CHM256 EXP 5 LAB Report PDF

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FACULTY OF APPLIED SCIENCEINDUSTRIAL HYGIENE & SAFETY TECHNOLOGY(AS121)BASIC ANALYTICAL CHEMISTRY (CHM 256)LABORATORY REPORT EXPERIMENT 5Acid-Base Titration II:Determination the Percent (w/w) of the Active Ingredient in Aspirin TabletPREPARED BY:NAME STUDENTS NUMBERAHMAD ASYRAF BIN AZAHAR 202089...

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FACULTY OF APPLIED SCIENCE INDUSTRIAL HYGIENE & SAFETY TECHNOLOGY (AS121) BASIC ANALYTICAL CHEMISTRY (CHM 256)

LABORATORY REPORT EXPERIMENT 5 Acid-Base Titration II: Determination the Percent (w/w) of the Active Ingredient in Aspirin Tablet PREPARED BY:

NAME

STUDENTS NUMBER

AHMAD ASYRAF BIN AZAHAR

2020893168

AISYA MADIHA BINTI KHAIRUL FAUZEE

2020488842

AIN NABILA BINTI SHAHARUDDIN

2020826702

NOR IZZATI BINTI ZAINAL ABIDIN

2020861336

Group : AS121 2B(1) Date of Experiment : 4 May 2021 Date of Submission : 24 June 2021 Prepared for : Pn. SITI MUNIRAH MUDA

INTRODUCTION

- Aspirin is a pain reliever that also helps to cool the body. The active ingredient in aspirin tablets is acetyl-salicylic acid (ASA) (CH3COOC6H4COOH). The alkaline fluids in the intestines hydrolyze aspirin into ethanoate and salicylate ions, whereas the acidic conditions in the stomach pass it unaltered. Aspirin overdose can end in death. For direct titration, many reactions are sluggish or have a weak equilibrium. Aspirin is a weak acid that hydrolyzes slowly because each molecule interacts with two hydroxide ions. To address this problem, a known excess of base is given to the sample solution, and the quantity of unreacted base is measured using an HCl titration. The quantity of aspirin in the analyte is calculated by subtracting the amount of base that actually interacted with the aspirin from the initial amount of base.

OBJECTIVE - To determine the percent (w/w) of the active ingredient, acetylsalicylic acid (C9H8O4) in aspirin tablets.

APPARATUS -

Volumetric flasks: 250 mL(1) 100 mL(2)

-

Retort stand

-

250 mL conical flask(x3)

-

20 mL , 25 mL pipette

-

Burette

-

Weighing boat/bottle/paper

-

Filter tunnel

-

Dropper

CHEMICALS -

1M NaOH - 50 mL or 100 mL (shared)

-

Indicator: Phenol red or phenolphthalein

-

Aspirin tablet (300 mg ASA)

-

0.1M HCL (250 mL)

PROCEDURE

a) Hydrolysis of aspirin

1. Number aspirin tablets weighed no more than 1.5kg. The brand name, the

manufacturer name, and % mass of the active ingredients in the tablet were recorded. 2. The aspirin tablet is weighed accurately in a weighing paper and transferred into a

250 ml conical flask. 3. 25 ml NaOH solution and 25 ml of water were added using a pipette to the tablet. About 10 minutes the mixture is heated until it boils in order to hydrolyze the aspirin. 4. The solution is cooled at room temperature then transferred into a 250 ml volumetric flask. The solution is diluted to the mark using a dropper when the level reaches close to the calibration mark Equation: Na2CO3 + 2HCL → 2NaCl + H2O + CO2

b) Back titration

1. 20ml of aspirin solution is pipetted into a 250ml conical flask. 2. Then, 1-2 drops of phenol red or phenolphthalein as an indicator were added 3. The aspirin solution is titrated in the 250 ml conical flask with HCl solution from the burette and continuously shaking the flask until the color changes. 4. The titration is repeated and all the data were recorded in the table. 5. The % w/w of the acetylsalicylic per tablet is calculated.

RESULTS / DATA

TABLE 5.1 commercial /brand name of aspirin tablet

millisprin

Name of manufacturer

KCK Pharmaceuticals 900 mg

Mass tablet of active ingredient (acetylsalicylic acid) stated on the label (2 tablet) Mass of aspirin tablet (2 tablet)

1.1567g

Calculated % w/w

77.8%

Table 5.2: Standardisation of HCL Solution

Titration

Rough

1

2

3

Final burette reading

23.73

23.70

23.70

23.80

Initial burette reading

0.00

0.00

0.00

0.00

Volume of HCL used

23.73

23.70

23.70

23.70

Average volume of HCL: 23.73mL Volume of Na2CO3 used: 25.00mL Molarity of Na2CO3 : 0.05M

Table 5.3: Titration of Aspirin Solution with HCL

Titration

Rough

1

2

3

Final burette reading

13.37

13.90

13.10

13.10

Initial burette reading

0.00

0.00

0.00

0.00

Volume of HCL used

13.37

13.90

13.10

13.10

Average volume of HCL: 13.37mL Initial volume of NaOH used to hydrolyze aspirin : 25.00mL

DISCUSSION

i)

The weight per tablet found as a result of the experiment is 0.721 g, which differs from the weight per tablet indicated by the manufacturer on the label, which is 1.1567 g. That is, there is a 19.89% discrepancy between the quantity measured and the amount stated by the manufacturer.

ii)

The aspirin tablets may include several acids and it is possible that the aspirin will not completely dissolve in the distilled water. The aspirin solution might not be well mixed. When the endpoints are close to reach, additional drops of hydrochloric acid may be added. The accurate estimate of 0.005 cm3 from the burette is difficult to achieve.

iii)

Instrument error because there may be faulty equipment or uncalibrated weight and glassware.

iv)

The accuracy of the experiment to measure aspirin concentrations is quite difficult due to the presence of acid impurities in aspirin tablets. Acetylsalicylate ions are esters produced when acids and alcohols are combined. Alcohol will be produced by reacting an ester with sodium hydroxide, NaOH. To determine the alcohol concentration, a distillation process will be used and as a result, the aspirin concentration can be determined.

v)

Precautions; All of the materials in this experiment are totally not too harmless. Aspirin obtained in the lab can not be tasted. Sodium hydroxide solutions are corrosive. The use of eye protection is recommended for all experimental procedures especially during heating and titration. After finishing the experiment, we must wash our hands even while doing the experiment using a glove. Remark; make sure to label sodium hydroxide and hydrochloric acid because they are colorless.

CONCLUSIONS -

The amount of acetylsalicylic acid in an aspirin tablet was determined in this experiment. The goal of this experiment is to ascertain the percent (w/w) of the active component, acetylsalicylic acid (ASA), in aspirin tablets,which was expected to be somewhat different from the amount on the table. This hypothesis is supported by a 19.89 percent difference between the quantity measured and the amount on the bottle.

QUESTIONS a) Based on the data obtained in table 5.2 calculate the exact molarity of HCl

b) Using back titration method, calculate the %w/w aspirin in the aspirin tablet.

vi)

Calculate the initial mole of NaOH used for hydrolysis.

vii)

Based on Equation (2), calculate the mole of excess (unreacted) NaOH.

viii)

Calculate the mole of NaOH that has actually reacted with acetylsalicylic acid.

ix)

Based on Equation (1), calculate the mole of acetylsalicylic acid in the solution.

x)

xi)

Calculate the mass then the %w/w of acetylsalicylic acid in the tablet.

Compare the %w/w calculated in table 5.1 and the result obtained in (e). Calculate the error.

REFERENCES 1) IsaacsTEACH. (2012, April 29). Chemistry 12.6b Calculating Titration [VIDEO] Youtube; https://www.youtube.com/watch?v=eoTmRK6sjTA 2) Carrie Miller, (August 2014). Chemistry Lab Report Guidelines. https://www.apu.edu/live_data/files/288/chemistry_lab_report_guidelines.pdf 3) College . Bellevue. (2014). Aspirin Tablet Titration.

https://www.bellevuecollege.edu/wpcontent/uploads/sites/140/2014/06/aspirin_tablets_titration.pdf...