Honors Ch
hemistry 1 Te
erm B Antacid Sttoichiometry Lab Name: ________________________________ Date: _____
_______________ Hour: ________ Antacid SStoichio
ometryy STO.1 STO.3 STO.4 Balance a chemical equation. Define th
he purpose off stoichiomettry. Solve sto
oichiometric p
problems from
m a balancedd chemical equuation. Purpose: Use stoichiometry to dete
ermine the am
mount of calccium carbonaate in antacid tablets. Materialss:  Antacid Tabletts  Balance
 Hydrochloric A
Acid (HCl)  Graduateed Cylinder  25
50 mL (or largger) Erlenmeyyer flask Pre‐Lab: Sttomach acid iis a digestive fluid found in
n your stomacch that is useed by the body to break do
own food. The
e primary ingrredient in sto
omach acid is hydrochloricc acid (HCl). H
Heartburn is ccaused when some of the stomach aacid enters th
he esophagus and irritates the lining creeating an unccomfortable burning fe
eeling. One of the ove
O
er the counter treatments for heartbur n is a group o
of drugs comm
monly called Antacids. Antacids wo
ork by creating a chemical reaction to nneutralize thee stomach acid
d into ionic saalts, carbon dioxide and waater, therefore removing th
he source of tthe irritation. In
n this lab, you
u will use antaacid tablets co
ontaining calccium carbonaate to neutrallize a volume of HCl. You will measure the change in mass of the
e reaction to ddetermine th
he amount of carbon dioxid
de that is released. Then you will use sstoichiometryy to calculatee the amount of calcium caarbonate thatt was in each taablet or antaccid. Calcium ccarbonate reaacts with hyd rochloric acid
d to produce w
water, carbon dioxide gaas and dissolvved calcium chloride. 1. What causes h
W
heartburn? 2. How do antacids treat hearrtburn? 3. What safety co
W
oncerns are p
present in thiss lab and whaat safety preccautions need
d to be taken?? 4. Write a balanc
W
ced chemical equation including states of matter forr this reaction
n. Procedure
e: 1. Create a data ttable on a sep
parate sheet of paper to reecord all dataa from the lab
b. Make suree the taable can easily be read and
d include unitts for every n
number. 2. Gather your m
materials. Measure the maass of 2 antac id tablet(s) an
nd record thee mass in the data ta
able. 3. Measure out _
M
_____ mL of h
hydrochloric aacid and pourr this into a 250 mL Erlenm
meyer flask. Measure the m
M
mass of the flaask with the h
hydrochloric acid and reco
ord in the datta table. Sources: http
p://www.webmd.ccom/heartburn‐ge
erd/ http://www.ttums.com/heartbu
urn‐information.html www.123rf.com R
Revised for Honorss – Blake Winter 22014‐15 4. Calculate the starting mass by adding the masses of the tablets and your flask of acid and record in the data table. 5. Place 2 antacid tablets you massed into the flask containing the HCl and swirl until the tablet(s) have completely reacted. Try to get as many bubbles out of the solution as possible. Do not use a stirring rod because it will cause you to remove liquid and affect your results. 6. Measure the final mass of the solution and the flask and record in the data table. 7. Repeat Steps 1 – 5 for a second trial using the 2 new antacid tablets. Analysis Calculations: Show all calculations on the same piece of paper with your data table. 1. Using the Starting and Final Masses of the flask and the solution, determine what mass of carbon dioxide was produced by the reaction in each trial and record the mass in the data table for each trial. 2. Using stoichiometry, use the balanced equation from the pre‐lab and the mass of CO2 produced in each trial (2 separate problems) to calculate how many grams of calcium carbonate were used in each trial. Show your work on the paper with your data table. 3. Calculate the percent composition of calcium carbonate in your starting tablets. Show your work on the paper with your data table. Record in the Data Table. Percent Composition = mass of calcium carbonate ÷ total mass of tablet Conclusion: 1. Calculate the average amount of calcium carbonate in the one tablet from your trials. You will need to use this number in your conclusion. 2. The package claims that the tablets contain _______________ grams of calcium carbonate. Write a 6 – 8 sentence paragraph conclusion for this lab. The conclusion should include: a. A brief summary of the procedure for this lab (1 – 2 sentences). b. Restate the purpose for the lab in your own words (from the front). c. State your results for the amount of calcium carbonate in each antacid tablet and the percent composition of calcium carbonate in each tablet. d. Compare your results with the amount of grams of calcium carbonate per tablet from the package. e. Determine any sources of error that might have caused your results to be different from the amount on the package. (May not be human error, calculation error or significant figure error.) f. Discuss one new thing you learned from completing this lab. Post Lab Questions: Show all calculations on the same piece of paper with your data table. 1. Using your balanced equation, find out how many grams of HCl one tablet would need to completely react. 2. If you had 2.4 grams of calcium carbonate, how many grams of carbon dioxide would be produced?