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Compound Melting Range (C) Benzyl alcohol is not the right choice for the solvent since it's boiling point is 205oC, Biphenyl is very similar in structure to benzene and has very similar polarities. In other words if you add salt to ice that is homogeneously right at the freezing point you won't get liquid water below zero because there is no where for the heat to flow. Mass of impure fluorene (g) 0. There's no question that your feet would have more contact with the water than the solid rocks, so your feet would be more damaged by the water (water at $180$ or $\pu{200 F}$ WILL burn you). The literature melting point for pure sulfanilamide is 163C -164C. the impure sulfanilamide and the total weight is very similar in mass because the impurity affinity for molecules of its own kind than for the impurities, they leave behind the impurities With prior knowledge of the fact that like dissolves like. Introduction: In part A of this experiment we will carry out a crystallization of impure. This question can be answered by referring to the guidelines for predicting polarity and solubility behavior (see Lab #3, Solubility). On May 18, 1909, Deutsches Reich Patentschrift number 226,239 for sulfanilamide was awarded to Heinrich Hrlein of the Bayer corporation. I hope you get it. The, general technique involves dissolving the material to be crystallized in a hot solvent (or, solvent mixture) and cooling the solution slowly. 166 C) to be different if the 5% impurity were trans-cinnamic acid (MP 133 C) instead of fluorenone? thermometers available in the lab that may not have been set the same way as the Some of the deductions in the percentage of recovery were due to the impurities being left behind in the mother liquor and others were due to the use of too much solvent in the process of dissolving the solid with heat because the solid compounds have a higher affinity for the solvent at a higher temperature. Melting Point Range of Impure Sample (C) 110-113. The pure sample had a melting range of 162.9 C to 165.8 C while the impure sample had a melting range of 160.3 C to 163.2 C as shown in Table 1. Benzoic acid C 6 H 5 COOH organic compounds from a mixture of compounds.If we are given a chemical in liquid. Part C: Table 6. By comparing the solubility of impure fluorene in the 3 solvents in room temperature and in a hot water bath, the best solvent for the crystallization of impure fluorene was identified as methanol. One of the solvents will be an appropriate solvent for crystallizing fluorene. crystallization solvent for fluorene, impure fluorene is dissolved in methyl alcohol at its endstream It has a density of 1.08 g/cm 3 and a melting point of 164.5-166.5 C. Impurities can be introduced into the compound during its synthesis or during its handling and storage. Mass of watch glass (g) 48. collected through crystallization was relatively pure, with a melting range of 116C to irritant, Diethyl ether (C 2 H 5 ) 2 O Business Law: Text and Cases (Kenneth W. Clarkson; Roger LeRoy Miller; Frank B. For both cases, the change in melting point has to do with homogeneous mixing in the liquid state, though, according to Lisa Nichols: An impure solid is typically heterogeneous on the microscopic level, with pure regions of each component distributed through the bulk solid much like granite. The reason is that contaminations weaken the lattice forces within a solid crystalline sample. This creates strong intermolecular forces, which give the compound a high melting point. Create three research questions that would be appropriate for a historical analysis essay, keeping in mind the characteristics of a critical r, Carbon Cycle Simulation and Exploration Virtual Gizmos - 3208158, 1.1 Functions and Continuity full solutions. Table 4. Results 3 pts o Results sheet neatly filled out with data o Proper significant figures o Legible calculation of percent recovery - 2. . << /Type /Page /Parent 3 0 R /Resources 6 0 R /Contents 4 0 R /MediaBox [0 0 612 792] 10 0 obj for the crystallization of an impure sample of organic compound, fluorene. crystal is formed initially, and it then grows layer by layer in a reversible manner. The melting point of pure sulfanilamide is around 303-305C. Enter salt. Of that sample, 0.1 grams will be saved for a melting point determination. The preliminary melting of compound A in Figure 6.7a forms tiny pools of liquid that begin to dissolve compound B from the bulk solid. Which would burn you faster? Impurities can be introduced into the compound during its synthesis or during its handling and storage. It has a density of 1.08 g/cm3 and a melting point of 164.5-166.5C. ;fj ^U|Y_e,s#!f18p `g]mr}?R1 okvA. C to 139 C. When an impure solid is warmed, microscopic melting first occurs in a pure region by the component with the lower melting point (compound A in Figure 6.7a). To use this instrument, a small amount of the compound is placed in a capillary tube, which is then inserted into the apparatus. Table 4. 3, acetaminophen C 8 H 9 NO 2 Sulfanilamide 165-167 2-Aminophenol 174 4-Toluic acid 180 . Some of the deductions in the percentage of recovery were due to the impurities { "6.1A:_Overview_of_Melting_Point" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1B:_Uses_of_Melting_Points" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1C:__Melting_Point_Theory" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1D:__Step-by-Step_Procedures_for_Melting_Point_Determination" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.1E:_Mixed_Melting_Points" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, { "6.01:_Melting_Point" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.02:_Boiling_Point" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.03:_Sublimation" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()", "6.04:_Chemical_Tests" : "property get [Map MindTouch.Deki.Logic.ExtensionProcessorQueryProvider+<>c__DisplayClass228_0.b__1]()" }, [ "article:topic", "eutectic point", "eutectics", "freezing point depression", "authorname:nicholsl", "eutectic composition", "showtoc:no", "license:ccbyncnd", "licenseversion:40", "source@https://organiclabtechniques.weebly.com/" ], https://chem.libretexts.org/@app/auth/3/login?returnto=https%3A%2F%2Fchem.libretexts.org%2FBookshelves%2FOrganic_Chemistry%2FOrganic_Chemistry_Lab_Techniques_(Nichols)%2F06%253A_Miscellaneous_Techniques%2F6.01%253A_Melting_Point%2F6.1C%253A__Melting_Point_Theory, \( \newcommand{\vecs}[1]{\overset { \scriptstyle \rightharpoonup} {\mathbf{#1}}}\) \( \newcommand{\vecd}[1]{\overset{-\!-\!\rightharpoonup}{\vphantom{a}\smash{#1}}} \)\(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\) \(\newcommand{\id}{\mathrm{id}}\) \( \newcommand{\Span}{\mathrm{span}}\) \( \newcommand{\kernel}{\mathrm{null}\,}\) \( \newcommand{\range}{\mathrm{range}\,}\) \( \newcommand{\RealPart}{\mathrm{Re}}\) \( \newcommand{\ImaginaryPart}{\mathrm{Im}}\) \( \newcommand{\Argument}{\mathrm{Arg}}\) \( \newcommand{\norm}[1]{\| #1 \|}\) \( \newcommand{\inner}[2]{\langle #1, #2 \rangle}\) \( \newcommand{\Span}{\mathrm{span}}\)\(\newcommand{\AA}{\unicode[.8,0]{x212B}}\), 6.1D: Step-by-Step Procedures for Melting Point Determination, Melting Point Depression (Lowering the M. P.), source@https://organiclabtechniques.weebly.com/, status page at https://status.libretexts.org. And then you mixed and mixed and mixed and mixed. This is true for several reasons: experimental loss, the original sample is not 100% sulfanilamide, and some sulfanilamide is soluble in the solvent even at 0 C. A very pure sample will have a narrow melting point range that will be close to the literature value (supposedly determined on a very pure sample). It has a max of 255 and 312 nm. Some sources of sample loss of the sulfanilamide Crystallization of Impure Compounds and Classification of Unknown by Melting Point endobj solvents like toluene. Variations in Psychological Traits (PSCH 001), Expanding Family and Community (Nurs 306), American Politics and US Constitution (C963), Health Assessment Of Individuals Across The Lifespan (NUR 3065L), Leadership and Management in Nursing (NUR 4773), Creating and Managing Engaging Learning Environments (ELM-250), Professional Application in Service Learning I (LDR-461), Advanced Anatomy & Physiology for Health Professions (NUR 4904), Principles Of Environmental Science (ENV 100), Operating Systems 2 (proctored course) (CS 3307), Comparative Programming Languages (CS 4402), Business Core Capstone: An Integrated Application (D083), Lesson 6 Plate Tectonics Geology's Unifying Theory Part 2. Econ 1 - Chapter 1 Questions and Answers. The higher the concentration of the impurities, the more anomalous the melting point.. >> OF3 rhe ethanol is heated to completely dissolve the sulfanilamide. Sulfanilamide is a white, crystalline compound that is used as an antibiotic and as a raw material in the production of other pharmaceuticals. The melting point is recorded as the temperature at which the compound transitions from a solid to a liquid. Acetaminophen is moderately polar meaning it is soluble in ethanol, poorly soluble in e; Results and Discussion In terms of purifying an impure sample of a compound, crystallized molecules have a greater affinity for molecules of its own kind than for the impurities, they leave behind the impurities initially existent in the compound in the mother liquor, to ultimately yield relatively pure crystals. 4 0 obj Has 90% of ice around Antarctica disappeared in less than a decade? In the old fashioned process, we used buttermilk sugar and a bit of vanilla. We should This page titled 6.1C: Melting Point Theory is shared under a CC BY-NC-ND 4.0 license and was authored, remixed, and/or curated by Lisa Nichols via source content that was edited to the style and standards of the LibreTexts platform; a detailed edit history is available upon request. health Z6i ;>H@ rwIlSk`rOcHRs+idf4[i3Dqaz 9s)/M~"cN\!7xYIhKy7360di+4f[>2e(nZ7I=OIaP:t+b,R A~TUY u|S={~iUf50R!IO9WtpxDuUu=$#>mq^l-,.BtfNyOB9oKn^"M,++*xx~\6m2xn#x:0JhOE\ZyzrsYtlE;b^T}pB3Pxs5~PH1yeF./3O/iBRvD D0z@.^wtpJZ8$2x18 $_ Nv&;)8 D$! Whether a system is in fact pure, or sharply melting because it is at the eutectic composition, can be proven by performing a mixed melting point. Sulfanilamide initially has a melting range of 163 to 166. 5 0 obj Some systems do not have any eutectic points and some have multiple eutectic points. Therefore, by process of elimination, unknown C was identified as benzoin. Unknown C by itself had a melting range of 138.4 C to 139 C. Now the temperature at which the water freezes is much lower than the surrounding temperature so the water will still exist as a liquid form even when the temperature is lower than the normal freezing point. Purpose: in this experiment we will get introduced to the technique of crystallization. sul- fanilamide in 95% ethyl alcohol as the solvent. The melting point technique was useful in this sense because if elimination, unknown C was identified as benzoin. In part A, 0.746 g of impure sulfanilamide was crystallized and a pure sample of 0.519 g was collected, with a 69.57% recovery of sulfanilamide as shown in Table 1. benzene polarity know that like dissolves like, so biphenyl will be highly soluble in % Finally, unknown C was identified as benzoin through melting point technique analysis. Sulfanilamide (also spelled sulphanilamide) is a sulfonamide antibacterial drug. The melting point of ice decreases from 0 C to -22 C on mixing salt in it in proper proportion. endobj What should the melting points be for impure and pure sulfanilamide and impure and pure fluorene? It is instructive to look at the structure of sulfanilamide and ask whether or not 95% ethyl alcohol should be a reasonable solvent for crystallizing this substance. 151 168-172 Practically Toluene is a nonpolar solvent so fluorene will be soluble in in this experiment we will get introduced to the technique of crystallization, In part A of this experiment we will carry out a crystallization of impure, crystallization will be used to purify the desired compound and isolate solid, Variations in Psychological Traits (PSCH 001), Expanding Family and Community (Nurs 306), American Politics and US Constitution (C963), Health Assessment Of Individuals Across The Lifespan (NUR 3065L), Leadership and Management in Nursing (NUR 4773), Creating and Managing Engaging Learning Environments (ELM-250), Professional Application in Service Learning I (LDR-461), Advanced Anatomy & Physiology for Health Professions (NUR 4904), Principles Of Environmental Science (ENV 100), Operating Systems 2 (proctored course) (CS 3307), Comparative Programming Languages (CS 4402), Business Core Capstone: An Integrated Application (D083), Lesson 6 Plate Tectonics Geology's Unifying Theory Part 2. Then we will use an ncdu: What's going on with this second size column? D! In this case pure water at this temperature will be in the solid phase and exist as ice because the surrounding temperature is lower than the melting/freezing point. recovered. water bath. and acetylsalicylic acid. However, the presence of impurities weakens the lattice, making it less stable. The melting point of a sample is usually expressed as two numbers called the melting point range, such as 112 - 114C. While the pure sample lied within the primary The melting point of the mixture of the two compounds came out to If a trace amount of an impure compound, whose melting point is 80-82 degrees Celsius, is mixed in with the first compound, what happens to the melting point of the pure compound? There are several ways to determine the melting point of a compound, including using a melting point apparatus. Methyl alcohol has both polar and nonpolar parts so fluorene is not Some sources of sample loss of the sulfanilamide may have been . [20], Sulfanilamide is a yellowish-white or white crystal or fine powder. Crystallization is a method of separation centered on the reduced solubility of a compound in And ice cream (being an "impure" water mixture) is a liquid, not solid, at $\pu{32F}$. From that we can conclude that methyl alcohol will be a good 2 0 obj comparable melting points when each is pure, provides a useful laboratory technique. The paragraph is therefore a tad confusing. acid, 138 C to 140C. So, the salt and ice form a salt water mixture which can be well below $\pu{32F}$, and so can cool to below $\pu{32F}$. slightly In part B, by comparing the solubility of impure fluorene in the 3 solvents in room temperature and in a hot water bath, the best solvent for the crystallization of impure fluorene was identified as methanol, as shown in Table 3, because fluorene was only partially soluble in methanol in room temperature and completely soluble in methanol at a higher temperature. For example: Melting Range 6 . Since the impurities are usually present in much smaller amounts than the compound being crystallized, most of the impurities will remain dissolved in the solvent even when it is cooled. isolated should have been a very small amount, as not much impurity should be soluble in 163-164 C. >> There are several polar bonds in sulfanilamide, the NH and the SO bonds. Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. The melting point of the mixture of the two compounds came out to be 122.4 C as shown in Table 7. Skin: Wear appropriate protective gloves to prevent skin exposure. Market-Research - A market research for Lemon Juice and Shake. Crystallization is an equilibrium process and produces very pure material. So, salt is added to the cooling mixture and (supposedly) not to the recipe's ingredients. water, crystallisable in ethyl alcohol. - Practice the crystallization technique. As the ice melted, the water it created was at $\pu{32F}$ and even though the ice was colder (a commercial freezer is often about $\pu{15F}$ (but a home freezer is warmer)) the water kept the churn at around (usually above) $\pu{32F}$ ($\pu{0C}$). 74 -116. seeing if the mp width is less than 2.0 which shows purity, but any larger than that it's impure. Une chimie qui gurit: Histoire de la dcouverte des sulfamides. << I have also typed in red where I need help. The melting point is an important physical property that can be used to determine the purity and identity of a compound. Urea is highly polar, soluble in water, poorly soluble in hexane and crystallisable in state, it will be converted into a solid crystalline state. So, this wouldn't work. May cause methemoglobinemia, cyanosis, convulsions, and death. The melting point technique was useful in this sense because if the pure sample extracted from crystallization was pure, the melting point of the sample lied within its primary melting point range. Therefore, 95% ethyl alcohol is an excellent solvent for crystallizing sulfanilamide. which is higher than the melting point of the solute fluorenol (153-154 oC). Biphenyl. Effect of impurities on melting point. Making statements based on opinion; back them up with references or personal experience. The identity of unknown C was narrowed down to a The LibreTexts libraries arePowered by NICE CXone Expertand are supported by the Department of Education Open Textbook Pilot Project, the UC Davis Office of the Provost, the UC Davis Library, the California State University Affordable Learning Solutions Program, and Merlot. For the ice cream making process, we start with pure ice and have the impurity in the liquid. The purified substance can then be separated from the solvent and impurities by filtration. Given Melting Ranges of Known Compounds, Compound Melting Range (C) The pH of a 0.5% aqueous solution of Sulfanilamide is 5.8 to 6.1. Determine the melting point of the pure sulfanilamide and the original impure material. What Is the Difference Between 'Man' And 'Son of Man' in Num 23:19? One interesting effect of this process is that sea water freezes at a lower temperature than pure water. Benzoic acid is an aromatic carboxylic acid (Fig) which forms a colorless, crystalline solid and can be found naturally in both plants and animals and some microorganisms (del Olmo, 2017; Sandeepa, 2018). In terms of purifying an impure sample of a compound, crystallized molecules have a greater affinity for molecules of its own kind than for the impurities, they leave behind the impurities initially existent in the compound in the mother liquor, to ultimately yield relatively pure crystals. *:&E1R!f>'Q|86Kg-WmtRokv#WW( C13UpC `lbSDjY6H^'FM"q\UWn ]^V;SAO7(.S$M'"2~ 9CU20 xJe[]~ cyI+4O&2lleq %6'e"'n6 ,gquxOtL$ur :7$mPYV.!o-LIR%V9u1mH ajcGUy0> p-%zDr5#&SA4j8^"\%Qu8S$we~nsC_\w5,+fcrgi-$yu Asking for help, clarification, or responding to other answers. Part A: Table 1. Compound B will continue to dissolve in the melt, until it reaches the eutectic composition (point a in Figure 6.7b), and the system will continue to melt at this composition until the entirety of the minor component (the impurity) is dissolved. Pure water freezes at $\pu{32F}$ while sea water freezes at $\pu{28.4 F}$. is a hazard so this is a concern. hazard, 99 126 Irritant, pdf, Applying the Scientific Method - Pillbug Experiment, Leadership class , week 3 executive summary, I am doing my essay on the Ted Talk titaled How One Photo Captured a Humanitie Crisis https, School-Plan - School Plan of San Juan Integrated School, SEC-502-RS-Dispositions Self-Assessment Survey T3 (1), Techniques DE Separation ET Analyse EN Biochimi 1. It has a max of 255 and 312nm. Please see attached lab report. Melting Points. On the other hand, the solubility of a affinity for the solvent at a higher temperature. single compound by collecting the melting range of a compound consisting of unknown C The purity of the sample collected at the end of crystallization was confirmed through the measurement of the melting points of the pure and impure samples of sulfanilamide. You will also weigh your sample and calculate the percent recovery. In part C, the melting point range of unknown C was compared to the melting points Through crystallization of 0.746 g of fluorene using methanol as the solvent, 0.468 g of pure fluorene sample was extracted, with a 62.73% recovery as shown in Table 4. Give three reasons why the recovery was not 100%. endobj When an impure solid is warmed, microscopic melting first occurs in a pure region by the component with the lower melting point (compound A in Figure 6.7a). [5][10] PABA is needed in enzymatic reactions that produce folic acid, which acts as a coenzyme in the synthesis of purines and pyrimidines. The purity of the sample collected at the end of crystallization was confirmed through $_|tj\*9~i7QYfEyn{9O>!53,;{w/_T'c3mXG/YPoAl?n'h << /Length 11 0 R /Type /XObject /Subtype /Image /Width 378 /Height 484 /Interpolate Remove contaminated clothing and wash before reuse. irritant. Clothing: Wear appropriate protective clothing to prevent skin exposure. melting point technique was also utilized to determine the purity of the pure sample of both \(\Delta G^\text{o}\) is dependent on both the changes in enthalpy \(\left( \Delta H^\text{o} \right)\) and entropy \(\left( \Delta S^\text{o} \right)\) during the process (see versions of the Gibbs free energy equation in Figure 6.8b), but the changes in enthalpy are similar when melting a pure and impure solid as similar intermolecular forces are broken. [8][9] Specifically, it competitively inhibits the enzyme dihydropteroate synthase. The term "sulfanilamides" is also sometimes used to describe a family of molecules containing these functional groups. This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here! The solid will continue melting until perhaps point c in Figure 6.9a, to give a relatively narrow melting range (between points b and c). point of the solute so that the solute is not melted before the solvent reaches its boiling The system follows the melting line in Figure 6.7b either to the left or right of the eutectic temperature (depending on which side of the eutectic point is started), adjusting its melting temperature as the bulk component increases its concentration in the melt. Because of this latter factor, some sulfanilamide will remain dissolved in the mother liquor (the liquid remaining after crystallization has taken place). Although all samples start melting at the eutectic temperature, the first droplet of liquid is not seen until approximately \(10\)-\(20\%\) of the sample has microscopically melted. Sulfanilamide Revision Date 24-Dec-2021 9. Percent Recovery of Pure Fluorene through Crystallization and Melting Ranges of Pure and Impure Samples of Fluorene. Substance of higher latent heat of melting than water, similar melting point, Effect of inductive effect on boiling point,melting point and dipole movement. The breadth of an experimentally determined melting point can often be correlated to the purity of the solid. $98.50 (cloth); $69.50 (paper)", "ber Sulfamide der p-Amidobenzolsulfonsure", https://en.wikipedia.org/w/index.php?title=Sulfanilamide&oldid=1140608744, This page was last edited on 20 February 2023, at 22:08. Temperature Solubility of A in C 100 mL of water g 0 1. As a result, the compound melts at a lower temperature. I need help on the last 3 pages. On the other hand, impure sample of fluorene had a melting range of 110C to consists of two covalently attached benzene rings, and as a result we closely resemble the This is analogous to evaporation cooling down our bodies when our sweat evaporates. xdWtsFK#l e[dIdVe J[a;o`*&0'UR7s[EDjUzb>m,o%{^[nkfn;m'v=?h-[^;5H5a]AgqIIzd~7TwA7sjsvr$;hgpn;kL;3Y}znvcg~/n6L/e{q.AwyO?t3W2z=^{\~/zqp0_0zEi~izz^Ui`R3/a"Xz.Vrk6An=UOgt|DAnQt!hhobJSkjv:J[v If the melting point is within the scientifically accepted range of the material's melting temperature, then the material is presumed to be pure. The temperature is then slowly increased until the compound melts. the mother liquid. The melting point of a compound is a measure of its purity. << /ProcSet [ /PDF /Text /ImageB /ImageC /ImageI ] /ColorSpace << /Cs1 7 0 R literature value. Using Kolmogorov complexity to measure difficulty of problems? An impure sample will have a lower melting point and the range will be bigger. This increases the purity of the melt, so the melting temperature increases somewhat. Examples include: As a sulfonamide antibiotic, sulfanilamide functions by competitively inhibiting (that is, by acting as a substrate analogue) enzymatic reactions involving para-aminobenzoic acid (PABA). You will crystallize a sample of impure sulfanilamide by dissolving it in the minimum amount of boiling 95% ethyl alcohol (78 C) and then cooling the solution, first to room temperature, and then to 0 C in an ice-water bath. Why do impurities lower the melting point of an isolated substance? Market-Research - A market research for Lemon Juice and Shake. It takes longer to melt The pure sample Penatherene is highly nonpolar because of the absence of hetero atoms (N,O,S) and has The melting point of the solid from the mother liquid was 162 -165, which is not the same as the crystallized material because the solid from the mother liquid may have traces of impurity which accounts for the melting point depression. the sample from its primary melting point range because impurities disrupted the energies in