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The Mole Chapter11. I. Atoms, Molecules, and Formula units.

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Presentation on theme: "The Mole Chapter11. I. Atoms, Molecules, and Formula units."— Presentation transcript:

1 The Mole Chapter11

2 I. Atoms, Molecules, and Formula units

3 The terms atom, molecule, and formula units can be used to represent very similar things.

4 Atoms The term atoms is used to describe units of uncombined elements from the periodic table. Examples: O, U, Zr, and Ag are all atoms (no subscripts) O

5 Metals & Non-Metals

6 Molecules The term molecule is used to describe a molecular compound. This is any compound that contains only non-metals in its formula. Non-metals are found on the right side of the staircase on the periodic table, and also includes Hydrogen. Examples: S 8, N 2 O 2, O 3, and CO 2 are all molecules (all non-metals, more than one atom in the formula) OO C

7 Formula Units The term formula units are used to describe any unit of an ionic compound, which is any compound that contains a metal in its formula. Metals can be found on the left side of the staircase on a periodic table. Ex. CaO, NaI, and AgNO 3 are all formula units (metal in the formula, more than one atom in the formula) O Ca

8 The term formula units is long, so we’ll call it FUN. We could abbreviate with just the first letter of each word, but that can easily be misinterpreted as something else… yikes, we don’t want that do we?

9 Remember, a compound, molecular or ionic, is made up of at least 2 atoms from the periodic table.

10 Atom, Molecule or FUN? 1)H 2 O 2)Mg 3)NaNO 3 4)Cl 2 5)Ne 6)SC 7)KCl molecule atom Formula Unit molecule atom Molecule Formula Unit

11 I. The mole and Avogadro’s number

12 What is a mole? A machine that bores through hard surfaces, used especially for tunneling through rock. A spy who operates from within an organization, especially a double agent operating against his or her own government from within its intelligence establishment.

13 An animal

14

15 A birth mark

16 In Chemistry From the atomic structure unit we learned that 1 atom of any element is equal to the atomic mass on the periodic table. The units for atomic mass is amu (atomic mass unit)

17 Example: 1 atom of hydrogen = 1.008 amu of hydrogen

18 However, in a laboratory it would be difficult to work with atoms, since they are so small Instead we use the same atomic masses on the periodic table, but use the units of grams (per mole)

19 Example: 1 mole of hydrogen = 1.008 grams of hydrogen

20 The value of the mole was experimentally defined by the number of carbon atoms in 12.01 grams of carbon. There are 6.02 x 10 23 atoms of carbon in 12.01 grams of carbon. 6.02 x 10 23 is referred to as Avogadro’s number. It represents a specific amount of something.

21 It’s really just a word to represent a number…

22 Just like: a couple of cookies = __2__ cookies a dozen doughnuts = _12_ doughnuts a gross of geese = __144___ geese;

23 a mole of mints = 6.02 x 10 23 mints a mole of basketballs = 6.02 x 10 23 basketballs a mole of marshmallows = 6.02 x 10 23 marshmallows

24 "mole" represents the number 6.0221367 x 10 23 or 602000000000000000000000

25 A mole of anything can be difficult to imagine. A mole of marbles is enough to cover the earth to a depth of 50 miles! Whoa, that’s a lot of marbles.

26 Although a mole can be used to describe any type of object, it is usually limited to subatomic particles. a mole of atoms = 6.02 x 10 23 atoms a mole of molecules = 6.02 x 10 23 molecules a mole of formula units = 6.02 x 10 23 formula units

27 Atom, Molecule, & FUN Molecule = Compound with only Non-Metals (mc or molec) Formula Unit (FUN) = Compound with a Metal Atom = single PT element *don’t abbreviate molecule as mol or mole

28 In your box… 1 mole = 6.02 X 10 23 atoms, molecules, or formula units

29 Three ways of representing amounts 12 large eggs 1 dozen eggs 24 ounces of eggs 6.02 X 10 23 Iron atoms 1 mole of iron atoms 55.847 grams of iron

30 Fun Facts It is often referred to as Avogadro's number (in honor of Amedeo Avogadro) “Mole” is derived from the Latin word moles, which means “a mass” “Molecule” is the diminutive form of this word that means “a small mass”

31 Mole day is generally celebrated on October 23 10 23 AT 6:02AM get it?

32 To compare…. A dozen of eggs will fit in an egg carton A mole of eggs will fill all the oceans on the earth more than 30 million times over It would take 10 billion chickens laying 10 eggs per day more than 10 billion years to lay a mole of eggs

33 Why use such a big number? We use moles when it comes to atoms and molecules… take a guess? Because atoms are so small

34 B. Calculating with Avogadro’s Number Remember, Avogadro’s number is an equality and you can make 2 conversion factors out of it. Use dimensional analysis to determine the information you are seeking.

35 The two conversion factors 1 mol___ 6.02 x 10 23 * 1 mole and * = atoms, molecules, or formula un its

36 EX 1: Determine the moles of magnesium there are in 1.23 x 10 24 atoms of magnesium 1.23 x 10 24 atoms Mg 1 mole Mg 6.02 x 10 23 atoms Mg = 2.04mol Mg 1 G: W: R: 1.23 x 10 24 atoms Mg Moles Mg 1 mole Mg = 6.02 x 10 23 atoms Mg

37 When you see atoms, molecules, or FUN in a problem your relationship is: 1 mol __ = 6.02 x 10 23 atom, mc, or fun __

38 EX 2: Determine the number of atoms in 8.93 moles of argon. 8.93 moles Ar 1 mole Ar 6.02 x 10 23 atoms Ar = 5.38 x 10 24 Atom Ar 1 G: W: R: 8.93 moles Ar atoms Ar 1 mole Ar = 6.02 x 10 23 atoms Ar

39 Ex 3: Determine the number of water molecules in 11.2 moles of water. 11.2 moles H 2 O 6.02 x 10 23 molecules H 2 O = 6.74 x 10 24 1 moles H 2 O molecules H 2 O 1 G: W: R: 11.2 moles H 2 O Molecules H 2 O 1 mole H 2 O = 6.02 x 10 23 mc H 2 O

40 More Practice

41 1. Determine the number of atoms in 0.056 mol of plutonium 0.056 mol Pu 1 mole Pu 6.02 x 10 23 atoms Pu = 3.37 x 10 22 Atoms Pu 1 G: 0.056 mol Pu W: atoms Pu R: 1 mole Pu = 6.02 x 10 23 atoms Pu

42 2. How many moles are in 1.20 x 10 25 atoms of phosphorus? 1.20 x 10 25 atoms P 1 mole P 6.02 x 10 23 atoms P =19.9Moles of Phosphorus 1 G: 1.20 x 10 25 atoms P W: moles P R: 1 mole P = 6.02 x 10 23 atoms P

43 3. How many moles are in 5.24 x 10 25 molecules of CCl 4 ? 5.24 x 10 25 molec. CCl 4 1 mole CCl 4 6.02 x 10 23 molec. CCl 4 =87.0Moles CCl 4 1 G: 5.24 x 10 25 atoms CCl 4 W: mc CCl 4 R: 1 mole CCl 4 = 6.02 x 10 23 mc CCl 4

44 Practice Answers 1. 2. 3. =3.37 x 10 22 Atoms Pu =19.9Moles of Phosphorus =87.0Moles CCl 4

45 C. Molar Mass

46 1. Definition molar mass is the mass (in grams) of 1 mole of any element or compound units for molar mass: g/mol Example: Hydrogen’s molar mass is 1.008 g/mol

47 the molar mass of any element equals the average atomic mass on the periodic table in grams

48 Use your periodic table 1 mol He = 4.0026 grams He 1 mol Ca = 40.08 grams Ca Other representation for Helium 1 mol He= 4.0026 grams He 4.0026 grams1 mol He

49 (use a periodic table) the molar mass of iron is 55.85 g/mol 55.85 g = 1 mole clean fraction 55.85g Fe 1 mol Fe

50 the molar mass of gold is 196.967g/mol 196.967g Au = 1 mol Au clean fraction 196.967g Au 1 mol Au

51 anytime you want to convert from mass (grams) to moles or moles to mass (grams), use molar mass! Tip: if you see mass (or grams) use your periodic table

52 B. Calculating with Molar Mass

53 B. Calculating with molar mass EX 1: Determine the mass of 3.50 mol of copper. 3.50 mol Cu63.546g Cu 1 mol Cu = 222 g Cu 1 G: W: R: 3.50 moles Cu Mass Cu (g) 1 mole Cu = 63.546 g Cu

54 When you see atoms, molecules, or FUN in a problem your relationship is: 1 mol __ = 6.02 x 10 23 atom, mc, or fun __ When you see mass in a problem your relationship is: 1 mol __ = (molar mass) g ___

55 Ex. 2 Determine the number of moles in 11.9 kg of aluminum. 11.9 kg Al1000g Al 1 kg Al = 441 1 mol Al 26.982g Al mol Al 1 G: 11.9 kg Al W: mol Al R: 1 mole Al = 26.982 g Al 1 kg = 1000 g G: W: R: 11.9 kg Al Moles Al 1 mole Al = 26.982 g Al 1 kg = 1000 g

56 More Practice

57 1. Determine the number of moles in 150 g of sulfur 150g S1 mol S 32.066g S = 4.68 mol S 1 G: 150 g S W: mol S R: 1 mole S = 32.066 g S

58 2. Determine the mass of 8.95 mol of Li 8.95 mol Li6.941 g Li 1 mol Li = 62.1g Li 1 G: 8.95 mol Li W: mass (g) R: 1 mole Li = 6.941 g Li

59 3. Determine the mass, in kg, of 12.4 mol of Na. 12.4 mol Na22.990g Na 1 mol Na = 0.285 1 kg 1000g kg Na 1 G: 12.4 mol Na W: mass (kg) R: 1 mole Na = 22.990 g Na 1 kg = 1000 g

60 C. Mixed Problems

61 Tips for solving mole problems 1.If you see “atoms,” “molecules,” or “formula units” mentioned in the problem, write 1 mole X = 6.02 X 10 23 atoms, molecules, formula units X. X = element or compound

62 Tips for solving mole problems 2. If you see mass involved in the problem, write 1 mol X = (see periodic table) g X X = element

63 Ex 1. Determine the mass of 4.56 x 10 24 atoms of silver. 4.56 x 10 24 atoms Ag107.868g Ag1 mol Ag = 817 1 mol Ag 6.02 x 10 23 atoms Ag g Ag 1 G: 4.56 x 10 24 atoms Ag W: mass (g) R: 1 mole Ag = 107.868 g Ag 1 mol Ag = 6.02 x 10 23 atoms Ag

64 Ex. 2 Determine the number of atoms in 100 g of aluminum 1 mol Al26.982g Al 100 g Al = 2.23 x 10 24 1 mol Al6.02 x 10 23 atoms Al Atoms Al 1 G: 100 g Al W: atoms R: 1 mole Al = 26.982 g Al 1 mol Al = 6.02 x 10 23 atoms Al

65 More Practice 1. Determine the number of atoms in 0.46 g of copper. 2. Determine the mass (in kg) of 5.98 x 10 26 atoms of potassium. 3. Which has more atoms, 26.982 g of aluminum or 4.003 g of helium?

66 1. Determine the number of atoms in 0.46 g of copper. 1 mol Cu63.546 g Cu 0.46g Cu = 4.36 x 10 21 1 mol Cu6.02 x 10 23 atoms Cu Atoms Cu 1 G: W: R: 0.46 g Cu Atoms Cu 1 mole Cu = 6.02 x 10 23 atoms Cu

67 2. Determine the mass (in kg) of 5.98 x 10 26 atoms of K. 5.98 x 10 26 atoms K39.098g K1 mol K = 38.8 1 mol K 6.02 x 10 23 atoms K kg K 1 1000g K 1 kg K G: W: R: 5.98 x 10 26 atoms K kg K 1 mole K = 6.02 x 10 23 atoms K 1 kg K = 1000 g K

68 3. Which has more atoms, 26.982 g of aluminum or 4.003 g of helium? 1 mol Al26.982 g Al = 6.02 x 10 23 1 mol Al6.02 x 10 23 atoms Al Atoms Al 1 1 mol He4.003 g He = 6.02 x 10 23 1 mol He6.02 x 10 23 atoms He Atoms He 1

69 …I don’t get atoms

70 A closer look If 4 grams of helium is equal to one mole of helium atoms and 12 grams of carbon is equal to one mole of carbon atoms How can we explain 1 mole = 6.02 X x 10 23 atoms?

71 1 mole He 1 mole C 4.006 g/mol12.001 g/mol 6.02 X 10 23 atoms He 6.02 X 10 23 atoms C

72 Conclusion Helium atoms are smaller than carbon atoms

73 Don’t forget what you learned before What does a mass number of 4 represent? Answer: protons + neutrons

74 Mole and Weight Relationships of Water and its Parts 2 moles +1 mole=1 mole H O H 2 O 2 * 1.01 g+ 16.00 g = 18.02 g

75 2 moles + 1 mole = 1 mole HO H 2 O 2 * 1.01 g+ 16.00 g = 18.02 g


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