The temperature at which a solid melts is known as the melting point mp of that substance. The melting point of the aspirin was found to be 110115. This book contains eight freestanding activities that can be used singly or as a coherent package in a wide range of teaching and learning situations for both. The problem with getting a value for the melting point of an organic substance is the purity of the material. Specific inflammatory conditions which aspirin is used to treat include kawasaki disease, pericarditis, and rheumatic fever. The melting point of a compound is the temperature at which the solid phase and. Bulletin of the chemical society of japan 1950, 23 1, 2325. The melting point is a physical property of a solid and can be used to help identify a substance. It also helps to know the source of the information some sources are more rigorously researched than others. This sample had a median melting point temperature of 129oc. If the expected melting point of the compound is not known, heat the sample at a medium rate the entire time and determine an approximate melting point. Acetylsalicylic acid is weakly acidic substance with a melting point 6c. Suggest why a pure sample of aspirin may sometimes appear to.
Also, the literature value is obtained under strict lab conditions. The melting point temperature ranges were 126oc2oc and 129oc4oc for the crude and recrystallized aspirin samples, respectively. Range of the melting point indicate the purity of the compound. One of the compounds used in the synthesis of aspirin is salicylic acid, which is itself a pain reliever that was known to many ancient cultures, including the native americans who extracted it from willow tree bark. In practice, a solid usually melts over a range of temperatures rather than at one specific temperature. Record the first temperature of the melting range with the. Before the melting point was determined if one crystal sample contain. The aspirin crystals should be firmly packed, and fill the capillary tube to a depth of no more than 12 mm. Aspirin, the ubiquitous pain reliever, goes by the chemical name acetylsalicylic acid. Sample name material weight melting point range actual temperature of melting impure acetanilide mixture 1. What does it mean when a sample has a higher melting point. Stepbystep procedures for melting point determination.
Pdf crystallization and morphological characteristics of acetyl. The recrystallization and dissolution of acetylsalicylic acid ubc. Aspirin is also used longterm to help prevent further heart attacks, ischaemic. Aspirin originally was derived by boiling the bark of the white willow tree. Your experiment may have some unisolated variables, such as calibration of temperature measurement equipment and also you will have errors. Then, read through sections 1 and 2 of chapter 3 describing the prelab writing format with examples.
The essays introduction, body paragraphs and the conclusion are provided below. Therefore, be forewarned that the prelab is quite extensive and because its your first one, will probably take about two hours to do. To check the purity of the aspirin the student determined its melting point. Sypnopsis in this experiment, acetylsalicylic acid was synthesized from the acidification of salicylic acid and acetic anhydride. State two observations during this melting point determination, that would indicate that the sample is not pure. A melting point capillary tube with 12cm depth of fine crystals was loaded. Before the melting point was determined if one crystal sample contains methanol due to incomplete solvent removal, and the other crystal sample contains water by absorbing moisture in the air what effect could these have on the observed melting points from the two samples. Aspirin synthesis lab report by eddie zhang on prezi. Results at the end of the experiment, the result gotten should be a result of 40 60 % yield and a melting point that is around the theoretical melting point of aspirin. Caffeine is a trimethylxanthine in which the three methyl groups are located at positions 1, 3, and 7. Determine accurate melting point ranges for a wide variety of organic.
Answer to a pure aspirin has a melting point of 56c. Glass capillaries are used to determine the mixed melting point. Aspirin british pharmacopoeia bp reference standard synonym. Fusion melting point data from nist standard reference database 69. The crc handbook of chemistry and physics hbcp contains over 700 tables in over 450 documents which may be divided into several pages, all categorised into 17 major subject areas. The melting point range of pure aspirin is 8140 c and the melting point range of the salicylic acid starting material is 158161 c. Melting points university of massachusetts amherst. Acetylsalicylic acid, european pharmacopoeia ep reference standard. Now do titration of the samples stored after each recrystallisation. If impurities are present in your crude sample, the melting point range for your product will be lower than the range of pure aspirin.
The preparation of aspirin, the recrystallisation of aspirin and the melting point determination of aspirin. Take some of aspirin for each sample and leave some in the test tube for testing the melting point. Dont heat too fast aspirin is used to relieve pain, reduce inflammation, and lower fever. Also, your melting point range may be greater than 2 degrees. Learn vocabulary, terms, and more with flashcards, games, and other study tools. You are provided with a small sample of pure aspirin in a melting point tube. Start studying chemistry isa 2 past papers learn vocabulary, terms, and more with flashcards, games, and other study tools. Using recrystallisation improve the purity of aspirin biology essay. In this experiment, you will measure the melting point of your synthesized asa product, salicylic acid, a crushed aspirin tablet, and pure asa from a manufacturer. Introduction in this laboratory you will identify an unknown compound by using mixture melting points. The median melting point temperature of this sample was 1.
Due to its wide range, and lower value than that of the theoretical melting point of 6c, it was assessed that the prepared aspirin was impure. It is particularly used for organic compounds, where a sample with a known identity and melting point is mixed with an unknown purified sample to determine the melting point. Aspirin british pharmacopoeia bp reference standard 2. You can also buy a copy of this book via the royal society of chemistry online shop for. The melting point of the experimental aspirin sample will be identified using a melting point apparatus which will act as the indicator to justify the purity of the sample. Predict a melting point if you combined and mixed 10 mg each of the three reference samples. Preparation of aspirin and determination of the melting point.
This essay sample essay on synthesis of aspirin offers an extensive list of facts and arguments related to it. Nist chemistry webbook the national institute of standards and technology nist uses its best efforts to deliver a high quality copy of the database and to verify that the data contained therein have been selected on the basis of sound scientific judgment. The physical properties of a substance can be used to establish its purity. There are a variety of methods by which a samples melting point can be measured, with the. Aspirin given shortly after a heart attack decreases the risk of death. A pure sample of a substance will melt at a sharply defined temperature, an impure sample will show a larger range.
To use the concept of melting points for identification and characterization of organic compounds. This book contains eight freestanding activities that can be used singly or as a coherent package in a wide range of teaching and learning situations for both academic and vocational courses. Depending on the impurity material, it could lower or higher the melting point, in your case it is making it higher. Different substances tend to have different melting and boiling points, and any pure substance will have a specific melting and boiling point. You will mix iron iii nitrate with salicylic acid in your aspirin sample to complex the salicylic acid, which is a bluishpurple colour. Preparation and recrystallisation of aspirin 1796 words 8 pages. Salicylic acid is extremely bitter tasting, and frequent use can cause severe stomach. Organic chemistry students determine the melting point of samples. Properly fill and use a capillary melting point tube. In the next activity you measure the melting point of your sample before and. First, read through the introduction and all the experimental sections given in this chapter.
A purine alkaloid that occurs naturally in tea and coffee. It has a role as a central nervous system stimulant, a ryanodine receptor modulator, an ec 3. Although the salicin in willow bark has analgesic properties, purified salicylic acid was bitter and irritating when taken orally. The melting point of the experimental aspirin sample will be identified using a melting point. Determine the percentage of aspirin acetylsalicylic.
Insert the capillary tube containing the sample into the melting point apparatus. Melting point determination identity and purity of solid organic compounds objectives to introduce the technique of melting point determination. The search on this page works by searching the content. Experimental synthesis of aspirin and melting point purity.
Find, read and cite all the research you need on researchgate. Start studying chemistry empa ppq sections b and c. Hence, the depression of the melting point of individual crystals is related to. Aspirin, also known as acetylsalicylic acid asa, is a medication used to reduce pain, fever, or inflammation. Determining the relative percent yield and attained purities of different synthesis processes is vital to the viability of an affordable commercial product for the aspirin market. If the aspirin crystals were not completely dried before. Aspirin melting point essay medicine and health articles. On the anomalous melting point and the decomposition of acetylsalicylic acid. Mixed melting point is a technique used to identify chemical compounds. Record the temperature where the melting point is first observed and when it becomes a liquid completely.
In lab today, we measured the actual yield and melting point of aspirin that we had made in lab last week. Repeat the process with a fresh sample after allowing the apparatus to cool and use the recommendations in prompt 4 to perform a more careful assessment of the melting point. These properties include the melting point and boiling point. Describe briefly how you would determine an accurate value for the melting point of this aspirin. The experimental melting point range of aspirin was determined to be 122 2c. Preparation and recrystallisation of aspirin contents page synopsis iii 1 introduction 1 1. A compound that contains impurities will tend to melt over a range of temperatures and at temperatures lower than the fixed mp for the pure compound. Since the melting point of pure aspirin is 8140, this means that our aspirin was. Aspirin rsc education the royal society of chemistry. Reduce the sample to a fine powder by using mortar and pestle.