Chemistry Final Project
Due Date: The Monday before Finals
I. INTRODUCTION:
This project is a synthesis of most of the material that we have learned throughout the course of
this year. It is somewhat open-ended and its concepts demonstrate the heart of what you have
learned.
A. Problem:
Determine the percentage (by mass) of calcium carbonate in "Tums" antacid.
B. Supplies Needed (per group)
1. Two 20-oz screw cap beverage containers for storing solutions. (clean and dry water
bottles work well)
2. One container of WHITE "Tums" antacid (I should have enough for everyone).
3. One gallon of distilled water (buy at grocery store).
 As a note: Several groups could purchase together a bottle of "Tums" One
container is enough for three to four groups of students.
C. Basic Chemistry:
"Tums" antacid contains many ingredients. One of those ingredients is calcium
carbonate, the same chemical that makes up the structure of human bones and seashells.
You will do three complimentary experiments to determine the percent by mass of
calcium carbonate in a "Tums" tablet. Those experiments are: Simple Weight Loss
Gasemetric, and Titrimetric.
D. Part 1: Simple Weight Loss
The student will react the "Tums" with excess of 3-M HCl. Assume that all mass lost is
due to the gas given off.
___CaCO3(s) + __HCl(aq)
___CaCl2( ) + ___CO2( ) + __H2O( )
E. Part 2 Gasemetric Method
The student will react 3-M hydrochloric acid with a crushed up "Tums" tablet, and
collect the gas.
F. Part 3: Titrimetric Analysis
Since calcium carbonate is a base, an acid can be added to reach the endpoint of the
reaction. But due to insolubility of the calcium carbonate, a technique called "back
titration will be utilized. You will need to add an excess amount of acid to the powder
(This amount will need to be known exactly). Then you will add sodium hydroxide to
the bromphenol blue endpoint. The solution will be cloudy due to the undissolved
particles but you need to get the solution to turn slightly blue)
 As a note: You will need to make up the following solutions:
 About 500 mL of about 0.2M HCl
 About 500 mL of about 0.2 M NaOH
II. WRITTEN REPORT
This report does not need to be typed, but will be able to use the computer lab on Friday and next
Monday if needed. It is recommended, but not required, that graphs are computer generated
using Excel. Each group of 2 people will prepare one report. I have lab notebooks if you want
to use these for this project.
A. Title Page
Partner names, teacher, date, and class period.
B. Table of Contents:
This table should include page references for each section of each different lab as well as
an introduction (general discussion) and final conclusion.
C. Each of the laboratory procedures will be written with the following parts (DO
THIS FOR ALL THREE SEPARATE LABS):
1. Procedure:
Describe in detail with diagrams (These may be hand drawn) what it is that you did
physically in the lab. Do not write this in prose form, but rather list each step that you
went through. It is advisable that you do as many trials as you deem necessary in
order to have statistical certainty.
2. Data Tables:
Include any relevant tables where data was collected. Missing data will result in a
deduction of points.
3. Calculations:
(a) Include all work that was done. This includes dimensional analysis,
stoichiometric calculations, gas laws, etc.
(b) Where possible, compare the theoretical value to what you believe to be the actual
value. Included all calculations and data to support your assertion as the
percentages.
Cause
4. Error Discussion:
A cause-effect error is required for each experiment. It should take the form of a
cause and effect table as seen below:
Effect
 The Effect should describe the possible effect on the FINAL result/number
obtained from the procedure. (too high, too low because…)
 Comment on which source of error is the most significant and why that source
of error is most significant
5. Results of this procedure.
(a) Summarize the results of this procedure. What is the "answer" for this part of the
procedure?
D. General Discussion of Chemistry Concepts Involved: (This is to be the most involved
portion of the write up. Your interview will consist of questions primarily from this
section)
Discuss all chemical principles that we have learned this year that apply to this
particular problem and the three procedures. Include diagrams and charts where
applicable. Each section should contain a subsection for each of the applicable
procedures done in the laboratory and a list of key words and their definitions. This
section will include the following topics. Please number the sections as follows.
1. Lab Specific Questions:
(a) Simple weight loss:
1) What main chemistry principle is fundamental to this procedure?
2) How can you tell if you have added excess acid (how can you tell if all of the
calcium carbonate reacted)?
3) What is the balanced chemical reaction involved in this procedure?
4) Using a solubility table, what are the states of the products formed in this
reaction?
5) Why should you tip the beaker or blow into the beaker after the reaction is
complete?
6) Is the HCl that is used a strong acid or a weak acid? Explain what a strong or
weak acid is in your answer?
7) Based on the concentration of your HCl, calculate the pH of the acid you used.
(b) Gas collection:
8) Which temperature did you record and why?
9) Why was a barometer necessary to complete the calculations?
10) Why did you equalize the pressures using the big bucket of water?
11) Why was water used in this procedure (give practical reasons)?
12) What was the gas that you collected?
13) Draw the Lewis structure of CO2 and determine its polarity.
14) Discuss the solubility of CO2 in water (is it soluble, how would temp change
the solubility, etc.) and how that could affect your results.
(b) Titrametric analysis (forward and reverse):
15) Why was it necessary to standardize both your acid and base (we may not do
this step, but still answer the question)?
16) Why is it important to accurately measure the amount of HCl added to the
Tums?
17) Why is it important to add excess HCl to the Tums?
18) In a titration, what two things are always equal to each other at the endpoint?
19) How did you determine the amount of acid (total) in the procedure?
20) How did you determine the amount of base (total) in the procedure?
21) Describe how you determined to prepare your 0.2 M solutions of HCl and
NaOH?
22) Why is it possible to add DI water to the solid acid without affecting your
results?
23) What is an indicator? List at least 2 indicators you have used in this class and
tell what colors they are in acidic and basic solutions.
2. General Chemistry Laboratory Questions:
(c) Acid/Base Chemistry:
24) Discuss in detail neutralization reactions and give at least one example
25) What is an acid, and what are the properties of an acid? Name and give the
chemical formulas for ALL the strong acids.
26) What is a base, and what are the properties of a base? Name and give the
chemical formulas for ALL the strong bases.
27) Water is considered amphoteric. What does “amphoteric” mean?
(d) Solution formation and solvation:
28) Discuss the process of solvation in terms of solute and solvent and the forces
that act to dissolve a soluble substance. Include an illustration or diagram.
29) Discuss the concept of concentrations in terms of molarity and give a specific
example. (What does molarity mean? A 2.5 M NaOH solution means…)
30) Why does HCl dissolve completely in water?
31) How could you speed up the process of solvation of a solute in a solvent?
(how would you speed up the dissolving of sugar to make sweet tea?) Discuss
this in terms of the KMT of solid/liquids/gases.
32) What is a solute? Give an example of two solutes from the lab.
33) What is a solvent?
34) What was our main solvent in this laboratory, and discuss why it was able to
dissolve the NaOH, and the HCl. Why was it incapable of dissolving the CaCO3?
(e) Bonding and forces of attraction:
35) Make a list of all the chemicals in this project. Identify the different types of
bonds in each chemical (ionic or covalent)?
36) Draw the Lewis Dot Structures for 3 chemicals involved in this project.
37) Write electron configurations (1s2,etc.) for all elements in calcium carbonate.
38) Which part of an atom is transferred to change its charge?
39) What is electronegativity? Describe the electronegativity differences in one of
the following species: hydrochloric acid, hydroxide anion, and sodium
chloride. How does this affect the solubility of these substances in water (is an
electronegativity difference related to polarity)?
40) When talking about Lewis dot structures, what is resonance? Do any of the
chemicals in this lab have resonance structures?
41) Sodium hydroxide exhibits both ionic and covalent bonding. Explain why.
42) Is water polar or non-polar and why?
(f) Limiting and Excess Reactants:
43) How can you determine which reactant is excess, which is limiting? (both
qualitatively and quantitatively)
44) If you have 3 tablets of TUMS and 30mL of 3.0 M HCl, how many liters of
gas could you produce at STP. Must show work.
(g) Gas Laws: Applies only to Gas Collection method
45) Discuss which gas laws were utilized and how they were utilized in the
experiment.
46) What gas or gases were present in the eudiometer (aka…an upside down
graduated cylinder) after performing the gas collection procedure?
47) What is Dalton’s Law of Partial Pressure? Why was this law important in the
gas collection procedure?
48) Explain, in terms of KMT, what happens to the collected gas as it cools in the
collection device for a period of time.
49) What is the ideal gas law equation? What do each of the variables stand for?
(h) Types of chemical reactions: (Single replacement, decomposition, etc.)
50) Write all balanced equations used in the project including states of matter,
identify which type of reaction it is, and write the names below all formulas in
each chemical reaction.
51) What is the difference between a complete ionic and net ionic equation?
(h) Law of Conservation of Matter and equilibrium:
52) Explain the law of Conservation of Matter
53) Discuss in detail the connection between the Law of Conservation of Matter
and the Simple Weight Loss procedure.
54) What is Le Chatelier's principle?
55) Around to Le Chatelier’s principle, if we removed the water from the simple
weight loss lab, in which direction would the reaction shift? What if we
increased the pressure?
This section is the most important part of your project. The difference between an
outstanding paper and an average paper is:
 the depth to which a group discusses each of these points
 the ability to distinguish between the central concepts in Chemistry and
those supporting concepts in each of the above mentioned areas.
D. CONCLUSION (the shortest part):
1. Final answer:
What is the final answer to your percentage?
2. Discussion of specific procedures:
Assess which procedure you think is the best method of determining which alkali
carbonate that you have. You should consider things such as accuracy, time, and cost
in your discussion.
III. Cheating:
Each PAIR needs to do their own report. Copying things from other students is not
acceptable and will be met with severe consequences. You will probably not pass Chemistry
with out a completed project.
IV. Grading Rubric:
Categories
Format and Presentation
Laboratory Reports
General Chemical Discussion
Conclusion
Section
Topic
Percentage
12 %
12 % x 3
40 %
12 %
Pt
Format
Lab Report x 3
Points
+30
(FOR EACH of THE 3 LABS)
Procedure
Data
Calculations
Error
Conclusion
+6
+5
+10
+6
+3
+30 x 3
Discussion
(Are questions answered
correctly?)
Simple Weight Loss
Gas Collection
Titration
Acid-Base
Solutions
Bonding/Attraction
Limiting and Excess Reagents
Gas Laws
Types of Reactions
Conservation of
Mass/Equilbrium
+10
+10
+10
+10
+10
+10
+10
+10
+10
+10
+100
Conclusion
Answer
Discussion of Procedures
+15
+15
+30
OVERALL
+250