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The aim of the experiment is to find the relative formula mass of an unknown acid in an acid solution that I was provided.

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Introduction

Table of contents 1.1 Aim of the experiment 2 1.2 Introduction 2 1.3 Equipments and apparatus 2 1.4 Safety precautions 2 2.1 Procedure 3 2.2 Apparatus setup 3 2.3 Analysis 4 3.1 Implementing 5 3.2 Analyzing 6 4.1 Evaluation 8 4.2 Comparison between experimental Mr with value 8 of likeliest acid 4.3 Conclusion 8 THE RELATIVE FORMULA MASS OF AN UNKNOWN ACID 1.1 Aim of the experiment The aim of the experiment is to find the relative formula mass of an unknown acid in an acid solution that I was provided. 1.2 Introduction I was provided with a solution of a monobasic (monoprotic) acid. Monoprotic acid is an acid that contains only one hydrogen atom. I was to determine the molarity of the acid by titration with a sodium hydroxide solution, and then use this molarity to calculate the relative formula mass of the acid. An acid is a substance that releases hydrogen ions when dissolved in water. There are two types of acids called organic acids and mineral acids. Organic acids, such as methanoic acid, citric acid or latic acid, are obtained from plant and animal sources. From the other side, mineral acids (hydrochloric acid, nitric acid or sulphuric acid) are made from minerals. ...read more.

Middle

3. Compare your calculated Mr value with the Mr value of likeliest acid. Calculate the percentage difference between these two values. 3.1 Implementing 1. Wash all the equipments used in the experiment (including burette, conical flask, pipette, pipette filler and beaker) with distilled water in the wash bottle. 2. Use pipette to transfer 25 cm3 of sodium hydroxide (alkali) solution into a conical flask. 3. Add 3 or 4 drops of phenol red indicator to the conical flask into which NaOH solution was put. 4. Fill the burette by pipette filler with acid solution up to point 0.00. 5. Take the point at which level of acid solution is least as the initial reading. Wash the side of conical flask during the titration. 6. Swirl the solution in the conical flask for the indicator to disperse evenly and continue swirling while adding the acid solution from the burette as well. 7. Start adding acid solution drop wise from the burette carefully to be able to stop adding acid solution at a correct point when the endpoint is reached. 8. When the purple colour starts to change to yellow, stop adding acid solution. This is the endpoint. 9. Read correctly the final reading of volume on the burette when the endpoint is reached. ...read more.

Conclusion

/ 250 = � 0.2% 3. The percentage maximum error in use of burette Burette � 0.15 cm3 (maximum error) % error = (0.15 � 100) / 28 = � 0.5% 4. The overall apparatus error The overall apparatus error = 0.2% + 0.2% + 0.5% = � 0.9% 4.2 Comparison between experimental Mr with value of likeliest acid My experimental value is 62.37 which are theoretically very close to the value of nitric acid from the table (shown in analysis part) whose value is 63. If I add the percentage of error to my experimental result, I will get the value of 63.27. Final experimental result = experimental value + the overall apparatus error = 62.37 + 0.9 = 63.27 % difference between experimental Mr and value of likeliest value = (62 / 63.27) � 100% = 100% - 97.99% = 2.01% 4.3 Conclusion From the titration process I found the molarity of the sodium hydroxide solution and the relative formula mass of the unknown acid. With further calculations I identified the correct formula of the acid. The experiment was done without any major mistakes and complications, although there were some minor mistakes in calculations due to the apparatus used. This could be solved in another experiment by using more appropriate equipments. It will reduce the overall percentage error and minimize the mistake. ?? ?? ?? ?? The relative formula mass of an unknown acid Mateja Dujmovic Ankara, Turkey 1 ...read more.

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