UNIT 1: STOICHIOMETRY
Learning Outcomes: By the end of this unit, you will be able to:
Apply an understanding of the nature of chemical reactions in terms of atomic conservation to balance
chemical equations and calculate stoichiometric quantities, such as yields based on the limiting reagent.
Lesson 1: Chemical Reactions and the Mole Concept
At a molecular level, what occurs during a chemical reaction?
What underlying principle is used to balance chemical reactions?
Example Problem 1: Balance the following equations.
a.
b.
c.
Example Problem 2: Balance the following equation which involves carbonate and nitrate ions:
,Multiple Reactions
Watch the narrated slideshow: Multiple Reactions. After watching this video answer the following questions in
your own words:
Simultaneous reactions are ...
Sequential reactions
What incorrect assumption is being made when simultaneous reactions are added to write an overall reaction?
Can you combine sequential reactions to form an overall reaction?
Online Content Tip! After you start the slideshow, clicking the icon expands all slides.
Study Tip! Try each example problem independently first. When you get stuck watch the narrated solution once, then
try to solve the problem without referring to the provided solution.
Example Problem 3: How many molecules of nitric acid ( ) can be produced from each molecule of ammonia
using the following sequence of three reactions?
Are the reactions in Example Problem 3, sequential or simultaneous? How can you tell?
,The Mole Concept
A mole is
Why is it convenient to define the unit of quantity, mole?
is defined as
Calculations Involving Moles
1 CH4 molecule contains _______ C atoms and _______ H atoms.
1 mol CH4 contains _______ mol C atoms and _______ mol H atoms.
Important concept!
Example Problem 4: Isopentyl acetate (C7H14O2) is the compound responsible for the scent of bananas.
Interestingly, bees release about 1.0 µg of this compound when they sting, in order to attract other bees to join the
attack.
How many moles of isopentyl acetate are released in a typical bee sting?
How many atoms of carbon are present in this sample?
, Concept Check 1: Which of the following systems contains 20 mol of hydrogen atoms? Select all that apply.
4 mol ammonium hydroxide (NH4OH)
12 mol of hydrogen gas (H2)
5 mol of methane gas (CH4)
4 mol of ethanol (C2H5OH)
Concept Check 2: The hemoglobin content of blood is about 15.5 g/100 mL blood. The molar mass of hemoglobin
is about 64 500 g/mol. There are 4 iron (Fe) atoms in a hemoglobin molecule. Approximately how many grams of
iron are present in the 5.0 L of blood in a typical adult?
Mole Conversion
1 mol = _______ mmol 1 kmol = _______ mol 1 lb-mol = _________ mol
Note that these conversions are equivalent to the conversion between units of _______________!
Concept Check 3: How many atoms are there in 1.0 lb-mol of 12C?
Learning Outcomes: By the end of this unit, you will be able to:
Apply an understanding of the nature of chemical reactions in terms of atomic conservation to balance
chemical equations and calculate stoichiometric quantities, such as yields based on the limiting reagent.
Lesson 1: Chemical Reactions and the Mole Concept
At a molecular level, what occurs during a chemical reaction?
What underlying principle is used to balance chemical reactions?
Example Problem 1: Balance the following equations.
a.
b.
c.
Example Problem 2: Balance the following equation which involves carbonate and nitrate ions:
,Multiple Reactions
Watch the narrated slideshow: Multiple Reactions. After watching this video answer the following questions in
your own words:
Simultaneous reactions are ...
Sequential reactions
What incorrect assumption is being made when simultaneous reactions are added to write an overall reaction?
Can you combine sequential reactions to form an overall reaction?
Online Content Tip! After you start the slideshow, clicking the icon expands all slides.
Study Tip! Try each example problem independently first. When you get stuck watch the narrated solution once, then
try to solve the problem without referring to the provided solution.
Example Problem 3: How many molecules of nitric acid ( ) can be produced from each molecule of ammonia
using the following sequence of three reactions?
Are the reactions in Example Problem 3, sequential or simultaneous? How can you tell?
,The Mole Concept
A mole is
Why is it convenient to define the unit of quantity, mole?
is defined as
Calculations Involving Moles
1 CH4 molecule contains _______ C atoms and _______ H atoms.
1 mol CH4 contains _______ mol C atoms and _______ mol H atoms.
Important concept!
Example Problem 4: Isopentyl acetate (C7H14O2) is the compound responsible for the scent of bananas.
Interestingly, bees release about 1.0 µg of this compound when they sting, in order to attract other bees to join the
attack.
How many moles of isopentyl acetate are released in a typical bee sting?
How many atoms of carbon are present in this sample?
, Concept Check 1: Which of the following systems contains 20 mol of hydrogen atoms? Select all that apply.
4 mol ammonium hydroxide (NH4OH)
12 mol of hydrogen gas (H2)
5 mol of methane gas (CH4)
4 mol of ethanol (C2H5OH)
Concept Check 2: The hemoglobin content of blood is about 15.5 g/100 mL blood. The molar mass of hemoglobin
is about 64 500 g/mol. There are 4 iron (Fe) atoms in a hemoglobin molecule. Approximately how many grams of
iron are present in the 5.0 L of blood in a typical adult?
Mole Conversion
1 mol = _______ mmol 1 kmol = _______ mol 1 lb-mol = _________ mol
Note that these conversions are equivalent to the conversion between units of _______________!
Concept Check 3: How many atoms are there in 1.0 lb-mol of 12C?
