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Name of Partner 1 and Name of Partner 2
Experiment 1: Introduction to Glassware
DATE
1. The volume of water dispensed in each trial can be found in the table below. A
sample calculation is below the table.
Volume in Trial 1 (mL) Volume in Trial 2 (mL)
125 mL Erlenmeyer flask
100 mL beaker
10 mL graduated cylinder
50 mL graduated cylinder
10.00 mL volumetric flask
10.00 mL volumetric pipet
50.00 mL buret
SAMPLE CALCULATION (mass to volume using density)
2.
Measuring device or technique
Erlenmeyer
flask
100 mL
beaker
10 mL
graduated
cylinder
50 mL
graduated
cylinder
10.00 mL
volumetric
flask
10.00 mL
volumetric
pipet
Average
volume (mL)
Difference
(in mL) of two
samples
Percent
error (%)
Percent
Difference (%)
PERCENT ERROR SAMPLE CALCULATION
PERCENT DIFFERENCE SAMPLE CALCULATION
3. We found that the … was the most accurate at measuring 10.00 mL of water. We
believe this because …We found that the … was the most precise for measuring
10.00 mL of water. We believe this because…
50.00 mL
buret
Experiment 1
Introduction to Glassware
PURPOSE
Students will be able to…
● Identify various pieces of glassware and determine its proper use
● Make measurements with a variety of glassware and evaluate these
measurements and the precision of the glassware
Instructor Demo
Instructor Always
Personal Protective Equipment Requirements
Safety Glasses
X
Gloves Nitrile
X
Lab Coat
Gloves Heavy
Fume Hood
Bio Hood
BACKGROUND
There are various types of glassware found in the laboratory; some are designed to
contain liquids, while others are designed to deliver liquids, and still others are simply
for storage or mixing. Beakers and Erlenmeyer flasks are used ​only​ to store or mix
liquids, not for measuring.
“To contain” or TC glassware, such as a volumetric flask, is used when making
solutions as you need to have an ​exact volume of the final solution​. If you were to
pour out from this type of glassware there will be some liquid left in the container; so
you may only pour out 99 mL when you made 100 mL of solution.
“To deliver” or TD glassware, such as a graduated cylinder, pipet, or buret, is used to
deliver particular volumes of liquid. When you pour liquid from one container to another,
some liquid typically remains in the first container. TD glassware is calibrated to
account for this remaining liquid, so when you mark to the 100 mL line, you will pour out
100 mL.
Accuracy and precision are two terms that need to be considered when making
measurements. Accuracy refers to the closeness of a measured value to a standard
value. For example, if you find the mass for a given substance to be 3.2 kg, but the
actual mass is 10 kg, then your measurement is not accurate as your measurement is
not close to the known value. Precision refers to the closeness of two or more
measurements to each other. Using the example above, if you mass the substance five
times, and get 3.2 kg each time, then your measurement is very precise; however it is
not very accurate. You can also be accurate but imprecise. For example, if on average,
your measurements for a given substance are close to the known value, but the
measurements are far from each other, then you have accuracy without precision.
Within this experiment you will (a) identify glassware and the use of each piece of
glassware and (b) determine the accuracy and precision of various pieces of glassware.
1
MATERIALS–All glassware should be dry before use






5 – 125 mL Erlenmeyer Flasks
1 — 50 mL Erlenmeyer Flask
1 – 100 mL beaker
1 – 10 mL graduated cylinder
1 – 10.00 mL volumetric pipet
1 – 50.00 mL buret
● Top loader balance on each
bench
● Pipet bulbs (green)
Pre-Laboratory Assignment–to be completed and submitted to Moodle before lab
begins.
Understanding glassware
1. For each of the pictures below:
a. Identify the glassware (word bank below)
a. Graduated pipet, volumetric pipet, volumetric flask, Erlenmeyer flask,
graduated cylinder, buret, beaker
b. Determine if this glassware is used TC (“to contain”), TD (“to deliver”), or to
store/mix.
2
Procedure
Precision of Glassware (Flask, Volumetric pipet, graduated cylinder, beaker, and
buret)
1. Predict the rank order of precision (reproducibility–#1 being most precise and #5
the least) and accuracy (correctness–#1 being most accurate and #5 the least)
of the four types of glassware being used. Record in your notebook.
2. Label the 5 – 125 mL Erlenmeyer Flasks, 1-5.
3. Flask 1: ​50 mL Erlenmeyer Flask
a. Place flask 1 on the balance and tare (zero out) your balance. Remove
the flask from the balance. Using the graduation marks on the side of the
50 mL flask as your guide, add 10 mL of water from the 50 ml flask to flask
#1. Place flask #1 back on the balance and record this mass. Remove
the flask, and again using the graduation marks, add an additional 10 mL
of water to the flask that already has 10 mL of water in it. Place back on
the balance and record this second mass. (Think what the approximate
mass should be considering that the density of water is 1.0 g/mL)
4. Flask 2: ​100 mL Beaker
a. Place flask 2 on the balance and tare your balance. Remove the flask
from the balance. Using the graduation marks on the side of your 100 mL
beaker as your guide, add 10 mL of water to the beaker and then transfer
to flask 2. Place the flask back on the balance and record this mass.
Repeat again with an additional 10 mL of water, record the new mass.
5. Flask 3: ​10 mL graduated cylinder
a. Place flask 3 on the balance and tare your balance. This time, use your
10 mL graduated cylinder to measure 10 mL of water. Carefully measure
the sample by adding drops of water with a disposable pipet to the 10 mL
graduation mark. Pour the sample into the flask, place onto the balance
and record the mass. Measure another 10 mL of water in the 10 mL
graduated cylinder, add the water to the flask, and record the new mass.
6. Flask 4: ​10.00 mL volumetric pipet
a. Repeat everything you did with flask 3; however, this time use your 10.00
mL volumetric pipet to measure the two samples of 10 mL of water.
7. Flask 5:​ 50.00 mL buret
a. Place flask 5 on the balance and tare your balance. This time use a 50.00
mL buret to measure the two samples of 10 mL of water.
3
b. Data Table (record masses here)
Mass of 10 mL (g)
50 mL Erlenmeyer flask
100 mL beaker
10 mL graduated cylinder
10.00 mL volumetric pipet
50.00 mL buret
Mass of 20 mL (g)
ANALYSIS and DISCUSSION​ (use template found on Moodle)
1. Determine the volume of water dispensed in each trial by each piece of glassware
using the mass of the water (in g) and the assumption that the density of water is
1.00 g/mL. Show one sample calculation. ​NOTE: You are calculating the average
volume of the two trials.
2. Fill in the blanks on the table below. Show one sample calculation for percent error
(measure of accuracy) and one for percent difference (measure of precision).
Measuring device or technique
50 mL
Erlenmeyer
flask
100 mL
beaker
10 mL
graduated
cylinder
Average
volume (mL)
Difference
(in mL) of two
trials
Percent
error (%) (10
mL is
“theoretical”
(accuracy)
Percent
Difference
between 2
trials
(precision)(%)
4
10.00 mL
volumetric
pipet
50.00 mL
buret
P ercent Error =
|Actual−T heoretical|
T heoretical
x 100
Dif f erence in V olume
Average V olume
P ercent Dif f erence =
x 100
3. Which of these pieces of glassware was the most ​accurate​ at measuring 10.00 mL
of water? Most ​precise​? Explain your decision for each.
POST-QUESTIONS
1. You have 5.72 g of ethanol. The density of ethanol is 0.789 g/mL at 25 o​​ C.
a. What is the volume of ethanol (in mL)? Show final result with correct
number of significant figures.
b. You are asked to dispense the volume of ethanol found in part (a) with an
uncertainty of less than 0.05 mL. Which item should be used for this task
(Think back to your experimental results)? Explain your decision.
A. 10 mL volumetric flask
B. 10 mL volumetric pipet
C. 25 mL buret
D. 10 mL graduated cylinder
2. You have access to a 25.00 mL volumetric pipet, a 25.00 mL volumetric flask, and a
25 mL graduated cylinder.
a. Which of these pieces of glassware would you want to use if you want a final
solution​ volume of 25.00 mL (note the implied precision)? Explain your
decision.*
b. Which would you use if you wanted to ​add​ 25 mL of ethanol to a solution?
Explain your decision.*
*Note: Be sure to discuss TC and TD within your answers to these questions.
3. Can you have a set of experimental data that is ​precise​ but not ​accurate?​ Give an
example and explain.
4. I want to make a fortune synthesizing a new COVID-19 vaccine. Is it critical that I am
precise in my dosage or might something else be more crucial from a medical
standpoint? Explain.
5
Experiment 2
Models, Models Everywhere
A lesson on Modeling
PURPOSE
Students will be able to…
● Describe the use of models in science and explain that there are a variety of
different types of models
● Discuss the limitations of models and how these limitations can be taken into
account when using models to learn
● Determine the number of valence electrons, draw Lewis structures, and
determine the electron and molecular geometry of various molecules
BACKGROUND
Models are a vitally important aspect of science. The following excerpts from Daly
(2010) note the importance of models in science
“They provide access to realms of science that are difficult or impossible to access
otherwise. They offer opportunities to consider scientific phenomena from a variety of
perspectives—e.g. they can be scaled up or scaled down, they can emphasize certain
aspects over others, and they can represent function. Models translate ideas into organized
products that can focus, develop, and challenge understandings” (p. 76).
“Models can translate abstract ideas, represent systems or objects that are difficult to see,
and summarize information in cohesive ways. Models can be used to allow students to see
things they otherwise could not, including both scaled-up and scaled down views (Duit,
1991). Models can be extractions of a larger concept or system, highlighting an important
aspect of it (Gilbert, 1993)” (p. 77).
In this experiment, you will investigate several different types of models. You will begin
with models showing the development of the model of the atom over time. Then, you
will examine different models of molecules ranging from pictures on paper to computer
simulations.
PRE-LAB
1. Determine the type of bonding (ionic or covalent or both) in each of the following:
a. NaCl
e. NH4+
f. NaF
b. CH3OH
c. Cl2
g. MgCO3
d. H2O
h. AlCl3
2. How many valence electrons are around each of the following atoms?
a. Hydrogen
d. Oxygen
b. Nitrogen
e. Chlorine
c. Carbon
f. Chloride
g. Sodium
h. Sodium ion
3. Do all atoms end up with an octet when bonded in a neutral molecule? FInd 2
examples (molecules where one or more atoms do not have an octet) and explain
why that occurs.
4. What are isomers? GIve an example
MATERIALS
None needed
PROCEDURE
A: Understanding Models
1. Examine the following computer models that you can access via links listed
below. Then answer the Analysis and Discussion questions for Part A. In this
section, you should be thinking about what is a model, why we use models in
science, what limitations exist, and what makes a “good” model.
a. 3D models on computer
(http://phet.colorado.edu/en/simulation/molecule-shapes)
b. computer simulation to build molecules
(http://phet.colorado.edu/en/simulation/build-a-molecule)
B: Creating Molecular Models
1. For the molecules listed below you need to:
a. Determine the number of valence electrons for all atoms
b. Draw ALL possible Lewis structures
i. The central atom is the least electronegative atom (remember how
to tell electronegativity by using a periodic table)
ii. You may find some isomers as you are drawing. Isomers are
molecules with the same molecular formula, but different chemical
structures meaning they have the same atoms, but they are just
arranged differently in space.
c. Determine the electron and molecular geometry (use chart on next page)
(VSEPR–Valence Shell Electron Pair Repulsion)
VSEPR #
(# of
bonding
areas)
2
Electron Geometry
Linear
Electron
Distribution
Molecular
Geometry
2 bonded pairs
0 lone pairs
Linear
3D Shape
Trigonal planar
3 bonded pairs
0 lone pairs
Trigonal planar
2 bonded pairs
1 lone pair
Bent
4 bonded pairs
0 lone pairs
Tetrahedral
3 bonded pairs
1 lone pair
Trigonal pyramidal
2 bonded pairs
2 lone pairs
Bent
5 bonded pairs
0 lone pairs
Trigonal bipyramidal
4 bonded pairs
1 lone pair
See-saw
3 bonded pairs
2 lone pairs
T-shaped
2 bonded pairs
3 lone pairs
Linear
6 bonded pairs
0 lone pairs
Octahedral
5 bonded pairs
1 lone pair
Square pyramidal
4 bonded pairs
2 lone pairs
Square planar
3
Tetrahedral
4
Trigonal bipyramidal
5
Octahedral
6
ANALYSIS and DISCUSSION
A: Understanding Models
1. Critique the computer simulations. What aspects do you think are accurate and
what aspects of the models do you think are not accurate?
2. Are models useful if they are not completely accurate? Is there a benefit to
seeing more than one model of a molecule? Explain your reasoning.
3. If you were helping someone learn the structure of a molecule, which model or
models would you choose? Why?
B: Creating Molecular Models
Electron Geometry: __________________
1. Molecular Formula: NCl3
Number of valence electrons: _____ Molecular Geometry: _________________
Lewis Structure:
2. Molecular Formula: NH4+
Electron Geometry: __________________
Number of valence electrons: _____ Molecular Geometry: _________________
Lewis Structure:
3. Molecular Formula: H3O+
Number of valence electrons: _____
Lewis Structure:
4. Molecular Formula: N2
Number of valence electrons: _____
Lewis Structure:
Electron Geometry: __________________
Molecular Geometry: _________________
Electron Geometry: __________________
Molecular Geometry: _________________
5. Molecular Formula: NO2
Electron Geometry: __________________
Number of valence electrons: _____ Molecular Geometry: _________________
Lewis Structure:
6. Molecular Formula: CO2
Electron Geometry: __________________
Number of valence electrons: _____ Molecular Geometry: _________________
Lewis Structure:
7. Molecular Formula: C2H4O
Number of valence electrons: _____
Lewis Structure:
8. Molecular Formula: C2H2Br2
Number of valence electrons: _____
Lewis Structure:
9. Molecular Formula: H2O2
Number of valence electrons: _____
Lewis Structure:
10. Molecular Formula: XeF4
Electron Geometry: __________________
Number of valence electrons: _____ Molecular Geometry: _________________
Lewis Structure:
11. Looking back at the molecules that you have constructed and drawn above,
which molecule(s) was an isomer? How do you know? Describe an isomer.
12. Looking back at the molecules that you have constructed and drawn above,
which molecules are polar and which are nonpolar? Explain your decision.
13. Why do NO2 and CO2 have different molecular shapes (See your results above),
even though their molecular formula is so similar?
POST-QUESTIONS
1. Are the following statements true or false? Explain why.
a. All atoms in a molecule will have a full shell when bonded.
b. Electron geometry and molecular geometry can never be the same.
c. There can never be more than eight electrons around a single atom in a
molecule.
d. It is possible to draw more than two structures (Lewis structures) from a given
molecular formula
2. For the following molecules determine:
a. Number of valence electrons
b. Electron Geometry (Pick one central atom to do this)
c. Molecular Geometry
d. ALL Possible Lewis structures (identify any isomers)
i. BeCl2
ii. PCl5
iii. CH2O
iv. C2H2
v. AlCl3
REFERENCES
Daly, S. (2009). Tall, Short, Thick, and Thin: They’re all Models. NCLT Purdue University
Professional Development Program.
Daly, S. and Bryan, L. (2010). Model Use Choices of Secondary Teachers in Nanoscale
Science and Engineering Education. Journal of Nano Education, 2, 76-90.
Experiment 4
Bigger Bang for your Buck:
A lesson on Limiting Reactants
Personal Protective Equipment Requirements
Safety guidelines due to Covid-19 have to be followed at all times!
Instructor Demo
Safety Glasses X Gloves Nitrile
X Fume Hood
Instructor or
X
Lab Coat
Gloves Heavy
Bio Hood
Assistant Always
Present
PURPOSE
Students will be able to…
• Determine a limiting reactant, explain how to determine a limiting reactant, and
explain how the limiting reactant influences the reaction
• Determine the amount of CO2 produced, theoretically and actually, in each
reaction and explain why these values differ based upon the reaction
• Determine the percent yield of CO2
BACKGROUND
Gastric acid in the stomach, which is primarily hydrochloric acid, HCl(aq), has a pH
between 1 – 3. This low pH is needed to aid in the digestion of food. However,
sometimes there is too much acid produced in the stomach
which can cause us to become uncomfortable and
experience heartburn. To alleviate this condition, many
people take antacids. Some common antacids are AlkaSelzer which contains sodium bicarbonate as the active
ingredient, and Tums, Rolaids, and Maalox tablets which all
contain calcium carbonate as the active ingredient. These antacids work by neutralizing
the excess acid in the stomach and therefore relieving the pain associated with an
increase in acid concentration. In this experiment you will investigate the concept of
limiting reactants using the active ingredients found in these different types of antacids.
PRE-LAB
1. You want to make 250.00 mL of a 0.500 M HCl solution from stock HCl which is 12.1
M.
a. Show the math to determine volume of stock needed. (Remember the dilution
equation: M1V1 = M2V2)
b. With this number, write a mini-procedure to prepare your 0.500 M solution.
Remember to specify what type of glassware is needed for each step (think back
to Experiment #1)
1
2. Write the complete (include state symbols: s, l, g, aq), balanced molecular equation
for the following reaction: solid aluminum carbonate reacts with aqueous
hydrochloric acid to form gaseous carbon dioxide, aqueous aluminum chloride, and
liquid water
3. Write the complete (include state symbols), balanced molecular equation for the
following reaction: solid sodium hydrogen carbonate reacts with aqueous
hydrochloric acid to form gaseous carbon dioxide, aqueous sodium chloride, and
liquid water.
4. What safety hazards are present when dealing with HCl? Does it matter if it is 12.1
M or 0.500 M? Explain.
MATERIALS
• Netbook
• 7 balloons (on each bench)
• 7 – 125 mL Erlenmeyer flasks
• Sodium Hydrogen Carbonate
(One bottle on each bench)
• Spatula






1.00 M hydrochloric acid (100 mL
per student group)-Bottle on each
bench
Distilled water
10.00 mL pipette
Pipettor (green)
Top loader balance
Plastic funnel
PROCEDURE
Reacting Sodium Hydrogen Carbonate with 10.00 mL Hydrochloric Acid
1.
2.
3.
4.
5.
6.
7.
8.
Stretch out the 7 balloons.
Transfer 10.00 mL of 1.00 M hydrochloric acid to each flask using a pipette.
Weigh each flask with the hydrochloric acid added.
Measure 0.15, 0.35, 0.50, 0.70, 1.00, 1.35, and 1.70 g of sodium hydrogen
carbonate and transfer to each balloon (record actual masses of sodium
hydrogen carbonate used).
Carefully stretch each balloon over the mouth of the flask without dropping in the
powder.
Drop the powder into the acid by lifting the balloon and let the reaction begin.
Observe the flasks and balloons. Think about what observations are needed. A
ruler may be of assistance. Record your observation in your notebook.
After reaction finishes and you have made your observations, remove the
balloons, swirl the flasks again to make sure the reaction has gone to completion,
and reweigh each flask. You shoul …
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