How many eggs are there in 5
dozen?
How many moles are in 2.25 grams
of the element iron, Fe?
Standard: Utilize appropriate
mathematical equations and
processes to solve chemistry
problems. 3221.Math.1
Objective: The learner will convert
the amount of a substance by using
molar conversions through
dimensional analysis.
Introduction to the Mole
What is a mole?
Mole – SI base unit used to measure the
amount of a substance
What is molar mass?
Molar mass – the mass in grams of one mole
of a substance (ex. hydrogen 1.0079g/mol)
What is the conversion factor for molar
mass?
1 mole= mass of an atom (mass number)
Practice
What is the number of moles found in 50.4
grams of Uranium?
Calculate the number of moles of 80.850 g of
nitrogen.
Calculate the number of moles in 334 grams
of lead.
Moles to Grams
6.0 moles carbon= __________ grams carbon
4.5 x 103 moles K = ___________ grams K
Determine the mass in grams of 19.73 moles of
the element boron, B.
8.90 mol Ca = ___________ g Ca
2.8 mol Fe = ___________ g Fe
4.59 x 102 mol F = _____________ g F
6.000 mol S = ____________ g S
PROVE IT!!!!!!!
5.68 g N= ___ mol N
0.405 mol N
0.0821 mol Rb= ___ g Rb
7.02 g Rb
3400 g O= ___ mol O
210 mol O
34.71 mol As= ___ g As
2600. g As
Exit slip
Determine the number of moles of
46.3 grams of the element, copper,
Cu?
Evaluate and explain in words how
you solve this problem. Tell me step
by step in complete sentences (4 to 5
sentences).
Homework
What is the mass in grams of .375 mol of the
element potassium, K.
What is the mass in grams of 0.0135 mol of the
element, sodium, Na?
How many moles of gold, Au, are in 3.6 x 10-10 g
How many moles of copper, Cu, are in 3.22g of
copper?
Standard: Utilize appropriate
mathematical equations and
processes to solve chemistry
problems. 3221.Math.1
Objective: The learner will convert
the amount of a substance by using
Avogadro’s number through
dimensional analysis.
Avogadro’s Number and Molar
Conversions
Avogadro’s
Number
Avogadro was born in
Italy from 1776-1865
His field of study was
physics.
He developed
Avogadro’s number
which is 6.022 x 10 23
6.022 x 1023 = 1 mol
Moles to Avogadro’s Number
0.30 mol of F = ______ atoms F.
2.66 mol of N= ______ atoms N?
How many atoms are in 4.2 mol O?
Avogadro’s Number to Moles
6.7 x 1026 atoms of Zn= _______ moles Zn
1.69 x 1023 atoms of V= _______ moles V?
How many moles are in 3.29 x 1021 atoms Al?
Practice Please !!!!!!
0.187 mol Ca = _________ atoms Ca
How many atoms are in 1.45 x 10-17 moles of As?
5.00 x 1021 atoms of S = __________ moles S
How many moles of neon are in 7.60 x 1024
atoms?
PROVE IT!!!!!!!
5.68gN=__mol N
0.0821 mol Rb=__g Rb
0.187molCa=__atoms Ca
7.60 x 1024Ne atoms=___ moles Ne
Exit Slip
How many moles are in 4.5 x 1024 atoms of
Ni?
How many atoms are 78.94 moles of iodine?
HOMEWORK!!!!!
Page 86 Practice Problems 1-3.
Write the questions and show your work.
Standard: Utilize appropriate
mathematical equations and
processes to solve chemistry
problems. 3221.Math.1
Objective: The learner will convert
two step molar conversions. The
learner will calculate the molecular
weight of a compound, and apply it
to molar conversions.
Entrance Slip
Find the mass in grams of
3.012 x 1024 atoms of Ca. The
molar mass is 40.08 g/mol
Converting Grams to atoms
Example:
1. Calculate the number of atoms in a 356 g
sample of Ti?
2. Determine the number of atoms in 7.60 g
of He.
3. 841 g Mn = __________ atoms of Mn
Converting Atoms to Grams
Example:
1. Find the mass in grams of 2.44 x 1024
atoms of carbon, whose molar mass is
12.01 g/mol.
2. Find the mass in grams of 2.11 x 1024
atoms of copper, whose molar mass is
63.55g/mol.
3. 5.46 x 1024 atoms Pb = __________g Pb
Mole Relay Race
Student #1- Read the problem and set the
problem up for the correct number of
steps.
Student #2- Place the units in the set up.
Student #3- Fill in the correct conversion
factors.
Student #4- Solve and write the answer
with the correct number of sig. figs.
Exit Slip
4.06 x 1024 atoms Cu = _______ g Cu
702 grams P = ________ atoms P
Molar Conversion 2- Step
Homework
1. Determine the number of moles of fluorine in 9.23 x 10-9
g of fluorine.
2. How many atoms of germanium are in 3.00 x 106 g Ge?
3. What is the mass in grams of 1.2 x 1025 atoms of the
element bromine, Br?
4. How many atoms of beryllium are in 1.67 x 103 g of Be?
5. What is the mass in grams of 9.70 x 1023 atoms of
magnesium, Mg?
Molecular Weight
What is the molecular weight of
HCl?
Molecular weight
Molecular weight – the mass in grams of one
moles of a substance. (g/mol)
What is the molecular weight of the following:
NaCl
H2 O
Ca(NO3)2
Mg(NO3)2
How many moles are in 67.68
grams of Al2S3?
345.0 grams of NaOH= ________ mol of NaOH
5.6 moles of HBr= _______ grams of HBr
200.5 grams of MgCl2 = _______ mol of MgCl2
4.5 moles SiCl4 = _____ molecules SiCl4
2.3 moles of CaS = _______ formula units CaS
Determine the number of moles of F2 in 5.6 x
1023 molecules of F2.
Exit Slip
How many grams are in 8.9 moles of Li2O?
How many molecules are in 5.90 moles of CO?
267 grams of LiBr = ______ formula units LiBr
7.8 x 1024 molecules of CO2 = _____ grams of CO2
149.0 grams of OF2 = ______ molecules OF2
HOMEWORK
Determine the mass in grams of 89.0 moles of NaNO3?
6.00 grams of B2(SO4)3= ____ formula units of B2(SO4)3
7.8 x 1024 formula units of Ba3P2 = ____ moles of Ba3P2
5.6 x 1025 formula units V3(PO4)5= _____ grams V3(PO4)5
Standard: Convert among the
following quantities of a substance:
mass, number of moles, and
number of particles.
Objective: The learner will review
molar conversions.
Fine the molecular weight of
potassium chlorate.
What is the mass in grams of 2.50
moles of oxygen, O2?
Ibuprofen, C13H18O2, is the active ingredient in
many nonprescription pain relievers. Its molar
mass is 206.31 g/mol.
a. If the tablets in a bottle contain a total of 33
grams of ibuprofen, how many moles of
ibuprofen are in the bottle?
b. How many molecules are in the bottle?
c. What is the total mass of carbon in 33 grams
of ibuprofen?
How many moles are there in 6.60 grams of
(NH4)2SO4?
How many grams of nitrogen is in 6.60 grams of
ammonium sulfate?
How many grams of oxygen are in 6.60 grams of
ammonium sulfate?
Practice Problems
How many grams of Al are in 43.8 g of Al2S3?
How many grams of chlorine are there in 0.35
moles of CH2Cl2?
What is the mass of chlorine in 3.36 grams of
MgCl2?
What is the mass of phosphorus in 135.0 grams
of K3PO4?
How many grams of nitrogen are in 2.01 moles
of N2O5?
Let’s RACE
Mole Relay Race
1. Read the problem and set the
problem up for the correct number of
steps.
3. Place the units in the set up.
4. Fill in the correct conversion factors.
5. Solve and write the answer with the
correct number of sig. figs.
Exit Slip
How many grams of phosphorus
are in 1.02 moles of Ca3(PO4)2?
Homework
How many grams of hydrogen are
there in 4.5 g of Ca(OH)2?
How many grams of carbon are there
in 3.4 grams of C12H22O11?
How many grams of nitrogen are in
0.35 moles of Cu(NO3)2?
Standard: Analyze ionic and
covalent compounds in terms of
percent composition.
Objective: The learner will evaluate
the percentage composition of
atoms in chemical formulas.
In what subjects would you most
likely use percentages?
Percentage Composition
Percentage
Composition
What is percentage
composition?
the percent by
mass of each
element in a
compound
Percentage Composition
What is the equation for percentage composition?
(Number of atoms of an element)(molar mass) X 100 = % of element
Molecular weight of the compound
in compound
Percentage Composition
Example 1: Find the percentage composition of copper sulfide, Cu2S.
Step 1: Write the equation.
Step 2: Choose one element to solve.
Step 3: Count the number of atoms that the element has. Substitute that
number into the equation.
Step 4: Find the molar mass of the element. Substitute that number into the
equation.
Step 5: Calculate the molecular weight of the compound. Substitute that number
into the equation.
Step 6: Solve
Step 7: Check your work by adding the percentages. Your final answer should be
at least 100%
Problem
Calculate the percentage composition of the
(NH4)2CO3.
Calculate the percentage composition of sodium
nitrate, NaNO3.
Calculate the percentage composition of calcium
hydroxide, Ca(OH)2
Rally Coach
Group 1: Calculate the percentage composition of Ag2SO4.
Group 2: Calculate the percentage composition of Cu(NO3)2.
Group 3: Calculate the percentage composition of NaCl.
Group 4: Calculate the percentage composition of FeSO3.
Group 5: Calculate the percentage composition of CaCO3.
Group 6: Calculate the percentage composition of H2S.
Group 7: Calculate the percentage composition of MgF2.
Student A: Calculate the percentage composition of
Ag2SO4.
Student B: Calculate the percentage composition of
Cu(NO3)2.
Exit Slip
Calculate the percentage composition of Al2S3.
Classwork
Write the statement. FIVE POINTS will be deducted is
the statements are not written. TEN POINTS will be
deducted if work is not shown.
Calculate the percentage composition of SrBr2.
Calculate the percentage composition of CaSO4.
Calculate the percentage composition of Mg(CN)2.
Calculate the percentage composition of Pb(NO3)2.
Calculate the percentage composition of Fe(MnO4)3.
Standard: Convert percentage
composition into an empirical
formula.
Objective: The learner will
investigate empirical formulas.
Empirical Formula
Formulas and Percentage
Composition
Empirical formulas- a chemical formula that
shows the composition of a compound.
(ratios of atom)
Determine Empirical Formulas from
Percentage Composition
1. Percent to mass (grams)-Assume that you
have 100g of the substance.
1. Mass (grams) to mole
1. Divide by the least number of moles.
1. Multiply 'til whole
Determine Empirical Formulas from
Percentage Composition.
Example
1. Chemical analysis of a liquid shows that it
is 60.0% C, 13.4 %H, and 26.6% O by mass.
Calculate the empirical formula of this
substance.
2. A dead alkaline battery is found to contain
a compound of Mn and O. Its analysis
gives 69.6% Mn and 30.4% O.
Determine Empirical Formulas from
Percentage Composition.
1. A compound is 38.77% Cl and 61.23% O.
2. A liquid compound is 18.0 % C, 2.26% H,
and 79.7% Cl.
Determine Empirical Formulas from
Percentage Composition
Exit Slip.
1. A compound contains 5.88%
hydrogen and 94.12% oxygen. What
is the empirical formula?
Determine Empirical Formulas from
Percentage Composition Homework.
1. A compound is made up of 92.3%
carbon and 7.7% hydrogen. What is
the empirical formula?
2. A compound contains 70.0% iron
and 30.0% oxygen. What is the
empirical formula?
Standard: Convert empirical
formulas to molecular formulas.
Objective: The learner will
investigate molecular formulas.
Molecular Formula
Determine Molecular Formulas from
Empirical Formula.
Molecular formula- a chemical formula that
shows the number and kinds of atoms in a
molecule.
Steps
1. Write the information that is given.
2. Find the molar mass of the empirical formula.
3. Solve using this formula.
n= experimental molar mass of compound
molar mass of empirical formula
4. Multiply the empirical formula by n to get the
molecular formula.
Determine Molecular Formulas from
Empirical Formula.
Example:
•The empirical formula for a compound is P2O5.
Its experimental molar mass is 284 g/mol.
Determine the molecular formula of the
compound.
• Determine the molecular formula of a
compound with an empirical formula of NH2 and
a molar mass of 32.06 g/mol.
Determine Molecular Formulas from
Empirical Formula.
Example:
•A sample with a formula mass of 34.00 g/mol is
found to consist of 0.44g H and 6.92g O. Find its
molecular formula.
•A compound with formula mass of 42.08 g/mol
is found to be 85.64% carbon and 14.36%
hydrogen by mass. Find its molecular formula.
Determine Molecular Formulas from
Empirical Formula.
•A compound has an experimental molar mass of 78
g/mol. Its empirical formula is CH. What is its
molecular formula?
•A compound has the empirical formula CH2O. Its
experimental molar mass is 90.0 g/mol. What is its
molecular formula?
• If 4.04g of N combine with 11.46g O to produce a
compound with a formula mass of 108.0 g/mol, what
is the molecular formula of this compound?
Determine Molecular Formulas from
Empirical Formula.
Exit Slip
Determine the molecular formula of a
compound with an empirical formula of C2H4S
and a formula mass of 179 g/mol.