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1 Chemical Quantities The Mole. 2 Collection Terms A collection term states a specific number of items. 1 dozen donuts = 12 donuts 1 ream of paper = 500.

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Presentation on theme: "1 Chemical Quantities The Mole. 2 Collection Terms A collection term states a specific number of items. 1 dozen donuts = 12 donuts 1 ream of paper = 500."— Presentation transcript:

1 1 Chemical Quantities The Mole

2 2 Collection Terms A collection term states a specific number of items. 1 dozen donuts = 12 donuts 1 ream of paper = 500 sheets 1 case = 24 cans Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

3 3 A mole is a collection that contains the same number of particles as there are carbon atoms in 12.0 g of carbon. 6.02 x 10 23 atoms of an element (Avogadros number). 1 mole element Number of Atoms 1 mole C = 6.02 x 10 23 C atoms 1 mole Na = 6.02 x 10 23 Na atoms 1 mole Au= 6.02 x 10 23 Au atoms A Mole of Atoms

4 4 A mole of a covalent compound has Avogadros number of molecules. 1 mole CO 2 = 6.02 x 10 23 CO 2 molecules 1 mole H 2 O = 6.02 x 10 23 H 2 O molecules of an ionic compound contains Avogadros number of formula units. 1 mole NaCl = 6.02 x 10 23 NaCl formula units 1 mole K 2 SO 4 = 6.02 x 10 23 K 2 SO 4 formula units A Mole of a Compound

5 5 Samples of One Mole Quantities 1 mole C=6.02 x 10 23 C atoms 1 mole Al=6.02 x 10 23 Al atoms 1 mole S=6.02 x 10 23 S atoms 1 mole H 2 O=6.02 x 10 23 H 2 O molecules 1 mole CCl 4 =6.02 x 10 23 CCl 4 molecules

6 6 Avogadros number 6.02 x 10 23 can be written as an equality and two conversion factors. Equality: 1 mole = 6.02 x 10 23 particles Conversion Factors: 6.02 x 10 23 particles and 1 mole 1 mole6.02 x 10 23 particles Avogadros Number

7 7 Using Avogadros Number Avogadros number is used to convert moles of a substance to particles. How many Cu atoms are in 0.50 mole Cu? 0.50 mole Cu x 6.02 x 10 23 Cu atoms 1 mole Cu = 3.0 x 10 23 Cu atoms Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

8 8 Using Avogadros Number Avogadros number is used to convert particles of a substance to moles. How many moles of CO 2 are in 2.50 x 10 24 molecules CO 2 ? 2.50 x 10 24 molecules CO 2 x 1 mole CO 2 6.02 x 10 23 molecules CO 2 = 4.15 mole CO 2

9 9 1. The number of atoms in 2.0 mole Al is A. 2.0 Al atoms. B. 3.0 x 10 23 Al atoms. C. 1.2 x 10 24 Al atoms. 2. The number of moles of S in 1.8 x 10 24 atoms S is A. 1.0 mole S atoms. B. 3.0 mole S atoms. C. 1.1 x 10 48 mole S atoms. Learning Check

10 10 Solution C. 1.2 x 10 24 Al atoms 2.0 mole Al x 6.02 x 10 23 Al atoms 1 mole Al B. 3.0 mole S atoms 1.8 x 10 24 S atoms x 1 mole S 6.02 x 10 23 S atoms

11 11 Subscripts and Moles The subscripts in a formula show the relationship of atoms in the formula. the moles of each element in 1 mole of compound. Glucose C 6 H 12 O 6 In 1 molecule: 6 atoms C 12 atoms H6 atoms O In 1 mole: 6 mole C 12 mole H 6 mole O

12 12 Subscripts State Atoms and Moles 9 mole C 8 mole H 4 mole O

13 13 Factors from Subscripts The subscripts are used to write conversion factors for moles of each element in 1 mole compound. For aspirin C 9 H 8 O 4, the following factors can be written: 9 mole C 8 mole H 4 mole O 1 mole C9H8O4 1 mole C9H8O4 1 mole C9H8O4 and 1 mole C9H8O4 1 mole C9H8O4 1 mole C9H8O4 9 mole C 8 mole H 4 mole O

14 14 Learning Check A. How many mole O are in 0.150 mole aspirin C 9 H 8 O 4 ? B. How many O atoms are in 0.150 mole aspirin C 9 H 8 O 4 ?

15 15 Solution A. How many mole O are in 0.150 mole aspirin C 9 H 8 O 4 ? 0.150 mole C 9 H 8 O 4 x 4 mole O = 0.600 mole O 1 mole C 9 H 8 O 4 subscript factor B. How many O atoms are in 0.150 mole aspirin C 9 H 8 O 4 ? 0.150 mole C 9 H 8 O 4 x 4 mole O x 6.02 x 10 23 O atoms 1 mole C 9 H 8 O 4 1 mole O subscript Avogadros factor Number = 3.61 x 10 23 O atoms

16 16 Chapter 10.2 Mole to Mass Relationships Molar Mass

17 17 Molar Mass The molar mass is the mass of one mole of an element or compound. is the atomic mass expressed in grams. Copyright © 2005 by Pearson Education, Inc. Publishing as Benjamin Cummings

18 18 Molar Mass from Periodic Table Molar mass is the atomic mass expressed in grams. 1 mole Ag 1 mole C 1 mole S = 107.9 g = 12.01 g = 32.07 g

19 19 Give the molar mass for each (to the tenths decimal place). A. 1 mole K atoms =________ B. 1 mol Sn atoms =________ Learning Check

20 20 Give the molar mass for each (to the tenths decimal place). A. 1 mole K atoms =39.1 g B.1 mole Sn atoms =118.7 g Solution

21 21 Molar Mass of a Compound The molar mass of a compound is the sum of the molar masses of the elements in the formula. Example: Calculate the molar mass of CaCl 2. ElementNumber of Moles Atomic MassTotal Mass Ca140.1 g/mole 40.1 g Cl235.5 g/mole 71.0 g CaCl 2 111.1 g

22 22 Molar Mass of K 3 PO 4 Calculate the molar mass of K 3 PO 4. ElementNumber of Moles Atomic MassTotal Mass in K 3 PO 4 K339.1 g/mole 117.3 g P131.0 g/mole 31.0 g O416.0 g/mole 64.0 g K 3 PO 4 212.3 g

23 23 Some One-mole Quantities 32.1 g 55.9 g 58.5 g 294.2 g 342.2 g One-Mole Quantities

24 24 What is the molar mass of each of the following? A. K 2 O B. Al(OH) 3 Learning Check

25 25 A. K 2 O 94.2 g/mole 2 mole K (39.1 g/mole) + 1 mole O (16.0 g/mole) 78.2 g + 16.0 g = 94.2 g B. Al(OH) 3 78.0 g/mole 1 mole Al (27.0 g/mole) + 3 mol O (16.0 g/mole) + 3 mol H (1.01 g/mole) 27.0 g + 48.0 g + 3.03 g = 78.0 g Solution

26 26 Prozac, C 17 H 18 F 3 NO, is an antidepressant that inhibits the uptake of serotonin by the brain. What is the molar mass of Prozac? 1) 40.1 g/mole 2) 262 g/mole 3) 309 g/mole Learning Check

27 27 Prozac, C 17 H 18 F 3 NO, is an antidepressant that inhibits the uptake of serotonin by the brain. What is the molar mass of Prozac? 3) 309 g/mole 17 C (12.0) + 18 H (1.01) + 3 F (19.0) + 1 N (14.0) + 1 O (16.0) = 204 + 18.2 + 57.0 + 14.0 + 16.0 = 309 g/mole Solution

28 28 Molar mass conversion factors are written from molar mass. relate grams and moles of an element or compound. Example: Write molar mass factors for methane, CH 4, used in gas stoves and gas heaters. Molar mass: 1 mol CH 4 = 16.0 g Conversion factors: 16.0 g CH 4 and 1 mole CH 4 1 mole CH 4 16.0 g CH 4 Molar Mass Factors

29 29 Acetic acid C 2 H 4 O 2 gives the sour taste to vinegar. Write two molar mass conversion factors for acetic acid. Learning Check

30 30 Acetic acid C 2 H 4 O 2 gives the sour taste to vinegar. Write two molar mass factors for acetic acid. Calculate molar mass: 24.0 + 4.04 + 32.0 = 60.0 g/mole 1 mole of acetic acid = 60.0 g acetic acid Molar mass factors 1 mole acetic acid and 60.0 g acetic acid 60.0 g acetic acid 1 mole acetic acid Solution

31 31 Molar mass factors are used to convert between the grams of a substance and the number of moles. Calculations Using Molar Mass Grams Molar mass factor Moles

32 32 Aluminum is often used to build lightweight bicycle frames. How many grams of Al are in 3.00 mole Al? Molar mass equality: 1 mole Al = 27.0 g Al Setup with molar mass as a factor: 3.00 mole Al x 27.0 g Al = 81.0 g Al 1 mole Al molar mass factor for Al Moles to Grams

33 33 Learning Check Allyl sulfide C 6 H 10 S is a compound that has the odor of garlic. How many moles of C 6 H 10 S are in 225 g?

34 34 Calculate the molar mass of C 6 H 10 S. (6 x 12.0) + (10 x 1.01) + (1 x 32.1) = 114.2 g/mole Set up the calculation using a mole factor. 225 g C 6 H 10 S x 1 mole C 6 H 10 S 114.2 g C 6 H 10 S molar mass factor (inverted) = 1.97 mole C 6 H 10 S Solution

35 35 Grams, Moles, and Particles A molar mass factor and Avogadros number convert grams to particles. molar mass Avogadros number g mole particles particles to grams. Avogadros molar mass number particles mole g

36 36 Learning Check How many H 2 O molecules are in 24.0 g H 2 O? 1) 4.52 x 10 23 2) 1.44 x 10 25 3) 8.03 x 10 23

37 37 Solution How many H 2 O molecules are in 24.0 g H 2 O? 3) 8.02 x 10 23 24.0 g H 2 O x 1 mole H 2 O x 6.02 x 10 23 H 2 O molecules 18.0 g H 2 O 1 mole H 2 O = 8.03 x 10 23 H 2 O molecules

38 38 Learning Check If the odor of C 6 H 10 S can be detected from 2 x 10 -13 g in one liter of air, how many molecules of C 6 H 10 S are present?

39 39 Solution If the odor of C 6 H 10 S can be detected from 2 x 10 -13 g in one liter of air, how many molecules of C 6 H 10 S are present? 2 x 10 -13 g x 1 mole x 6.02 x 10 23 molecules 114.2 g 1 mole = 1 x 10 9 molecules C 6 H 10 S

40 40 Chapter 10.2 Mole to Volume Volume and Moles (Avogadros Law)

41 41 Avogadro's Law: Volume and Moles In Avogadros Law the volume of a gas is directly related to the number of moles (n) of gas. T and P are constant.

42 42 The volumes of gases can be compared at STP, Standard Temperature and Pressure, when they have the same temperature. Standard temperature (T) 0°C or 273 K the same pressure. Standard pressure (P) 1 atm (760 mm Hg) STP

43 43 Molar Volume At standard temperature and pressure (STP), 1 mole of a gas occupies a volume of 22.4 L, which is called its molar volume.

44 44 Molar Volume as a Conversion Factor The molar volume at STP can be used to form conversion factors. 22.4 L and 1 mole 1 mole 22.4 L

45 45 Using Molar Volume What is the volume occupied by 2.75 moles N 2 gas at STP? The molar volume is used to convert moles to liters. 2.75 moles N 2 x 22.4 L = 61.6 L 1 mole

46 46 Guide to Using Molar Volume

47 47 A. What is the volume at STP of 4.00 g of CH 4 ? 1) 5.60 L2) 11.2 L3) 44.8 L B. How many grams of He are present in 8.00 L of gas at STP? 1) 25.6 g2) 0.357 g3) 1.43 g Learning Check


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