Chemical Quantities Unit
November 30-December 8 (2015)
Day 1: Formula Mass
Objectives (SWBAT):
Physical Science 41- Describe chemical quantities in terms of mass, particles, or moles
Inquiry 5- Convert from mass, particles, or liters to and from moles
Evaluated by:
-Gram Formula Mass Worksheet
-Naming Quiz Retake #2
Class structure:
Do Now: Name the compounds on the gram formula mass worksheet (or clear your desk if you are
required to take the 2nd Naming Retake Quiz).
1. Engage- Quick class review over the last unit (before Thanksgiving break)- IMF lab introduced
formula mass- redefine this term.
2. Explore- Students will calculate the formula mass for the compounds on the worksheet.
3. Explain- Students will show all work.
4. Elaborate- The teacher will introduce the idea that formula mass is really molar mass and use the
http://www.youtube.com/watch?v=1R7NiIum2TI video to define a mole.
Summary: Atoms are so small that it is impractical to talk about their properties (mass, volume, etc) on an
individual level. Instead, we talk about elements and compounds in units of moles (6.02x10^23 particles).
Day 2: Mole Conversions
Objectives (SWBAT):
Physical Science 41- Describe chemical quantities in terms of mass, particles, or moles
Inquiry 5- Convert from mass, particles, or liters to and from moles
Evaluated by:
Mole Conversions Packet (p. 50-53)
Class structure:
Do Now: Which is heavier- a molecule of CO2 or NO2?
1. Engage- The class will review the two definitions of a mole from Day 1 (molar mass and
Avogadro’s number) then the teacher will add the definition for the gas form (volume of 22.4
Liters) and use these to build a mole map.
2. Explore- Students will complete the 30 one-step mole problems using the mole map created
during the Engage.
3. Explain- Students will show all work.
4. Elaborate- Students will complete the last page of the packet with mixed one and two step mole
conversions.
Summary: One mole of a compound is by definition 6.02x10^23 particles of that compound that in gas phase
occupy 22.4L of space. This collection of particles has a unique mass based on the molar masses of the
component elements from the periodic table.
Day 3: Percent Composition
Objectives (SWBAT):
Physical Science 40- Calculate the percent composition of given compounds from formulas and from mass data
Inquiry 5- Use mathematics to solve problems
Evaluated by:
-Percent Composition Practice Sheet
-Naming Quiz Retake #3
Class structure:
Do Now: How many grams of CO2 are in 1.5x1025 molecules of CO2?
1. Engage- Students will write the formulas for the ten compound names on the practice sheet
while remaining students complete the naming quiz retake #3.
2. Explore- Students will pair/share answers to check their formulas then follow the steps of the
percent composition notes to determine the percent composition of each element in question
one.
3. Explain- The teacher will pause the class to complete the examples on the percent composition
notes page (1-3).
4. Elaborate- Students will complete questions 2-10 on their practice sheet.
Summary: Percent composition of an element (or substance) varies with different compounds and is important
in the real world of science because scientists try to use resources wisely, choosing compounds with a high
percentage of the element they need.
Day 4: Percent Composition Lab
Objectives (SWBAT):
Physical Science 40- Calculate the percent composition of given compounds from formulas and from mass data
Inquiry 5- Use mathematics to solve problems
Physical Science 41- Describe chemical quantities in terms of mass, particles, or moles
Evaluated by:
Percent Composition Lab
Class structure:
Do Now: Complete problem one on the back of day 3’s notes sheet.
1. Engage- Students will collect initial data for the lab then complete problems 2-5 on the back of
day 3’s notes sheet. (15 minutes)
2. Explore- Students will collect the final data for their lab.
3. Explain- Students will work in groups to answer the analysis and calculation questions in
complete sentences.
4. Elaborate- The teacher will explain why percent compositions are calculated in the real world
and how they are used with the second half of the notes page from day 3. Students will answer
questions 6-8 on the back of the notes page from day 3.
Summary: The percent composition of anything is part/whole *100. However, measured values and given
values do not always match in lab activities. This is due to a variety of reasons (called sources of error) and the
difference between the experimental result and true value is called percent error.
Day 5: Empirical Formulas
Objectives (SWBAT):
Physical Science 40- Determine the empirical formula for a compound from percent compositions
Inquiry 5- Use mathematics to solve problems
Evaluated by:
Start Empirical/Molecular Packet (10 questions)
Class structure:
Do Now: How many grams of carbon are in 100 grams of sugar (C6H12O6)?
1. Engage- NOTES: using percent compositions to find formulas (empirical formulas)
2. Explore- Students will complete the three questions on the back of the notes sheet alone as
practice.
3. Explain- Students will show all their work.
4. Elaborate- Students will determine the empirical formulas for all ten questions in the packet and
finish for homework if necessary.
Summary: The mole ratios determined by the percent composition represent the subscripts of the atoms
present in the empirical (experimentally determined) formula.
Day 6: Molecular Formulas
Physical Science 40- Determine the molecular formula for a compound from percent compositions and molar
mass
Inquiry 5- Use mathematics to solve problems
Evaluated by:
-Finish Empirical/Molecular Packet (10 questions)
-Putting it all together (Review)
Class structure:
Do Now: What is the empirical formula for a compound that is 80% Carbon and 20% Hydrogen?
1. Engage- NOTES: molecular formulas are multiples of empirical formulas
5. Explore- Students will complete the three questions on the back of the notes sheet alone as
practice.
6. Explain- Students will show all their work.
7. Elaborate- Students will determine the molecular formulas for questions 5, 6, and 9 in the
packet then begin reviewing for day 7’s test with the “putting it all together” worksheet.
Summary: The lowest whole number ratio determined by percent composition is used in the empirical formula
but with the additional information of molar mass, students can calculate the true (molecular) formula of the
compound.
Day 7: Test- Chemical Quantities
Objectives (SWBAT):
Physical Science 40 and 41, Inquiry 5- demonstrate at least 75% proficiency over the material of this unit
Evaluated by:
Test- Chemical Quantities
Class structure:
Do Now: Take out a calculator and something to write with, clear your calculator RAM, and move your
bags to the A/C
TEST
Summary: This is the last unit before the exam. Now is the time to begin reviewing old material because the
exam is cumulative (meaning you will be tested over material from the entire semester).
GLE
Objective
Day(s) Addressed
Inquiry 5
Utilize mathematics, organizational tools, and graphing skills to solve problems
1, 2, 3, 4, 5, 6
Physical
Science 40
Compute percent composition, empirical formulas, and molecular formulas of
selected compounds in chemical reactions
3, 4, 5, 6
Physical
Science 41
Apply knowledge of stoichiometry to solve mass/mass, mass/volume,
volume/volume, and mole/mole problems
1, 2, 4
Vocabulary
Molar Mass
Mole
Avogadro’s number
Empirical Formula
Molecular Formula
Equations/Constants
6.02* 1023 things= 1 mole
22.4 L of gas= 1 mole (at STP)
Percent composition= (mass of all atoms of an element in a compound/mass of compound) *100
Assessment Design- Unit 9
Basic: 6 Questions
Standard: 12 Questions
Expanded: 6 Questions
Essential Skills and Learning Objectives
Type of
Question
(MC, CR, P)
Basic
(Remember &
Understand)
Standard
(Apply &
Analyze)
Expanded
(Evaluate &
Create)
Compute percent composition of selected compounds in
chemical reactions
CR/ MC
2 MC
2 MC
2 CR
2 CR
Compute empirical and molecular formulas of selected
compounds in chemical reactions
CR/ MC
1 MC
1 CR
1 MC
3 CR
1 CR
1P
Apply knowledge of stoichiometry to solve mole/mass,
mole/volume, and mole/particle problems
CR/ MC
2 MC
4 CR
1 CR
1P