unit v: the mole concept v.3. multiple conversions between moles, mass, volume and number of...
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Unit V: The Mole Concept
V.3. Multiple Conversions between Moles, Mass, Volume and Number of Particles
THE MIGHTY MOLE DIAGRAM
THE MIGHTY MOLE DIAGRAM
moles molecules atoms
L@STP
grams
Mighty Mole QuestionsGrams to Molecules conversion How many molecules are in a 2.62 g sample
N2O4
Plan: g mol molecules
1.71 x 1022 molecules
Mighty Mole QuestionsMolecules to Litres Conversion Find the volume occupied by 1.204 x 1026
molecules of SO2 at STP? Plan: molecules moles L
4480 L
Mighty Mole QuestionsGrams to Atoms Conversion Find the total number of atoms in a 300.0 g
glass of water. Plan: g mol molecules atoms date leaves
3.01 x 1025 atoms
Mighty Mole QuestionsGrams to Molecules 0.0342 g CH4 = ? Molecules Plan: grams moles molecules
1.29 x 1021 molecules
Mighty Mole QuestionsLitres to Molecules Conversion 54.3 L of NO2 = ? Molecules
1.46 x 1024 molecules
Mighty Mole QuestionsMolecules to Grams Conversion Find the mass of 3.68 x 1025 molecules of
NO2 (g)?
2.81 x 108 grams
Mighty Mole QuestionsMolecules Litres (STP) Conversion 1.35 x 1026 molecules of NH3 = ? L at STP
5.03 x 103 L
Mighty Mole QuestionsGrams to Atoms Conversion Find the number of atoms in a 286.0 g
sample of C3H8?
4.30 x 1025 atoms
Mighty Mole Questions
Find the number of “O” atoms in a 60.0L sample of N2O4
6.45 x 1024 “O” atoms
Hebden
Do Exercises 22 (a); 23 (a-d); 24 on pages 86-87 of Hebden
Do Exercises 36 (a); 37 (a) ; 38 (c); 42 (b, h, m) on pages 88-89 of Hebden
Assignment #9
DENSITY AND MOLES
Density is the mass per unit of volume
M
D V
THE MIGHTY MOLE DIAGRAM
moles molecules atoms
L@STP
grams
Density of Gases at STP
Density STP =
DSTP
Mass of 1 mole
Volume 1 mole
= Molar Mass
22.4
= MM (g/mol)
22.4 (L/mol) FOR FOR GASES GASES ONLYONLY
Density of Gases at STP
Find the density of P2O5 gas at STP?
DSTP
6.34g/L
= MM (g/mol)
22.4 (L/mol)
Density of Gases at STP
Calculate the density of O2 (g) at STP? DSTP
1.43 g/L
= MM (g/mol)
22.4 (L/mol)
Density of Gases at STP
The density of air is about 1.29 g/L. What is the density of Cl2 (g) at STP?
DSTP
3.17 g/L so Cl2 (g) is more dense than air
= MM (g/mol)
22.4 (L/mol)
Molar Mass From Density at STP DSTP = MM (g/mol)
22.4 (L/mol)
MM = DSTP x 22.4
Molar Mass From Density at STP An oxide of chlorine has a density of 3.013
g/L at STP
1. Find the molar mass of this gas
2. Determine the molecular formula for this gas
MM = DSTP x 22.4
Molar Mass From Density at STP An oxide of chlorine has a density of 3.013
g/L at STP
6.75 g/mol
MM = DSTP x 22.4
Molar Mass From Density at STP
ClO
ClO2
ClO3
Molar Mass From Density at STP A mystery gas has a density of 1.696 g/L at
STP. It is an element.
1. Find it’s molar mass
38.0 g/mol
MM = DSTP x 22.4
Molar Mass From Density at STP Given the molar mass of 38.0 g/mol
Guess the gas
Density of Solids and Liquids
M
D V
WHAT TO DO WHEN YOU DON’T HAVE A GAS!!
M = D x V
THE MEGA MIGHTY MOLE DIAGRAM
moles molecules atoms
L@STP
gramsD x V
M
D V
Example:Density Molecules Conversion The density of Boron (solid) is 2.34 g/mL. How many
molecules are there in a 60.0 mL chunk of boron? Plan: D x V g mol molecules
7.83 x 1024 molecules of Boron
ExampleAtoms Volume Conversion Liquid mercury has a density of 13.55 g/mL. Find the
volume occupied by 1.806 x 1027 atoms. (Hg is monatomic)
Plan: atoms molecules mol g volume
44413 mL or 44.4L
ExampleMoles Density Conversion A 5.00 mL sample of solid lead is known to contain 0.274
moles of Pb. Calculate the density of Pb. Plan: mol g density
11.35 g/mL
Example:Density MM (STP) 250.0 mL of a gas which is known to be a fluoride of
sulphur has a mass of 1.63 g at STP a) Find the molar mass
146.0g/mol
ExampleDensity MM (STP)(b) What is the molecular formula for the gas. (Calculated
Molar Mass = 146.0g/mol – fluoride of sulphur)
SF6 = 146.1 g/mol
ExampleD MM (STP) 1.25 L of disilane gas has a mass of 3.47 g. What is the
molar mass? (Assume STP) Plan: Density MM
62.2 g/mol
Example Density MM (STP) It is found that a 0.0263 mole sample of gas occupies a
volume of 482.0 mL. Calculate the molar volume in L/mol.
18.33 L/ mol
Hebden
Do Exercises 25, 27, 28 and 29 on pages 88 of Hebden Do Exercises 40 (e), 41 (a, f, h, k), 42 (b, e, n) on pages
89 of Hebden Do Hand-In Density Worksheet
Mid-Unit Test
Mega Mighty Mole Diagram Mole Conversions
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