1. *Pick up computer, log-in and go to podcast page.
THURSDAY, SEPTEMBER 13, 2012
*Pick up computer, log-in and go to podcast page.
*Have out the quiz sheet from yesterday.
*SEE ME immediately with the 3.1/3.2 worksheet if you had not turned in previously.
CW: Check homework problems and quiz sheet
CW: Computer Review Games & Chemthink.com
CW/HW: Study Guide Questions and TEST due tomorrow!
Chapter 3 Review sheet handout & Avogadro’s Number Mini-Lab may do as well...
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2. Chapter 3 Lesson Starter
Section 3 Counting Atoms
Chapter 3
Lesson Starter
Imagine that your semester grade depends 60% on exam scores and 40% on laboratory explorations.
Your exam scores would count more heavily toward your final grade.
In this section, you will learn that the atomic mass of an element is a weighted average of the masses of the naturally occurring isotopes of that element.
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3. Opener #2 - Tuesday, January 29, 2013
1. What does the Law of Conservation of Mass state?
2. How does NaCl (table salt) follow the Law of Definite Proportions?
3. How does the diagram depict the Law of Multiple Proportions?
CW: Notes 3.3 together...
CW: M&Mium isotope lab
CW: Chemthink.com if time
permits
HW: Study Guide due FRI
BUT TEST is on FRIDAY
for ch. 3 only.
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4. Opener #3 - Tuesday, Sept. 11, 2012
1. What does the Law of Conservation of Mass state?
The mass of the reactants is the same as the total mass of the products. Matter cannot be created or destroyed.
2. How does NaCl (table salt) follow the Law of Definite Proportions? It is always made up of same ratio of element which is 39.34% Na and 60.66% Cl.
3. How does the diagram depict the Law of Multiple Proportions?
If amount of H remains the same
but if twice atoms of Oxygen &
H still has same amount, then
oxygen mass must also double.
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5. Chapter 3 Objectives Explain what isotopes are.
Section 3 Counting Atoms
Chapter 3
Objectives
Explain what isotopes are.
Define atomic number and mass number, and describe how they apply to isotopes.
Given the identity of a nuclide, determine its number of protons, neutrons, and electrons.
Define mole, Avogadro’s number, and molar mass, and state how all three are related.
Solve problems involving mass in grams, amount in moles, and number of atoms of an element.
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6. Distinguishing Among Atoms
3.3
Connecting to Your World
Just as apples come in different varieties, a chemical element can come in different “varieties” called isotopes.
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7. Atomic Number What makes one element different from another? 3.3 >
Distinguishing Among Atoms
>
Atomic Number
Atomic Number
What makes one element different from another?
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8. Section 3 Counting Atoms
Chapter 3
Atomic Number
Atoms of different elements have different numbers of protons.
Atoms of the same element all have the same number of protons.
The atomic number (Z) of an element is the number of protons of each atom of that element.
The atomic number identifies the element.
Because all atoms are neutral, the number of protons equals the number of electrons.
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9. 3.3
Distinguishing Among Atoms
>
Atomic Number
Elements are different because they contain different numbers of protons.
The atomic number of an element is the number of protons in the nucleus of an atom of that element.
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10. 3.3 > Distinguishing Among Atoms Atomic Number 10 End Show Slide
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11. Slide
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12. Atomic Number
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13. Slide
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14. for Conceptual Problem 4.15
Practice Problems
Click here for Problem 4.15
to check answers
Problem Solving 4.15 Solve Problem 15 with the help of an interactive guided tutorial.
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15. Chapter 3 Atomic Number ⬅atomic number Visual Concepts Chapter menu
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16. Mass Number How do you find the number of neutrons in an atom? 3.3
Distinguishing Among Atoms
>
Mass Number
Mass Number
How do you find the number of neutrons in an atom?
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17. 3.3
Distinguishing Among Atoms
>
Mass Number
The total number of protons and neutrons in an atom is called the mass number.
The number of neutrons in an atom is the difference between the mass number and atomic number.
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of 52 17
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18. Average Mass Number, atomic weight or atomic mass
Visual Concepts
Chapter 3
Average Mass Number, atomic weight or atomic mass
⬅average mass number
or average atomic weight
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19. 4.1 SAMPLE PROBLEM End Show Slide of 52
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20. 4.1 SAMPLE PROBLEM End Show Slide of 52
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21. 4.1 SAMPLE PROBLEM End Show Slide of 52
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22. 4.1 SAMPLE PROBLEM End Show Slide of 52
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23. for Sample Problem 4.1
Practice Problems
Click here to check answers.
Problem Solving 4.17 Solve Problem 17 with the help of an interactive guided tutorial.
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24. Chapter 3 Isotopes and Nuclides Visual Concepts Chapter menu Resources
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25. Section 3 Counting Atoms
Chapter 3
Isotopes
Isotopes are atoms of the same element that have different masses.
The isotopes of a particular element all have the same number of protons and electrons but different numbers of neutrons.
Most of the elements consist of mixtures of isotopes.
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26. 3.3
Distinguishing Among Atoms
>
Isotopes
Despite these differences, isotopes are chemically alike because they have identical numbers of protons and electrons.
Neon-20, neon-21, and neon-22 are three isotopes of neon, a gaseous element used in lighted signs. Comparing and Contrasting How are these isotopes different? How are they similar?
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27. Section 3 Counting Atoms
Chapter 3
Mass Number
The mass number is the total number of protons and neutrons that make up the nucleus of an isotope.
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28. Chapter 3 Designating Isotopes
Section 3 Counting Atoms
Chapter 3
Designating Isotopes
Hyphen notation: The mass number is written with a hyphen after the name of the element.
uranium-235
U-235
Nuclear symbol: The superscript indicates the mass number and the subscript indicates the atomic number.
mass number--➡
atomic number➡
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29. Designating Isotopes, continued
Section 3 Counting Atoms
Chapter 3
Designating Isotopes, continued
The number of neutrons is found by subtracting the atomic number from the mass number.
mass number − atomic number = number of neutrons
235 (protons + neutrons) − 92 protons = 143 neutrons
Nuclide is a general term for a specific isotope of an element.
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30. Chapter 3 Hydrogen Isotopes
Section 3 Counting Atoms
Chapter 3
Hydrogen Isotopes
There are 3 special names for hydrogen isotopes.
All Hydrogen atoms have 1 proton and 1 electron but vary in the number of neutrons as all isotopes do.
Protium, H-1, is the most common type, %, nucleus consists of 1 proton and no neutrons.
Deuterium, H-2, accounts for % of Earth’s hydrogen and has 1 proton and 1 neutron.
Tritium, H-3, accounts for % of Earth’s hydrogen, nucleus consists of 1 proton and 2 neutrons.
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31. Designating Isotopes, continued
Section 3 Counting Atoms
Chapter 3
Designating Isotopes, continued
Sample Problem A
How many protons, electrons, and neutrons are there in an atom of chlorine-37?
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32. Designating Isotopes, continued
Section 3 Counting Atoms
Chapter 3
Designating Isotopes, continued
Sample Problem A Solution
Given: name and mass number of chlorine-37
Unknown: numbers of protons, electrons, and neutrons
Solution:
atomic number = number of protons = number of electrons
mass number = number of neutrons + number of protons
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33. Designating Isotopes, continued
Section 3 Counting Atoms
Chapter 3
Designating Isotopes, continued
Sample Problem A Solution, continued
mass number of chlorine-37 − atomic number of chlorine = number of neutrons in chlorine-37
mass number − atomic number = 37 (protons plus neutrons) − 17 protons = 20 neutrons
An atom of chlorine-37 is made up of 17 electrons, 17 protons, and 20 neutrons.
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34. for Conceptual Problem 4.20
Practice Problems
Click here to check answers 4.20
Problem Solving 4.20
Solve Problem 20 with the help of an interactive guided tutorial.
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of 52
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35. Relative Atomic Masses
Section 3 Counting Atoms
Chapter 3
Relative Atomic Masses
The standard used by scientists to compare units of atomic mass is the carbon-12 atom, which has been arbitrarily assigned a mass of exactly 12 atomic mass units, or 12 amu.
One atomic mass unit, or 1 amu, is exactly 1/12 the mass of a carbon-12 atom.
The atomic mass of any atom is determined by comparing it with the mass of the carbon-12 atom.
Isotopes have different masses, but have similar chemical behavior. Protons & neutrons masses are close to 1 amu.
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36. COMPOSITION OF THE ATOM CONCEPT MAP ACTIVITY
CLICK HERE FOR CONCEPT MAP ACTIVITY ON ATOM
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37. M&M Isotope Mini-Lab Stop here and do this activity lab. Chapter menu
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38. Atomic Mass How do you calculate the atomic mass of an element? 3.3
Distinguishing Among Atoms
>
Atomic Mass
Atomic Mass
How do you calculate the atomic mass of an element?
Slide
of 52 38
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39. Average Atomic Masses of Elements
Section 3 Counting Atoms
Chapter 3
Average Atomic Masses of Elements
Average atomic mass is the weighted average of the atomic masses of the naturally occurring isotopes of an element.
Calculating Average Atomic Mass
The average atomic mass of an element depends on both the mass and the relative abundance of each of the element’s isotopes.
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40. Chapter 3 Average Atomic Mass
Visual Concepts
Chapter 3
Average Atomic Mass
Click below to watch the Visual Concept.
Visual Concept
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41. Average Atomic Masses of Elements, continued
Section 3 Counting Atoms
Chapter 3
Average Atomic Masses of Elements, continued
Copper consists of 69.15% copper-63, which has an atomic mass of amu, and 30.85% copper- 65, which has an atomic mass of amu.
Calculating Average Atomic Mass, continued
The average atomic mass of copper can be calculated by multiplying the atomic mass of each isotope by its relative abundance (expressed in decimal form) and adding the results.
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42. Average Atomic Masses of Elements, continued
Section 3 Counting Atoms
Chapter 3
Average Atomic Masses of Elements, continued
Calculating Average Atomic Mass, continued
( × amu) + ( × amu) = amu
The calculated average atomic mass of naturally occurring copper is amu.
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43. Slide
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44. Slide
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45. Slide
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46. For example, carbon has two stable isotopes:
3.3
Distinguishing Among Atoms
>
Atomic Mass
For example, carbon has two stable isotopes:
Carbon-12, which has a natural abundance of %, and
Carbon-13, which has a natural abundance of 1.11%.
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47. START HERE WEDNESDAY End Show Slide of 52
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48. Opener #4 - Wednesday, Sept. 12, 2012
1. Calculate the weighted average atomic mass if
CW: Notes 3.3B + problems together...
CW: How many room of M&M’s is Avogadro’s # mini-lab?
CW: QUIZ & Chemthink.com
Last chance to get points for ch w/sheet IN BOX.
HW: Study Guide due FRI AND TEST is on FRIDAY
for ch. 3 only.
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49. 4.2 SAMPLE PROBLEM OPENER ANSWER WORKED OUT... End Show Slide of 52
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50. 4.2 SAMPLE PROBLEM End Show Slide of 52
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51. 3.3
Distinguishing Among Atoms
>
Atomic Mass
To calculate the weighted average atomic mass of an element, multiply the mass of each isotope by its natural abundance, expressed as a decimal, and then add the products.
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of 52 51
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52. 4.2 SAMPLE PROBLEM End Show Slide of 52
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53. 4.2 SAMPLE PROBLEM End Show Slide of 52
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54. for Conceptual Problem 4.3
Practice Problems
for Conceptual Problem 4.3
for Conceptual Problem 4.3
Problem Solving 4.21 Solve Problem 21 with the help of an interactive guided tutorial.
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55. for Conceptual Problem 4.3
Practice Problems
for Conceptual Problem 4.3
for Conceptual Problem 4.3
ANSWER: Since is closer to 11 than to 10, B-11 would occur in nature at a higher percentage than that of B-10. If these were the only 2 isotopes of Boron, you could determine the exact percentages.
Problem Solving 4.21 Solve Problem 21 with the help of an interactive guided tutorial.
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56. for Sample Problem 4.2
Practice Problems
Click here to check answer
Problem Solving 4.24 Solve Problem 24 with the help of an interactive guided tutorial.
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of 52
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57. The Mole: A Measurement of Matter
10.1
The Mole: A Measurement of Matter
You could measure the amount of sand in a sand sculpture by counting each grain of sand, but it would be much easier to weigh the sand. You’ll discover how chemists measure the amount of a substance using a unit called a mole, which relates the number of particles to the mass.
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58. 10.1
The Mole: A Measurement of Matter
>
Measuring Matter
Measuring Matter
What are three methods for measuring the amount of something?
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of 43 58
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59. 10.1
The Mole: A Measurement of Matter
>
Measuring Matter
You often measure the amount of something by one of three different methods—by count, by mass, and by volume.
You can buy items by different types of measurements, such as a count, a weight or mass, or a volume. Classifying Which of these common items are being sold by weight? By volume? By count?
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of 43 59
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60. Visual Concepts
Chapter 3
The Mole
Click below to watch the Visual Concept.
Visual Concept
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61. Relating Mass to Numbers of Atoms
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms
The Mole
The mole is the SI unit for amount of substance.
A mole (abbreviated mol) is the amount of a substance that contains as many particles as there are atoms in exactly 12 g of carbon-12.
Avogadro’s Number
Avogadro’s number— × 1023—is the number of particles in exactly one mole of a pure substance.
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62. Avogadro’s Number - Don’t show yet until after mini-lab
Visual Concepts
Chapter 3
Avogadro’s Number - Don’t show yet until after mini-lab
Click below to watch the Visual Concept.
Visual Concept
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63. 10.1
The Mole: A Measurement of Matter
>
What is a Mole?
A mole of any substance contains Avogadro’s number or 6.02 × representative particles.
The term representative particle refers to the species present in a substance: usually atoms, molecules, or formula units.
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64. Converting Number of Particles to Moles
10.1
The Mole: A Measurement of Matter
>
What is a Mole?
Converting Number of Particles to Moles
One mole (mol) of a substance is 6.02 × representative particles of that substance and is the SI unit for measuring the amount of a substance.
The number of representative particles in a mole, 6.02 × 1023, is called Avogadro’s number.
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65. 10.1
The Mole: A Measurement of Matter
>
What is a Mole?
*1 mole of any element or compound is always ___________ to a mole of another compound in the amount of substance but will have different masses.
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66. The Mass of a Mole of an Element
10.1
The Mole: A Measurement of Matter
>
The Mass of a Mole of an Element
The Mass of a Mole of an Element
How is the atomic mass of an element related to the molar mass of an element?
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of 43 66
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67. The Mass of a Mole of an Element
10.1
The Mole: A Measurement of Matter
>
The Mass of a Mole of an Element
The atomic mass of an element expressed in grams is the mass of a mole of the element.
The mass of a mole of an element is its molar mass.
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of 43 67
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68. The Mass of a Mole of an Element
10.1
The Mole: A Measurement of Matter
>
The Mass of a Mole of an Element
One molar mass of carbon, sulfur, mercury, and iron are shown.
One molar mass of carbon, sulfur, mercury, and iron are shown. Each of the quantities contains one mole of the element. Applying Concepts How many atoms of each element are shown?
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69. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Molar Mass
The mass of one mole of a pure substance is called the molar mass of that substance.
Molar mass is usually written in units of g/mol.
The molar mass of an element is numerically equal to the atomic mass of the element in atomic mass units.
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70. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Gram/Mole Conversions
Chemists use molar mass as a conversion factor in chemical calculations.
For example, the molar mass of helium is 4.00 g He/mol He.
To find how many grams of helium there are in two moles of helium, multiply by the molar mass.
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71. The Mass of a Mole of a Compound
10.1
The Mole: A Measurement of Matter
>
The Mass of a Mole of a Compound
The Mass of a Mole of a Compound
How is the mass of a mole of a compound calculated?
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72. The Mass of a Mole of a Compound
10.1
The Mole: A Measurement of Matter
>
The Mass of a Mole of a Compound
To calculate the molar mass of a compound, find the number of grams of each element in one mole of the compound. Then add the masses of the elements in the compound.
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73. The Mass of a Mole of a Compound
10.1
The Mole: A Measurement of Matter
>
The Mass of a Mole of a Compound
Substitute the unit grams for atomic mass units. Thus 1 mol of SO3 has a mass of 80.1 g.
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74. 10.4 SAMPLE PROBLEM End Show Slide of 43
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75. 10.4 SAMPLE PROBLEM End Show Slide of 43
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76. 10.4 SAMPLE PROBLEM End Show Slide of 43
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77. 10.4 SAMPLE PROBLEM End Show Slide of 43
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78. for Sample Problem 10.4
Practice Problems
Problem Solving 10.7 Solve Problem 7 with the help of an interactive guided tutorial.
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79. GRAM-MOLE CONVERSIONS PROBLEM ACTIVITY - see online book - skip for now.
CLICK HERE FOR GRAM/MOLE PROBLEM ACTIVITY
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80. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Conversions with Avogadro’s Number
Avogadro’s number can be used to find the number of atoms of an element from the amount in moles or to find the amount of an element in moles from the number of atoms.
In these calculations, Avogadro’s number is expressed in units of atoms per mole.
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81. AVOGADRO’S NUMBER CONVERSIONS PROBLEM ACTIVITY
CLICK HERE FOR AVOGADRO'S NUMBER PROBLEM ACTIVITY
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82. Chapter 3 Solving Mole Problems Section 3 Counting Atoms Chapter menu
Resources
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83. Determining the Mass from the Amount in Moles
Section 3 Counting Atoms
Chapter 3
Determining the Mass from the Amount in Moles
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84. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem B
What is the mass in grams of 3.50 mol of the element copper, Cu?
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85. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem B Solution
Given: 3.50 mol Cu
Unknown: mass of Cu in grams
Solution: the mass of an element in grams can be calculated by multiplying the amount of the element in moles by the element’s molar mass.
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86. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem B Solution, continued
The molar mass of copper from the periodic table is rounded to g/mol.
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87. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem C
A chemist produced 11.9 g of aluminum, Al. How many moles of aluminum were produced?
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88. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem C Solution
Given: 11.9 g Al
Unknown: amount of Al in moles
Solution:
The molar mass of aluminum from the periodic table is rounded to g/mol.
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89. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem D
How many moles of silver, Ag, are in 3.01 × atoms of silver?
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90. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem D Solution
Given: 3.01 × 1023 atoms of Ag
Unknown: amount of Ag in moles
Solution:
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91. Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem E
What is the mass in grams of 1.20 × 108 atoms of copper, Cu?
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92. Chapter 3 Relating Mass to Numbers of Atoms, continued
Section 3 Counting Atoms
Chapter 3
Relating Mass to Numbers of Atoms, continued
Sample Problem E Solution
Given: 1.20 × 108 atoms of Cu
Unknown: mass of Cu in grams
Solution:
The molar mass of copper from the periodic table is rounded to g/mol.
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93. Assess students’ understanding of the concepts in Section 10.1.
10.1 Section Quiz.
Assess students’ understanding of the concepts in Section
10.1.
Continue to: Launch:
-or-
Section Quiz
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94. 10.1 Section Quiz.
1. Three common ways of measuring the amount of something are by count, by mass, and
by temperature.
by volume.
by area.
by density.
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95. 2. A mole of hydrogen gas, H2(g), contains 6.02 x 1023 molecules.
10.1 Section Quiz.
2. A mole of hydrogen gas, H2(g), contains x 1023
molecules.
atoms.
amu.
grams.
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96. 3. The atomic mass of fluorine is 19.0 amu, so the molar mass is
10.1 Section Quiz.
3. The atomic mass of fluorine is 19.0 amu, so the molar mass is
19.0 amu.
19.0 g.
6.02 x 1023 amu.
6.02 x 1023 g.
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97. 4. Calculate the molar mass of ammonium nitrate. 45.02 g 80.05 g
10.1 Section Quiz.
4. Calculate the molar mass of ammonium nitrate.
45.02 g
80.05 g
60.06 g
48.05 g
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98. Assess students’ understanding of the concepts in Section 4.3.
3.3 Section Quiz
Assess students’ understanding of the concepts in Section
4.3.
Continue to: Launch:
-or-
Section Quiz
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99. 1. Isotopes of an element have the same mass number.
3.3 Section Quiz
1. Isotopes of an element have
the same mass number.
different atomic numbers.
the same number of protons but different numbers of neutrons.
the same number of protons but different numbers of electrons.
ANS: C PTS: 1 REF: p OBJ: 4.3.1
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100. 2. How many neutrons are in sulfur-33? 16 neutrons 33 neutrons
3.3 Section Quiz
2. How many neutrons are in sulfur-33?
16 neutrons
33 neutrons
17 neutrons
32.06 neutrons
ANS: C PTS: 1 REF: p OBJ: 4.3.2
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101. 3.3 Section Quiz
3. If sulfur contained 90.0% sulfur-32 and 10.0% sulfur-34, its atomic mass would be
32.2 amu.
32.4 amu.
33.0 amu.
35.4 amu.
ANS: A PTS: 1 REF: p OBJ: 4.3.3
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102. > Distinguishing Among Atoms Concept Map 102 End Show Slide of 52
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103. online SELF-CHECK QUIZ FOR SECT. 1.3
TAKE THE FOLLOWING QUIZ. Record your answers. Ask questions for any answer that you do not understand.
CLICK BELOW TO TAKE THE QUIZ. YOU MUST BE IN THE PLAY MODE OF THE SLIDE SHOW.
QUIZ SECTION 3.3 MODERN CHEMISTRY HOLT
RECORD THE 10 ANSWERS IN NOTES.
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104. VIDEOS FOR ADDITIONAL INSTRUCTION
Additional Videos for Section 3.3 Counting Atoms (5 videoclips)
Atomic Number - Isotopes (4:47)
Atomic Mass (4:19)
Chemistry Mole (5:16)
Molar Mass (5:32)
Avogadro's Principle (4:01)
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105. Chapter 3: Atoms: The Building Blocks of Matter Topic: Atomic Theory
SCI LINKS FOR CHAPTER
Additional Student SCI LINKS for CHAPTER 3
The NSTA-sponsored SciLinks Web site contains links to accurate and up-to-date science
information on the Internet. Just click on the button below to go to the SciLinks site at
and log in. Then, type in the SciLinks code for the topic you want to
research. The following is a list of the SciLinks codes for this chapter.
Chapter 3: Atoms: The Building Blocks of Matter
Topic: Atomic Theory
SciLinks code: HC60120
Topic: Carbon
SciLinks code: HC60214
Topic: Subatomic Particles
SciLinks code: HC61473
Topic: Isotopes
SciLinks code: HC60820
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106. End of Chapter 3 Show Chapter menu Resources
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