Amount of Substance.
|
|
- Kelly Davidson
- 8 years ago
- Views:
Transcription
1 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 Mass Relative Formula Mass Simple molecular structure Giant ionic structure Molecular formula Empirical formula Structural formula Structural Isomer Before starting, you must check up on elements, compounds and mixtures. Write some brief notes to outline these ideas. The following link will help you. Relative Atomic Mass and the Avogadro constant In this section you are going to learn: The meaning of the term relative atomic mass for elements containing atoms. The meaning of the term relative isotopic mass for elements with isotopes. That the relative atomic mass of an element when taken in grams is the mass of 1 mole of that element. About the Avogadro constant, its numerical value, the term 1 mol, and how these relate to elements. How to do simple calculations involving the mole. We start the topic Amount of Substance with a question Chemists don't deal with the masses of atoms and molecules measured in grams because they would be dealing with extremely small numbers. Instead, the masses of atoms and molecules are compared with that of the isotope carbon C is assigned a relative atomic mass of 12. As an example, consider an atom of magnesium. Two atoms of 12 C are required to be equal in mass to one atom of Mg therefore the relative atomic mass of Mg is 24. So, using the scales below, one atom of magnesium is balanced by two atoms of carbon-12. You should note that relative masses have no units because in their calculation the units have cancelled.
2 Page 2 of 14 Q1. Use a chemistry textbook or Periodic Table to look up the relative atomic mass of silver. Now draw in the correct number of carbon atoms needed to balance one atom of Ag. Study the information in the table below. It refers to the atoms of elements. Element Ca Na Pb Fe Cl H He Ag Relative Atomic Mass, Ar Mass of 1 mol g 23 g 207 g 56 g 35.5 g 1 g 4 g 108 g In each of the above masses of elements, there is the same number of atoms. That is, the relative atomic mass, Ar, of an element expressed in grams always contains the same number of atoms. This number can be determined experimentally. It is x The number is a constant, called the Avogadro constant, L (or N A ). The mass of this amount of atoms is called one mole (1 mol). Amedeo Avogadro was born in Turin, Italy, on 9th August It was in 1811 when he published his famous hypothesis, now called Avogadro's law. Avogadro died on the 9th July The postage stamp pictured was to remember Avogadro 100 years after his death. Avogadro's law is considered in a later part of this course. For an element with isotopes, the relative mass of the atoms of each of isotope of that element can be referred to as the relative isotopic mass. If an element has no isotopes then the term relative atomic mass is normally used. We will return to this idea in the next section. Note that chemists often use the term relative atomic mass when relative isotopic mass would be strictly more correct.
3 Page 3 of 14 Relative Molecular Mass - Elements and compounds consisting of molecules In this section you are going to learn: That a molecule is a group of two or more covalently bonded atoms. That some elements and some compounds consist of molecules. That the relative molecular mass of an element or compound when taken in grams is the mass of 1 mole of that substance. About the units of the Avogadro constant. How to do simple calculations involving the mole. Study the information in the table below. It refers to the molecules of elements and compounds. Element or compound Relative Molecular Mass, Mr Mass of 1 mol CO 2 SO 2 N 2 H 2 Cl 2 CH 4 H 2 O NH g 64 g 28 g 2 g 71 g 16 g 18 g 17 g A molecule is a group of two or more atoms that are bonded together by covalent bonding. A molecule is an entity in itself. A dot-cross diagram representing methane, CH 4, is represented below. The relative molecular mass, Mr, of an element or compound expressed in grams always contains the same number of molecules. Again, this number is the Avogadro Constant. The Avogadro constant has units Since the Avogadro Constant is the number of particles (atoms, molecules, ions) in 1 mole it has units they are mol -1 (particles mol -1, but the particles bit is omitted). The Avogadro Constant is x mol -1. Relative molecular mass, Mr, can be calculated by adding together the relative atomic masses of the constituent atoms, e.g. Mr (CO 2 ) = = 44.
4 Page 4 of 14 Q2. The relative molecular mass of water is 18. Complete the diagram below by balancing the number of water molecules against carbon atoms. Relative Formula Mass - Compounds consisting of ions (ionic compounds) In this section you are going to learn: That Sodium Chloride, NaCl, is an example of an ionic compound. It has a giant ionic lattice structure. The terms 'relative formula mass' and 'formula unit' as they apply to ionic compounds. What is meant by 1 mol of an ionic compound and how this relates to the amounts in moles of the ions it contains. How to do simple calculations involving the mole. Giant ionic lattice structure (for NaCl) means that in the crystal structure of sodium chloride each Na + ion is surrounded by six Cl - ions and each Cl - ion by six Na + ions. This arrangement of ions can in theory go on and on indefinitely. This is why the structure is referred to as 'giant'. It is represented below. You can read more about this at: Also, the structure is held together by electrostatic attractions between the oppositely charged ions. These are called ionic bonds. Sodium chloride therefore is not molecular, it is ionic. Also, the formula NaCl is an empirical formula (see later), and is sometimes called a formula unit. It is best to use the term relative formula mass (rather than relative molecular mass) for ionic compounds. For the formula unit Na + Cl - the relative formula mass is 23 +
5 Page 5 of = One mole of Na + Cl - is 58.5 g. This mass contains 1 mol (23 g) of Na + ions and 1 mol (35.5 g) of Cl - ions, that is, two moles of ions in total. Note that sometimes the term relative molecular mass is used to refer to ionic compounds. Q3. Work out the relative formula mass of FeSO 4,7H 2 O(s). Q4. What is the mass of 1 mole of iron(ii) sulphate(vi)-7-water? Q5. You have 2 moles of FeSO 4,7H 2 O. How many moles of each type of ion and molecule are present in this amount? Mole Calculations In this section you are going to learn: More about simple calculations involving the mole concept. Think about the above ideas and you should be able to calculate the amount in moles of a given mass of a substance, e.g g of Cl atoms is 1 mol g of Cl 2 molecules is ½ mole of Cl 2 molecules. If you are given the amount in moles, then multiplying this by the mass of one mole gives the amount in grams, e.g. 1½ mole of SO 2 is 1½ x 64 = 96 g. Q6. Calculate the mass in grams of ¾ mole of sulphuric(vi) acid, H 2 SO 4. Q7. You have 145 g of propanone, CH 3 COCH 3, what amount of this is there in moles?
6 Page 6 of 14 Balanced Chemical Equations In this section you are going to learn: That a balanced chemical equation gives information about the amounts of reactants that react and of products that form. How to do simple mole calculations involving chemical equations. Balanced chemical equations give information about the molar amounts of substances that react and the molar amounts of products that form. For example, 2Mg(s) + O 2 (g) 2MgO(s) The above equation tells us that 2 moles of magnesium atoms react with 1 mole of oxygen molecules to form 2 moles of magnesium oxide, an ionic compound. This means that, for example, 12 g (½ mole) Mg will require 8 g (¼ mole) of O 2 to react completely to form 20 g (½ mole) MgO. Q8. If g of magnesium metal is completely burned in excess oxygen, what mass of magnesium oxide is obtained? Q9. Some granulated zinc metal was added to an excess of a solution of hydrochloric acid. The zinc reacted completely and 4 g of hydrogen gas was formed. Calculate the mass of zinc in grams added to the acid.
7 Page 7 of 14 Chemical Formulae The meaning of empirical formula, molecular formula and structural formula and how these are related. About structural isomers and how to draw these for simple alkanes. This section refers to compounds that are molecular. With a little knowledge of organic chemistry you would know that C 4 H 10 is the formula for two alkanes. It tells us that in each of these there are four atoms of carbon and ten atoms of hydrogen bonded together. This type of formula is called a molecular formula. It gives the actual number of each type of atom in the molecule but does not tell you the arrangement in which they are bonded. The simplest whole-number ratio of C:H is 2:5. This gives the formula C 2 H 5, and it is called the empirical formula. (Remember that NaCl, for example, is an empirical formula because of the nature of its giant ionic lattice structure.) Q10. The molecular formula of glucose is C 6 H 12 O 6. What is its empirical formula? Q11. The molecular formula of sucrose is C 12 H 22 O 11. What is its empirical formula? So, the empirical formula of a covalent compound is the simplest whole-number ratio of atoms in its molecules. Or, you could say the simplest whole-number ratio of moles of atoms in 1 mole of the compound. If you know the empirical formula of a compound and also its relative molecular mass, then the molecular formula can be found. This is illustrated below. Q12. A hydrocarbon consists of 82.8% carbon and 17.2% hydrogen. Its relative molecular mass is 58. Calculate the empirical formula and the molecular formula of the compound.
8 Page 8 of 14 A structural formula shows the arrangement in which the atoms are bonded. For C 4 H 10 these are shown below and are referred to as structural isomers: Some additional questions for you to try An atom of titanium has four times the mass of an atom of 12 C. What is its relative atomic mass? 2. An atom of helium has one-third the mass of an atom of 12 C. What is its relative atomic mass? 3. A molecule of water has 1½ times the mass of an atom of 12 C. What is its relative molecular mass? 4. What mass of 12 C consists of x atoms? 5. The relative atomic mass of lead is 207. What is the molar mass (mass of 1 mole) of Pb? 6. What is the mass of 2 moles of molecules of ethanol, CH 3 CH 2 OH (Ar (H) = 1; Ar (C) = 12; Ar (O) = 16)? 7. What mass of sulphur contains the same number of atoms as there are present in 1.5 moles of magnesium (Ar (Mg) = 24; Ar (S) = 32)?
9 Page 9 of What mass of ammonia (NH 3 ) contains the same number of molecules as there are atoms present in 2 moles of sodium (Ar (H) = 1; Ar (N) = 14; Ar (Na) = 23)? 9. How many moles of oxygen are there in 128 g of O 2 (Ar (O) = 16)? 10. How many moles of sodium sulphate(vi), Na 2 SO 4, are contained in 71 g (Ar (O) = 16; Ar (Na) = 23; Ar (S) = 32)? 11. How many moles of Al 3+ are there in 2 moles Al 2 (SO 4 ) 3? 12. In the following reaction, what mass (in grams) of SO 2 (g) is formed when ½ mole of S reacts with oxygen (Ar (O) = 16; Ar (S) = 32;)? S(s) + O 2 (g) SO 2 (g) 13. In an experiment to find the formula of copper iodide, 0.17 g of Cu reacts with 0.34 g of iodine. What is the formula of copper iodide (Ar (Cu) = 63.55; Ar (I) = )?
10 Page 10 of In an experiment to find the formula of a lead oxide, g of the oxide, on reduction (removal of oxygen), gave g of Pb. What is the formula of the oxide (Ar (0) = 16; Ar (Pb) = 207)? 15. What is the percentage mass of S in SO 2 (Ar (O) = 16; Ar (S) = 32)? 16. What is the percentage mass of water of crystallisation (H 2 O) in FeSO 4.7H 2 O(s) (Ar (H) = 1; Ar (O) = 16; Ar (S) = 32; Ar (Fe) = 56)? &KHPLFDO,GHDVH[SODLQVKRZUHODWLYHPDVVHVRIDWRPVDQGPROHFXOHVFDQEHPHDVXUHGXVLQJD PDVVVSHFWURPHWHU,WDOVRPHQWLRQVLWVXVHLQWKHILQGLQJRXWDERXWWKHVWUXFWXUHRIPROHFXOHV The Mass Spectrometer In this section you are going to learn: How the mass spectrometer works. How relative isotopic mass and relative atomic mass are related, and how to calculate a relative atomic mass from mass spectral data. How the mass spectrometer is used in the analysis of molecular structure. The existence of isotopes of elements was discovered using an instrument called a mass spectrometer. The mass spectrometer was invented by the English physicist Francis William Aston ( ) when he was working in Cambridge with J. J. Thomson. Aston eventually discovered many of the naturally occurring isotopes of non-radioactive elements. He was awarded the Nobel Prize for Chemistry in 1922.
11 Page 11 of 14 Time-in-flight Mass Spectrometer,QWKLVVHFWLRQVRPHLGHDVDQGGLDJUDPVDUHDGDSWHGIURP KWWSZZZNRUHFRXNWXWRULDOKWP The following description of a time-of-flight mass spectrometer is very simplified. We assume all ions produced leave the source at the same time, with the same kinetic energy. A time-of-flight mass spectrometer identifies sample atoms (or molecules) by measuring their flight time. This diagram above shows the working principle of a linear time-of-flight mass spectrometer. It is necessary to put a charge on the atoms (or molecules) by bombarding them with electrons emitted from a filament. Each atom (or molecule) loses one electron to form an ion with a single positive charge. M(g) + e - M + (g) + 2e - The sample ions (M + ) are then accelerated by an electric field to give each of them the same kinetic energy. They then enter into a part of the mass spectrometer, called the flight path, which has no electric field. All of the ions travel the same distance through this part of the instrument to reach the ion detector. The speed of an ion is dependent upon its mass, with heavy ions having a lower velocity than light ones, and so the time it takes for an ion to reach the detector is related to its mass. The mass spectrometer measures the relative abundance (relative number) and relative mass of each type of ion reaching the detector. This data is represented as a mass spectrum. The mass of an atom or molecules is expressed relative to that of an atom of the isotope carbon-12 ( 12 C = 12).
12 Page 12 of 14 Where an element has two or more isotopes, the mass spectrometer measures the relative isotopic masses and their relative numbers (relative abundances) and plots a mass spectrum, as shown below. The relative isotopic mass of a chlorine atom is either 35 or 75. However, the relative atomic mass of chlorine is given as 35.5 in a chemical data book. This is because, for an element with isotopes, the relative atomic mass of an element takes into account the relative abundance and relative mass of each isotope present. In a typical sample of naturally occurring chlorine, 100 atoms will consist of 75 of relative mass 35 and 25 of relative mass 37. Using the mass spectrum on the left, the relative atomic mass of Cl is calculated as follows: Ar = (75/100 x 35) + (25/100 x 37) = 35.5 In the spectrum on the right, the most abundant isotope is assigned a relative abundance of 100% and each of the other isotopes is assigned a relative abundance relative to that. Q13. Use the mass spectrum on the right above to calculate the relative atomic mass, Ar, of chlorine. Q14. The mass spectrum of antimony shows it has two naturally occurring isotopes at relative mass 121 (relative abundance 57.3%) and relative mass 123 (relative abundance 42.7%) respectively. Draw a diagram to represent this mass spectrum and calculate the relative atomic mass, Ar, of antimony.
13 Page 13 of 14 The mass spectrometer in the analysis of molecular structure When the molecules of a substance enter the mass spectrometer to become ionised by loss of an electron, the 'molecular ion' (M + ) is formed. Some of these pass through the instrument and remain intact, to produce a peak in the mass spectrum at the relative molecular mass. Others are likely to fragment (break up) in various ways to produce smaller positively charge ions, which produce corresponding peaks in the mass spectrum. These numerous peaks can reveal how the atoms of the molecule were bonded together, that is its molecular structure. There is more about these ideas in a later module. Some additional questions about mass spectrometry This chapter provides some additional questions to help you assess your learning. When you have answered these and have checked your answers against the correct ones, refer to the table that follows to find out what you may need to do to further your progress. 1. An atom of titanium has four times the mass of an atom of 12 C. What is its relative atomic mass? 2. An atom of helium has one-third the mass of an atom of 12 C. What is its relative atomic mass? 3. Using a mass spectrometer, it is possible to determine the number of A protons in an atom. B energy levels in an atom. C atoms in 1 mole of an element. D isotopes of an element. E neutrons in an atom. 4. Iron has four isotopes with relative numbers of atoms as follows: 54 Fe (5.8%), 56 Fe (91.7%), 57 Fe (2.2%), 58 Fe (0.3%). Calculate the relative atomic mass of iron.
14 Page 14 of The mass spectrum for naturally-occurring magnesium is shown below. Singly charged Mg + ions have produced the peaks. What is the relative atomic mass of magnesium? A 24.2 B 24.3 C 24.4 D 24.7 E Which one of the following particles has seven protons, eight neutrons and nine electrons? A 7 8 N - B 7 14 N 2- C 7 15 N - D 8 15 N 2- E 7 15 N 2-
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 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. 352-363 See GCSE Chemistry Chapter 5 pg. 70-79 6.1 Relative atomic mass. The relative atomic mass
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 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 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 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 informationGetting the most from this book...4 About this book...5
Contents Getting the most from this book...4 About this book....5 Content Guidance Topic 1 Atomic structure and the periodic table...8 Topic 2 Bonding and structure...14 Topic 2A Bonding....14 Topic 2B
More informationIB Chemistry. DP Chemistry Review
DP Chemistry Review Topic 1: Quantitative chemistry 1.1 The mole concept and Avogadro s constant Assessment statement Apply the mole concept to substances. Determine the number of particles and the amount
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 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 informationChemical 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 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 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 informationIB 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 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 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 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 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 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 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 informationSolution. Practice Exercise. Concept Exercise
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
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 informationChemistry 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 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 informationConcept 1. The meaning and usefulness of the mole. The mole (or mol) represents a certain number of objects.
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
More informationNuclear Structure. particle relative charge relative mass proton +1 1 atomic mass unit neutron 0 1 atomic mass unit electron -1 negligible mass
Protons, neutrons and electrons Nuclear Structure particle relative charge relative mass proton 1 1 atomic mass unit neutron 0 1 atomic mass unit electron -1 negligible mass Protons and neutrons make up
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 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 informationTOPIC 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 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 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 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 McGraw-Hill Companies,
More information@ Oxford Fajar Sdn. Bhd. (008974-T) 2012. Matter. 1.1 Atoms and Molecules 1.2 Mole Concept 1.3 Stoichiometry
1 Matter 1.1 Atoms and Molecules 1.2 Mole Concept 1.3 Stoichiometry 2 Chemistry for Matriculation Semester 1 1.1 Atoms and Molecules LEARNING OUTCOMES Describe proton, electron and neutron in terms of
More information7.4. Using the Bohr Theory KNOW? Using the Bohr Theory to Describe Atoms and Ions
7.4 Using the Bohr Theory LEARNING TIP Models such as Figures 1 to 4, on pages 218 and 219, help you visualize scientific explanations. As you examine Figures 1 to 4, look back and forth between the diagrams
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 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 informationThe 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 informationAtomic Structure. Name Mass Charge Location Protons 1 +1 Nucleus Neutrons 1 0 Nucleus Electrons 1/1837-1 Orbit nucleus in outer shells
Atomic Structure called nucleons Name Mass Charge Location Protons 1 +1 Nucleus Neutrons 1 0 Nucleus Electrons 1/1837-1 Orbit nucleus in outer shells The number of protons equals the atomic number This
More informationINTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION. 37 74 20 40 60 80 m/e
CHM111(M)/Page 1 of 5 INTI COLLEGE MALAYSIA A? LEVEL PROGRAMME CHM 111: CHEMISTRY MOCK EXAMINATION: DECEMBER 2000 SESSION SECTION A Answer ALL EIGHT questions. (52 marks) 1. The following is the mass spectrum
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 informationSTOICHIOMETRY UNIT 1 LEARNING OUTCOMES. At the end of this unit students will be expected to:
STOICHIOMETRY LEARNING OUTCOMES At the end of this unit students will be expected to: UNIT 1 THE MOLE AND MOLAR MASS define molar mass and perform mole-mass inter-conversions for pure substances explain
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 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 informationChapter 3 Stoichiometry
Chapter 3 Stoichiometry 3-1 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 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 informationChemistry Diagnostic Questions
Chemistry Diagnostic Questions Answer these 40 multiple choice questions and then check your answers, located at the end of this document. If you correctly answered less than 25 questions, you need to
More informationCandidate Style Answer
Candidate Style Answer Chemistry A Unit F321 Atoms, Bonds and Groups High banded response This Support Material booklet is designed to accompany the OCR GCE Chemistry A Specimen Paper F321 for teaching
More informationF321 THE STRUCTURE OF ATOMS. ATOMS Atoms consist of a number of fundamental particles, the most important are... in the nucleus of an atom
Atomic Structure F32 TE STRUCTURE OF ATOMS ATOMS Atoms consist of a number of fundamental particles, the most important are... Mass / kg Charge / C Relative mass Relative Charge PROTON NEUTRON ELECTRON
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 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 informationUnit 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 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 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 10-24 g How many 12 C atoms weigh 12 g?
More informationWoods Chem-1 Lec-02 10-1 Atoms, Ions, Mole (std) Page 1 ATOMIC THEORY, MOLECULES, & IONS
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
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 informationChapter 2: The Chemical Context of Life
Chapter 2: The Chemical Context of Life Name Period This chapter covers the basics that you may have learned in your chemistry class. Whether your teacher goes over this chapter, or assigns it for you
More informationneutrons are present?
AP Chem Summer Assignment Worksheet #1 Atomic Structure 1. a) For the ion 39 K +, state how many electrons, how many protons, and how many 19 neutrons are present? b) Which of these particles has the smallest
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 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 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 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 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 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 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 informationCHAPTER 8: CHEMICAL COMPOSITION
CHAPTER 8: CHEMICAL COMPOSITION Active Learning: 1-4, 6-8, 12, 18-25; End-of-Chapter Problems: 3-4, 9-82, 84-85, 87-92, 94-104, 107-109, 111, 113, 119, 125-126 8.2 ATOMIC MASSES: COUNTING ATOMS BY WEIGHING
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 informationChemistry Assessment Unit AS 1
Centre Number 71 Candidate Number ADVANCED SUBSIDIARY (AS) General Certificate of Education January 2011 Chemistry Assessment Unit AS 1 assessing Basic Concepts in Physical and Inorganic Chemistry [AC111]
More informationTopic 4 National Chemistry Summary Notes. Formulae, Equations, Balancing Equations and The Mole
Topic 4 National Chemistry Summary Notes Formulae, Equations, Balancing Equations and The Mole LI 1 The chemical formula of a covalent molecular compound tells us the number of atoms of each element present
More informationStoichiometry. 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 informationStoichiometry Review
Stoichiometry Review There are 20 problems in this review set. Answers, including problem set-up, can be found in the second half of this document. 1. N 2 (g) + 3H 2 (g) --------> 2NH 3 (g) a. nitrogen
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 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 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 informationChemical 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 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 informationHonors 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 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 informationCoimisiún na Scrúduithe Stáit State Examinations Commission
2015. M33 Coimisiún na Scrúduithe Stáit State Examinations Commission LEAVING CERTIFICATE EXAMINATION, 2015 CHEMISTRY ORDINARY LEVEL TUESDAY, 16 JUNE AFTERNOON 2.00 TO 5.00 400 MARKS Answer eight questions
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 informationChem 1100 Chapter Three Study Guide Answers Outline I. Molar Mass and Moles A. Calculations of Molar Masses
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
More informationChapter 1 The Atomic Nature of Matter
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.
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 informationHow To Calculate Mass In Chemical Reactions
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 informationEXPERIMENT 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 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 informationLecture 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 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 informationTest Bank - Chapter 4 Multiple Choice
Test Bank - Chapter 4 The questions in the test bank cover the concepts from the lessons in Chapter 4. Select questions from any of the categories that match the content you covered with students. The
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 informationStoichiometry of Formulas and Equations
sil07204_ch03_69-107 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 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 informationStoichiometry. Unit Outline
3 Stoichiometry Unit Outline 3.1 The Mole and Molar Mass 3.2 Stoichiometry and Compound Formulas 3.3 Stoichiometry and Chemical Reactions 3.4 Stoichiometry and Limiting Reactants 3.5 Chemical Analysis
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 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 informationChapter 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 informationF321 MOLES. Example If 1 atom has a mass of 1.241 x 10-23 g 1 mole of atoms will have a mass of 1.241 x 10-23 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 informationIonic and Metallic Bonding
Ionic and Metallic Bonding BNDING AND INTERACTINS 71 Ions For students using the Foundation edition, assign problems 1, 3 5, 7 12, 14, 15, 18 20 Essential Understanding Ions form when atoms gain or lose
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 informationAtoms, Elements, and the Periodic Table (Chapter 2)
Atoms, Elements, and the Periodic Table (Chapter 2) Atomic Structure 1. Historical View - Dalton's Atomic Theory Based on empirical observations, formulated as Laws of: Conservation of Mass Definite Proportions
More informationThe 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 informationChem 31 Fall 2002. Chapter 3. Stoichiometry: Calculations with Chemical Formulas and Equations. Writing and Balancing Chemical Equations
Chem 31 Fall 2002 Chapter 3 Stoichiometry: Calculations with Chemical Formulas and Equations Writing and Balancing Chemical Equations 1. Write Equation in Words -you cannot write an equation unless you
More informationPart B 2. Allow a total of 15 credits for this part. The student must answer all questions in this part.
Part B 2 Allow a total of 15 credits for this part. The student must answer all questions in this part. 51 [1] Allow 1 credit for 3 Mg(s) N 2 (g) Mg 3 N 2 (s). Allow credit even if the coefficient 1 is
More information