Download Mole-Mass Conversions

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Chemistry 313
Chapter 12
CHEMICAL QUANTITIES
Chapter Outline
12.1  Counting Particles of Matter
Vocabulary
Mole
Avogadro’s constant
Molecule
Formula unit
Molar mass
Objectives
- Compare and contrast the mole as a number and the mole as a mass.
- Relate counting particles to weighing samples of substances.
- Perform mole, particle, mass and volume conversions
Term
Mole
Avogadro’s constant
Molar Mass
Molecule
Formula Unit
Definition
The unit of measure used to count atoms, molecule or formula units
The name assigned to the quantity 6.02 x 1023
The mass of one mole of a substance
The representative particle for a molecular compound
The representative particle for an ionic compound
Warm-up #1
Slide 3: Measuring Matter
What is a mole?
 The mole (mol) is the SI base unit used to measure the _________________________________.

1 mol = 6.02x1023 _______________________particles

6.02x1023 is called __________________number

Representative particles are the units used in these conversions

Atoms, formula units (_____________compounds), molecules (_______________________compounds)
Slide 4: Everything Leads to the Mole
Slide5: Mole to Particle Conversions
How many molecules of water are there in 2.4 moles of water?
How many moles of copper contain 3.5 x 1018 copper atoms?
Warm-up #2
Slide 7: Mass and the Mole

The mass of one mole of a substance is unique to that substance and is based on the sum of the
__________________________________ of the elements in that substance.

Mass of H2O = mass of __________hydrogen atoms + mass of __________oxygen atom
Slide 8: Calculating Molar Mass
 Elements
The molar mass of elements is equal to their _________________________ from the periodic table.
Example: 1 mole of Fe atoms = 55.847g
 Compounds
The molar mass of compounds is equal to the ___________ of the atomic masses of the individual elements in
that compound. Example: 1 mole of Fe2(SO4)3 = (2 x 55.847) + (3 x 32.066) + (12 x 15.999) = 401.662
Slide 9: Mole-Mass Conversions
 Unlike mole-particle conversions where the conversion factor is always 1mole = _______________ particles,
each mole-mass conversion factor is _________________ to the substance involved.
Convert 2.3 moles of sodium (Na) to grams of Na
Convert 10.0 g of CO2 to moles of CO2
Warm-up #3
Slide 11: Volume and the Mole
 According to Avogadro, the mass of _________mole of a __________at STP is always ____________, regardless
of the gas’ identity.
 STP = Standard Temperature and Pressure (____________and 1 ________)
Slide 12: Mole-Volume Conversions
How many moles of CO are contained in 1.8L of CO gas?
How many Liters of SO3 are represented by 0.5 moles of SO3 gas?
Slide 13: Multi-step Conversions
What is the mass of 1.0 x 1019 atoms of Aluminum?
Mole Conversions Worksheet
Mole-Particle Conversions
23
1 mol = 6.02 x 10 particles

  6.02 x1023 particles 
1 mole

 or 
Use: 
23
1 mole
 6.02 x10 particles  

1. How many moles of magnesium is 3.01 x 1022 atoms of magnesium?

1 mole

 = 5 x 10-2 moles
23
 6.02 x10 atoms 
3.01 x 1022 atoms 
2. How many molecules are there in 4.00 moles of glucose, C6H12O6?
 6.02 x1023 molecules 
 = 2.41 x 1024 molecules
1
mole


4.00 moles 
3. How many moles are 1.20 x 1025 atoms of phosphorous?
4. How many atoms are in 0.750 moles of zinc?
5. How many molecules are in 0.400 moles of N2O5?
6. How many moles are 1.2x 1018 water molecules?
Mole-Mass Conversions
1 mol = molar mass (periodic table)


 g  formula  mass 
1 mole
 or 

1 mole
 g  formula  mass 


Use: 
1. How many moles in 28 grams of CO2 ?
Molar mass of CO2 =( 1 x 12.01 g) + (2 x 16.00 g)= 64.00 g/mol
 1 mole 
 = 0.64 moles CO2
 44.00 g 
28 g CO2 
2. What is the mass of 5 moles of Fe2O3 ?
Gram-formula-mass Fe2O3
= (2 x 55.6 g) + (3 x 16.0 g) = 159.2 g/mol
 159.2 g 
 = 800 grams Fe2O3
1
mole


5 moles Fe2O3 
3. Find the number of moles of argon in 452 g of argon.
4. Find the grams in 1.26 x 10-4 mol of HC2H3O2.
5. Find the mass in 2.6 mol of lithium bromide.
6.
Find the number of moles of water molecules in 212g of water.
Mole-Volume Conversions
1 mol = 22.4 L for a gas at STP
Use:
 1 mole   22.4 L 

 or 

 22.4 L   1 mole 
1. Determine the volume, in liters, occupied by 0.030 moles of a gas at STP.
 22.4 L 
 = 0.67 L
1
mole


0.030 mol 
2. How many moles of argon atoms are present in 11.2 L of argon gas at STP?
 1 mole 
 = 0.500 moles
 22.4 L 
11.2 L 
3. How many moles of methane gas are there in 2.6L of methane at STP?
4. What is the volume of 1.2 moles of water vapor at STP?
5. How many moles of oxygen are there in 43.8L of oxygen at STP?
6.
What is the volume of 0.05 mol of neon gas at STP?
Mixed Mole Conversions
Given unit  Moles  Desired unit
1. How many oxygen molecules are in 3.36 L of oxygen gas at STP?
 1 mole   6.02 x1023 molecules 
 = 9.03 x 1022 molecules
 
3.36 L 
1 mole
 22.4 L  

2. Find the mass in grams of 2.00 x 1023 molecules of F2. 12.624 g
Molar-mass = 2 x 19 g = 38 g/mol
  38 g 
1 mole
 
 = 12.6 g F2
23
6
.
02
x
10
particles
1
mole




2.00 x 1023 molecules 
3. Determine the volume in liters occupied by 14 g of nitrogen gas at STP.
Ans. 11.2 L
4. Find the mass, in grams, of 1.00 x 1023 molecules of N2.
Ans. 4.65 g
5. How many particles are there in 1.43 g of a molecular compound with a gram
molecular mass of 233 g?
Ans. 3.69 x 1021
6. Aspartame is an artificial sweetener that is 160 times sweeter than sucrose (table sugar) when dissolved in water. It
is marketed by G.D. Searle as Nutra Sweet. The molecular formula of aspartame is C14H18N2O5 .
a) Calculate the gram-formula-mass of aspartame.
Ans. 294 g/mol
b) How many moles of molecules are in 10 g of aspartame?
Ans. 3.4 x 10-2 moles
c) What is the mass in grams of 1.56 moles of aspartame?
Ans. 458.64 grams
d) How many molecules are in 5 mg of aspartame?
Ans. 1.0238 x 1019
e) How many atoms of nitrogen are in 1.2 grams of aspartame?
Ans. 4.9143 x 1021
Homework #1
1.
What is the representative particles for the following substances ? (atoms, molecules, formula units)
a. Manganese
____________________
b. Calcium chloride
____________________
c. Carbon dioxide
____________________
2. Calculate the number of formula units in 0.35 moles of copper.
3. What is the molar mass of Al2(CO3)3?
4. How many moles are 22.5g of aluminum carbonate (Al2(CO3)3)?
5. What is the volume of 0.62 moles of nitrogen gas at STP?
6. How many silver atoms are here in 27.98g of silver?
7. How many liters are 2.3 x 1015 molecules of chlorine gas?