unit factors are shown in Step 3. Unit Analysis Map
20 Example Exercise 9.11 Continued Mole Calculations III We apply the unit factor 1 mol H 2 /22.4 L H 2 to cancel L H 2, and molecules H 2 /1 mol H 2 to cancel moles 77H 2. Thus, What is the volume occupied by atoms of helium gas, He, at STP? Answer: L He (124 ml) What is the mass of one mole of hydrogen gas?
21 Example Exercise 9.12 Percent Composition of a Substance TNT (trinitrotoluene) is a white crystalline substance that explodes at 240 C. Calculate the percent composition of TNT, C 7 H 5 (NO 2 ) 3. Let s calculate the percent composition assuming there is 1 mol of TNT. For compounds with parentheses, it is necessary to count the number of atoms of each element carefully. That is, 1 mol of C 7 H 5 (NO 2 ) 3 contains 7 mol of C atoms, 5 mol of H atoms, 3 mol of NO 2 (that is, 3 mol N atoms and 6 mol of O atoms). We begin the calculation by finding the molar mass of C 7 H 5 (NO 2 ) 3 as follows: Now, let s compare the mass of each element to the total molar mass of the compound, that is, g. The percent composition of TNT reveals that the explosive is mostly oxygen by mass. When we sum the individual percentages ( = 99.99%), we verify our calculation and, find that the total is approximately 100%.
22 Example Exercise 9.12 Continued Percent Composition of a Substance EDTA (ethylenediaminetetraacetic acid) is used as a food preservative and in the treatment of metallic lead poisoning. Calculate the percent composition of EDTA, C 10 H 16 N 2 O 8. Answers: 41.09% C, 5.53% H, 9.587% N, and 43.79% O If an analysis of sugar, C x H y O z, gave 40.0% C and 6.7% H, what is the percent oxygen? Answers: See Appendix G.
23 Example Exercise 9.13 Empirical Formula from Mass Composition In a laboratory experiment, g of scandium was heated and allowed to react with oxygen from the air. The resulting product oxide had a mass of g. Now, let s find the empirical formula for scandium oxide, Sc? O?. The empirical formula is the simplest whole-number ratio of scandium and oxygen in the compound scandium oxide. This ratio is experimentally determined from the moles of each reactant. The moles of scandium are calculated as follows: The moles of oxygen are calculated after first subtracting the mass of Sc from the product, Sc? O? : The moles of oxygen are calculated from the mass of oxygen that reacted: The mole ratio in scandium oxide is Sc O To simplify the ratio and obtain small whole numbers, we divide by the smaller number: Since the calculated ratio is not close to whole numbers, we cannot round off the experimental ratio Sc 1.00 O However, we can double the ratio to obtain whole numbers, that is, Sc 2.00 O Thus, the empirical formula is Sc 2 O 3.
24 Example Exercise 9.13 Continued Empirical Formula from Mass Composition Iron can react with chlorine gas to give two different compounds, FeCl 2 and FeCl 3. If g of metallic iron reacts with chlorine gas to yield g of iron chloride, which iron compound is produced in the experiment? Answer: FeCl 3 If mol of yellow powder sulfur reacts with mol of oxygen gas, what is the empirical formula of the sulfur oxide?
25 Example Exercise 9.14 Empirical Formula from Percent Composition Glycine is an amino acid found in protein. An analysis of glycine gave the following data: 32.0% carbon, 6.7% hydrogen, 18.7% nitrogen, and 42.6% oxygen. Calculate the empirical formula of the amino acid. If we assume a 100 g sample, then the percentage of each element equals its mass in 100 g of glycine, that is, 32.0 g C, 6.7 g H, 18.7 g N, and 42.6 g O. We can determine the empirical formula as follows: The mole ratio of the elements in the amino acid is C 2.66 H 6.6 N 1.33 O We can find a small whole-number ratio by dividing by the smallest number: Simplifying, we find that the empirical formula for the amino acid glycine is C 2 H 5 NO 2.
26 Example Exercise 9.14 Continued Empirical Formula from Percent Composition Calculate the empirical formula for caffeine given the following percent composition: 49.5% C, 5.15% H, 28.9% N, and 16.5% O. Answer: C 4 H 5 N 2 O If mol of yellow powder sulfur reacts with mol of oxygen gas, what is the empirical formula of the sulfur oxide?
27 Example Exercise 9.15 Molecular Formula from Empirical Formula The empirical formula for fructose, or fruit sugar, is CH 2 O. If the molar mass of fructose is 180 g/mol, find the actual molecular formula for the sugar. We can indicate the molecular formula of fructose as (CH2O)n. The molar mass of the empirical formula CH 2 O is 12 g C + 2(1 g H) + 16 g O = 30 g/mol. Thus, the number of multiples of the empirical formula is Thus, the molecular formula of fructose is (CH 2 O) 6 or C 6 H 12 O 6. Ethylene dibromide was used as a grain pesticide until it was banned. Calculate (a) the empirical formula and (b) the molecular formula for ethylene dibromide given its approximate molar mass of 190 g/mol and its percent composition: 12.7% C, 2.1% H, and 85.1% Br. Answers: (a) CH 2 Br; (b) C 2 H 4 Br 2 If the molecular formula of hydrogen peroxide is H 2 O 2, what is the empirical formula?
INTRODUCTORY CHEMISTRY Concepts and Critical Thinking Sixth Edition by Charles H. Corwin Chapter 9 The Mole Concept by Christopher Hamaker 2011 Pearson Education, Inc. Chapter 9 1 Avogadro s Number Avogadro
Practice questions for Chapter 8 2) How many atoms of nickel equal a mass of 58.69 g? (Refer to the Periodic Table.) A) 1 B) 28 C) 58.69 D) 59 E) 6.02 x 1023 Answer: E Section: 8.1 Avogadro's Number 6)
CHEMICAL QUANTITIES Chapter 10 What is a mole? A unit of measurement in chemistry 1 mole of a substance = 6.02 x 10 23 (Avagadro s number) representative particles of a substance Representative particle
Chem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses B. Calculations of moles C. Calculations of number of atoms from moles/molar masses 1. Avagadro
MASS RELATIONS IN CHEMISTRY; STOICHIOMETRY [MH5; Ch. 3] Each element has its own unique mass. The mass of each element is found on the Periodic Table under the chemical symbol for the element (it is usually
Unit 6 Notepack: Chapters 9 &10 Chemical Quantities 9.1 Naming Ions NAME Period: A. ions: Ions made of single. B. Elements: There is a pattern in predicting how many electrons are lost and gained for the
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
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
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
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
Chem. I Notes Ch. 12, part 2 Using Moles NOTE: Vocabulary terms are in boldface and underlined. Supporting details are in italics. 1 MOLE = 6.02 x 10 23 representative particles (representative particles
CHAPTER THREE: CALCULATIONS WITH CHEMICAL FORMULAS AND EQUATIONS Part One: Mass and Moles of Substance A. Molecular Mass and Formula Mass. (Section 3.1) 1. Just as we can talk about mass of one atom of
Chapter 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
CHAPTER 3 STOICHIOMETRY OF FORMULAS AND EQUATIONS FOLLOW UP PROBLEMS 3.1A Plan: The mass of carbon must be changed from mg to g. The molar mass of carbon can then be used to determine the number of moles.
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
SCH 4C1 Unit 2 Problem Set Questions taken from Frank Mustoe et all, "Chemistry 11", McGraw-Hill Ryerson, 2001 1. A small pin contains 0.0178 mol of iron. How many atoms of iron are in the pin? 2. A sample
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
Chapter 3: Stoichiometry Goal is to understand and become proficient at working with: 1. Avogadro's Number, molar mass and converting between mass and moles (REVIEW). 2. empirical formulas from analysis.
Unit 9 Stoichiometry Notes (The Mole Continues) is a big word for a process that chemist s use to calculate amounts in reactions. It makes use of the coefficient ratio set up by balanced reaction equations
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.
Chapter 3. Stoichiometry: Mole-Mass Relationships in Chemical Reactions Concept 1. The meaning and usefulness of the mole The mole (or mol) represents a certain number of objects. SI def.: the amount of
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,
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
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
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
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
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 10-24 g How many 12 C atoms weigh 12 g?
Chapter 3 Formulas, Equations and Moles Interpreting Chemical Equations You can interpret a balanced chemical equation in many ways. On a microscopic level, two molecules of H 2 react with one molecule
Chapter 1 The Atomic Nature of Matter 6. Substances that cannot be decomposed into two or more simpler substances by chemical means are called a. pure substances. b. compounds. c. molecules. d. elements.
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?
1. Balance the following equation. What is the sum of the coefficients of the reactants and products? 1 Fe 2 O 3 (s) + _3 C(s) 2 Fe(s) + _3 CO(g) a) 5 b) 6 c) 7 d) 8 e) 9 2. Which of the following equations
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
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
Exercise #1 Atomic Masses 1. The average mass of pennies minted after 1982 is 2.50 g and the average mass of pennies minted before 1982 is 3.00 g. In a sample that contains 90.0% new and 10.0% old pennies,
TUTORIAL 5-1 HELP ANSWER TO QUESTION 1 ON TUTORIAL 5-1: Question 1. Find the percent composition by mass of sodium phosphate, Na 3 PO 4. Step 1: Find the molar mass of Na 3 PO 4 (The mass of one mole of
21 st Century Chemistry Multiple Choice Question in Topic 3 Metals Unit 11 1. Consider the equation: 2Ca(s) + O 2 (g) 2CaO(s) Which of the following statements are correct? (1) Calcium and oxygen are reactants.
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
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
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!
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
Section 6.6: The Composition of Unknown Compounds Tutorial 1 Practice, page 286 1. Given: = 4.60 g ; m N = 1.40 g Required: percentage of each element: % N; % O Step 1. Use the percentage formula to calculate
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
Teacher: Mr. gerraputa Print Close Name: 1. A chemical formula is an expression used to represent 1. mixtures, only 3. compounds, only 2. elements, only 4. compounds and elements 2. What is the total number
Chemical Quantities: The Mole Name Warm-Ups (Show your work for credit) Date 1. Date 2. Date 3. Date 4. Date 5. Date 6. Date 7. Date 8. Chemical Quantities: The Mole 2 Study Guide: Things You Must Know
Notes: Formula Mass and Percent Composition Formula mass - the mass of one mole of a compound, atom or ion. -also called: gram formula mass, molecular mass, gram molecular mass, formula weight, gram formula
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
Formula Conventions (1 of 24) Superscripts used to show the charges on ions Mg 2+ the 2 means a 2+ charge (lost 2 electrons) Subscripts used to show numbers of atoms in a formula unit H 2 SO 4 two H s,
The Mole and Chemical Table of Contents Chemical Formulas Bellringer List as many common counting units as you can. Determine how many groups of each unit in your list are present in each of the following
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.
Unit 9 Compounds Molecules INTRODUCTION Compounds are the results of combinations of elements. These new substances have unique properties compared to the elements that make them up. Compounds are by far
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
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
CHAPTER 7 Empirical Formulas Suppose you analyze an unknown compound that is a white powder and find that it is composed of 36.5% sodium, 38.1% oxygen, and 25.4% sulfur. You can use those percentages to
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
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
CHEM1001 2014-J-2 June 2014 22/01(a) What is the molarity of the solution formed when 0.50 g of aluminium fluoride is dissolved in 800.0 ml of water? 2 The molar mass of AlF 3 is: molar mass = (26.98 (Al)
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
Chapter 3 Stoichiometry of Formulas and Equations Chapter 3 Outline: Mole - Mass Relationships in Chemical Systems 3.1 The Mole 3.2 Determining the Formula of an Unknown Compound 3.3 Writing and Balancing
Woods Chem-1 Lec-02 10-1 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
Chapter 12 Exploring Gas Laws Solutions for Practice Problems Student Textbook page 477 1. Problem At 19 C and 100 kpa, 0.021 mol of oxygen gas, O 2(g), occupy a volume of 0.50 L. What is the molar volume
MODERN CHEMISTRY Date Name Period Multiple Choice - Identify the choice that best completes the statement or answers the question. Use answer-key worksheet (Page 6) to key in answers to questions. 1. A
Stoichiometry 1 The total number of moles represented by 20 grams of calcium carbonate is (1) 1; (2) 2; (3) 01; (4) 02 2 A 44 gram sample of a hydrate was heated until the water of hydration was driven
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
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
CHEMISTRY MOLE CONCEPT DALTON S ATOMIC THEORY By observing the laws of chemical combination, John Dalton proposed an atomic theory of matter. The main points of Dalton s atomic theory are as follows: (i)
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
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.
Chapter 4. The Mole Concept Introduction If you were to take one volume (Eg. 1cm 3 ) of every element, weigh them and rank them according to their weights you would discover that they followed the periodic
Chapter 3: Stoichiometry Mole - Mass Relationships in Chemical Systems 3.1 The Mole 3.2 Determining the Formula of an Unknown Compound 3.3 Writing and Balancing Chemical Equations 3.4 Calculating the Amounts
The Mole **Make sure you get your daily work signed off on. That way, when we test you'll have the grade you earned instead of Videos freaking out about 50's in the book. #1 -- The Mole #2 -- Particles