Lab Report Analysis of an Antacid PDF

Preview

Summary

Download Lab Report Analysis of an Antacid PDF

Description

Analysis of an Antacid By: Jonathan Pilafas (performed on 10/15/2018)

Purpose: The objective of this lab is to compare different generic and name brand antacids to determine if they are equally effective in neutralizing acid and if they are comparably cost effective.

References: 1. “Laboratory Experiments for Chemistry 121” - Harper College 2. http://dept.harpercollege.edu/chemistry/msds1/Phenolphthalein%20JTBaker.pdf 3. http://dept.harpercollege.edu/chemistry/msds1/Hydrochloric%20acid%20Fisher.pdf 4. http://dept.harpercollege.edu/chemistry/msds1/Sodium%20hydroxide%20Fisher.pdf 5. http://dept.harpercollege.edu/chemistry/msds1/Calcium%20carbonate%20Fisher.pdf

Reagents: Name

Formula

Molecular Weight

Concentration

Hazards

Hydrochloric Acid

HCl

36.46 g/mol

36-38%

Health - 3 Fire - 0 Reactivity - 1

Sodium Hydroxide

NaOH

40.00 g/mol

50%

Health - 3 Fire - 0 Reactivity - 1

Phenolphthalein

C20H14O4

318.312 g/mol

N/A

Health - 2 Fire - 1 Reactivity - 0

Tums

CaCO3

Active Ingredient in Antacid

N/A

Health - 2 Fire - 0 Reactivity - 0

Methods: To begin the experiment, record the antacid brand name, the ingredients (active and inactive) in your antacid, the mass of the active ingredient, the price of the bottle, and the number of tablets in each bottle. Then, rinse the burets with deionized water and label them accordingly. Next, obtain two antacid tablets and find the mass of each of these. After this, obtain the HCl and NaOH solutions and record the molarities on the stock bottles. Next, put 15 25 mL of HCl solution into each of two clean Erlenmeyer flasks and record the exact volume of HCl used in each Erlenmeyer flask. Add one of the antacid tablets to each flask and heat gently for 1-2 minutes to help dissolve the tablets. Bring each solution to a boil to get rid of any undissolved carbon dioxide. After finishing this, allow the solution to cool. Once the solution is cool, add 2-3 drops of phenolphthalein to antacid mixture. Lastly, titrate each antacid mixture with the NaOH solution until you have reached the end point of the indicator used.

Balanced Chemical Equation: -

CaCO3(s) + 2HCl(aq) → CaCl2(aq) + H2O(l) + CO2(g)

-

NaOH(aq) + HCl(aq) → NaCl(aq) + H2O(l)

Calculations: -

Moles HCl initial = (0.2500 L HCl / 1) X (0.9936 mol HCl / 1 L HCl) = 0.02484 mol HCl initial

-

Moles HCl excess = (0.01500L NaOH / 1) X (1.082 mol NaOH / 1 L NaOH) X (1 mol HCl / 1 mol NaOH) = 0.01623 mol HCl excess

-

Moles HCl reacted (nH) = (0.02484 mol H+) - (0.01623 mol H+) = 0.00861 mol H+ reacted w/ antacid

-

Average mass of tablets: Mol HCl = 0.0086 mol reacted (nH / g) = 0.0086 mol / 1.161 g antacid = average mass of the tablets = 0.0074 g

-

nH/grams of antacid tablet: moles of H+ neutralized by antacid per gram of antacid tablet (nH/g) =

-

Average nH/grams = 0.0342 g

-

Standard Deviation nH/grams = 0.00045

-

Mass of Active Ingredient = (0.00861 mol HCl reacted / 1) X (100 g CaCO3 / 1 mol CaCO3) = 8.61 g CaCO3

-

Cost of antacid per gram of active ingredient in cents per gram: (599 cents / 1 bottle) X (1 bottle / 150 tablets) X (1 tablet / 0.475 g CaCO3) = 8.4 cents / 1g

Data:

[HCl] (concentration)

53%

[NaOH] (concentration)

23%

Trial Mass Antacid Tablet

Volume HCl

Moles HCl initial

Volume NaOH

Moles NaOH

Moles HCl unreacted

Moles HCl reacted with Antacid

1

1.353 g 4.679 g/mL

0.0032 mol

5.372 g/mol

0.0124 mol

0.00173 mol

0.0183 mol

2

1.354 g

3.937 g/mL

0.0013 5.374 mol g/mol

0.072 mol

0.00273 mol

0.0128 mol

3

1.353 g

3.284 g/mL

0.0183 5.273 mol g/mol

0.017 mol

0.0073 mol

0.0172 mol

4

1.362 g

3.283 g/mL

0.0033 4.926 mol g/mol

0.018 mol

0.00273 mol

0.0126 mol

Name of Active Ingredient

List brand name of antacid analyzed here.

Formula of Active Ingredient

Calcium carbonate

 CaCO3

Mass of active ingredient/tablet on label #tablets/bottle ¢/bottle

+

Trial

Moles H neutralized

nH/g (moles H+ neutralized per gram of antacid tablet)

Mass of Antacid Tablet

1 2 3 4 Average Standard Deviation

Discussion In paragraph format report the following (report actual values): 1. Name of antacid brand.

Cents/gram of active ingredient

Calculated Mass of active ingredient/tablet

2. Active ingredient in the antacid you analyzed. 3. nH/g (average moles of hydrogen ions neutralized per gram of active ingredient 4. Cents/gram of active ingredient 5. Compare the precision of your own trials with each other and with other members of your group. Account for differences. 6. Calculated Mass of active ingredient/tablet. (from your data) 7. Labeled mass of active ingredient. 8. Compare the calculated mass of active ingredient with the mass given on the antacid label. Account for differences. Is it higher or lower than the labeled mass? Explain. 9. Include class data in your report. a. Compare your results with other brands. i.e. class data. b. After all class data are tabulated, discuss which antacid you would buy and why. Are there other considerations besides cost and neutralizing ability to consider?

Conclusion...