Ximena Delgado

Ms. Petty

Chemistry HL-Pd. 5

18/04/11

Aspirin Lab Report

Introduction

Aspirin is an acid. In order to make an aspirin there is a mix of salicylic acid and acetic anhydride with H2SO4.The synthesis of aspirin is an esterification, in other words it’s when an acid and an alcohol mix together in order to form a product  which in this case it’s an aspirin. However esterification is a reversible reaction. Different strengths of aspirin are based on the amount of active ingredients that they contain.

Titration is a way to determine how much acid is in a solution by adding just enough base of a known concentration to neutralize the acid. In neutralization, the number of moles of acid, H+, are combined with an equal number of moles of base, OH-. The aspirin will be titrated against a standard solution of base, 0.100 M NaOH. Base will be dispensed from a biuret into a beaker containing the dissolved (in ethanol) acid and phenolphthalein indicator, which will show a faint pink color in basic solutions. This range of colors determines the color change interval and it expresses the pH range.  Phenolphthalein indicator shows acid form when the color is clear and a base form when the color is pink. The approximate range of change in color is when the pH is 8 to 9.8.

 Purpose

The purpose of this lab is to experimentally determine the molar mass of pure aspirin(acetyl salicylic acid) present in an aspirin tablet using a titration.

Hypothesis

Variables

Dependent:

Independent:

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Procedure

Raw Data

Data Processing

Titration

Cardioton Trial 1

Mass of Aspirin:0.868

Volume of NaOH:

VI=27.51 mL                                            Vf=44.71 mL                                         Difference: 17.2 mL  

Titration Equation

0.0172L x 0.100M = 0.00172 moles of NaOH

Molar mass

C9=108.9 g

H9=9.09 g

O4=63.96 g

108.9 g + 9.09 g + 63.96 g = 181.96

181.96x

Uncertainties

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