3A Mole of Atoms 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 1023 atoms of an element (Avogadro’s number).1 mole element Number of Atoms1 mole C = x 1023 C atoms1 mole Na = x 1023 Na atoms1 mole Au = x 1023 Au atoms
4A Mole of a Compound A mole of a covalent compound has Avogadro’s number of molecules.1 mole CO2 = x 1023 CO2 molecules1 mole H2O = x 1023 H2O moleculesof an ionic compound contains Avogadro’s number of formula units.1 mole NaCl = 6.02 x 1023 NaCl formula units1 mole K2SO4 = 6.02 x 1023 K2SO4 formula units
5Samples of One Mole Quantities 1 mole C = 6.02 x 1023 C atoms1 mole Al = 6.02 x 1023 Al atoms1 mole S = 6.02 x 1023 S atoms1 mole H2O = 6.02 x 1023 H2O molecules1 mole CCl4 = 6.02 x 1023 CCl4 molecules
6Avogadro’s Number Avogadro’s number 6.02 x 1023 can be written as an equality and two conversion factors.Equality:1 mole = x 1023 particlesConversion Factors:6.02 x 1023 particles and mole1 mole x 1023 particles
8Using Avogadro’s Number Avogadro’s number is used to convertparticles of a substance to moles.How many moles of CO2 are in2.50 x 1024 molecules CO2?2.50 x 1024 molecules CO2 x mole CO26.02 x 1023 molecules CO2= mole CO2
9Learning Check 1. The number of atoms in 2.0 mole Al is A Al atoms.B x 1023 Al atoms.C x 1024 Al atoms.2. The number of moles of S in 1.8 x 1024 atoms S isA mole S atoms.B mole S atoms.C x 1048 mole S atoms.
10Solution C. 1.2 x 1024 Al atoms 2.0 mole Al x 6.02 x 1023 Al atoms B. 3.0 mole S atoms1.8 x 1024 S atoms x mole S6.02 x 1023 S atoms
11Subscripts 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.GlucoseC6H12O6In 1 molecule: 6 atoms C 12 atoms H 6 atoms OIn 1 mole: 6 mole C 12 mole H 6 mole O
12Subscripts State Atoms and Moles 9 mole C 8 mole H 4 mole O
13Factors from Subscripts The subscripts are used to write conversion factors formoles of each element in 1 mole compound. For aspirinC9H8O4, the following factors can be written:9 mole C mole H mole O1 mole C9H8O mole C9H8O4 1 mole C9H8O4and1 mole C9H8O mole C9H8O mole C9H8O49 mole C mole H mole O
14Learning Check A. How many mole O are in 0.150 mole aspirin C9H8O4? B. How many O atoms are in mole aspirin C9H8O4?
15Solution A. How many mole O are in 0.150 mole aspirin C9H8O4? 0.150 mole C9H8O4 x 4 mole O = mole O1 mole C9H8O4subscript factorB. How many O atoms are in mole aspirin C9H8O4?0.150 mole C9H8O4 x 4 mole O x x 1023 O atoms1 mole C9H8O4 1 mole Osubscript Avogadro’sfactor Number= x 1023 O atoms
16Chapter 10.2 Mole to Mass Relationships Molar Mass
18Molar Mass from Periodic Table Molar mass is the atomic mass expressed in grams.1 mole Ag mole C mole S= g = g = g
19Learning CheckGive the molar mass for each (to the tenths decimal place).A. 1 mole K atoms = ________B. 1 mol Sn atoms = ________
20Solution Give the molar mass for each (to the tenths decimal place). A. 1 mole K atoms = 39.1 gB. 1 mole Sn atoms = g
21Molar 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 CaCl2.ElementNumber of MolesAtomic MassTotal MassCa140.1 g/mole40.1 gCl235.5 g/mole71.0 gCaCl2111.1 g
22Molar Mass of K3PO4 Calculate the molar mass of K3PO4. Element Number of MolesAtomic MassTotal Mass in K3PO4K339.1 g/mole117.3 gP131.0 g/mole31.0 gO416.0 g/mole64.0 gK3PO4212.3 g
24Learning Check What is the molar mass of each of the following? A. K2O B. Al(OH)3
25SolutionA. K2O g/mole2 mole K (39.1 g/mole) + 1 mole O (16.0 g/mole)78.2 g g = gB. Al(OH) g/mole1 mole Al (27.0 g/mole) + 3 mol O (16.0 g/mole)+ 3 mol H (1.01 g/mole)27.0 g g g = g
26Learning CheckProzac, C17H18F3NO, is an antidepressant that inhibits the uptake of serotonin by the brain. What is the molar mass of Prozac?1) g/mole2) 262 g/mole3) 309 g/mole
27SolutionProzac, C17H18F3NO, is an antidepressant that inhibits the uptake of serotonin by the brain. What is the molar mass of Prozac?3) 309 g/mole17 C (12.0) + 18 H (1.01) + 3 F (19.0)+ 1 N (14.0) + 1 O (16.0) == 309 g/mole
28Molar Mass Factors 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, CH4, used in gas stoves and gas heaters.Molar mass:1 mol CH4 = gConversion factors:16.0 g CH and mole CH41 mole CH g CH4
29Learning CheckAcetic acid C2H4O2 gives the sour taste to vinegar. Write two molar mass conversion factors for acetic acid.
30Solution Acetic acid C2H4O2 gives the sour taste to vinegar. Write two molar mass factors for acetic acid.Calculate molar mass:= 60.0 g/mole1 mole of acetic acid = g acetic acidMolar mass factors1 mole acetic acid and g acetic acid60.0 g acetic acid mole acetic acid
31Calculations Using Molar Mass Molar mass factors are used to convert between the grams of a substance and the number of moles.Molar mass factorMolesGrams
32Moles to Grams 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 = g AlSetup with molar mass as a factor:3.00 mole Al x g Al = g Al1 mole Almolar mass factor for Al
33Learning CheckAllyl sulfide C6H10S is a compound that has the odor of garlic. How many moles of C6H10S are in 225 g?
34Solution Calculate the molar mass of C6H10S. (6 x 12.0) + (10 x 1.01) + (1 x 32.1) = g/moleSet up the calculation using a mole factor.225 g C6H10S x mole C6H10S114.2 g C6H10Smolar mass factor (inverted)= 1.97 mole C6H10S
35Grams, Moles, and Particles A molar mass factor and Avogadro’s number convertgrams to particles.molar mass Avogadro’snumberg mole particlesparticles to grams.Avogadro’s molar massparticles mole g
36Learning Check How many H2O molecules are in 24.0 g H2O? 1) x 10232) x 10253) x 1023
37Solution How many H2O molecules are in 24.0 g H2O? 3) 8.02 x 1023 24.0 g H2O x 1 mole H2O x 6.02 x 1023 H2O molecules18.0 g H2O mole H2O= 8.03 x 1023 H2O molecules
38Learning CheckIf the odor of C6H10S can be detected from 2 x g in one liter of air, how many molecules of C6H10S are present?
39SolutionIf the odor of C6H10S can be detected from 2 x g in one liter of air, how many molecules of C6H10S are present?2 x g x mole x x 1023 molecules114.2 g mole= 1 x 109 molecules C6H10S
40Volume and Moles (Avogadro’s Law) Chapter Mole to VolumeVolume and Moles (Avogadro’s Law)
41Avogadro's Law: Volume and Moles In Avogadro’s Lawthe volume of a gas is directly related to the number of moles (n) of gas.T and P are constant.
42STPThe volumes of gases can be compared at STP, Standard Temperature and Pressure, when they havethe same temperature.Standard temperature (T)0°C or 273 Kthe same pressure.Standard pressure (P)1 atm (760 mm Hg)
43Molar VolumeAt standard temperature and pressure (STP), 1 mole of a gas occupies a volume of 22.4 L, which is called its molar volume.
44Molar Volume as a Conversion Factor The molar volume at STP can be used to form conversion factors.22.4 L and mole1 mole L
45Using Molar Volume What is the volume occupied by 2.75 moles N2 gas at STP?The molar volume is used to convert moles to liters.2.75 moles N2 x L = L1 mole