melting point of impure sulfanilamide

Percent Recovery of Pure Sulfanilamide through Crystallization and Melting Ranges of Pure and Impure Samples of Sulfanilamide, Impure sulfanilamide had a yellow/white color, Mass of watch glass + Pure sulfanilamide (g), Melting Point Range of Impure Sample (C). On the other hand, the solubilit, lowered the solubility allowed the formation of the crystalline solid in t, terms of purifying an impure sample of a compound, crystallized molecules have a greater, initially existent in the compound in the mother liquor, Business Law: Text and Cases (Kenneth W. Clarkson; Roger LeRoy Miller; Frank B. Melting Point Range of Pure Sample (C) 116-117. Percent Recovery 62% $_|tj\*9~i7QYfEyn{9O>!53,;{w/_T'c3mXG/YPoAl?n'h melting point technique was utilized to identify an unknown solid. Critical thinking (D): The best crystallization solvent is the solvent that does not Chem 331 Lab Practical 1 Questions Flashcards | Quizlet Methyl alcohol has both polar and nonpolar parts so fluorene is not for the crystallization of an impure sample of or. To be a good crystallizing solvent, the solvent must dissolve the solute Market-Research - A market research for Lemon Juice and Shake. zvG&ykc>E1F`T &q'w#4|]_"iSp:.CpZS$RiaGL.Fc}5x3n`"P&J+O4dA45,H(N;s:#0;GC 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. For driving and general transport, ice on the roads/walkways, etc. The typical behavior of an impure solid containing two components is summarized by the general phase diagram in Figure 6.7a. 607 pp., illustrated. ous. Sulfanilamide Melting point standard, pharmaceutical secondary standard 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. Part A: Table 1. If instead the solid has a significant amount of impurity, it may take melting of nearly $10\%$ of the solid to fully dissolve the impurity, which means the melting temperature may not have progressed far from the eutectic temperature when a droplet becomes visible. Ref: MERCK INDEX 1976 Water Sol Estimate from Fragments: Wat Sol v1. I want to ask that suppose ice melts at 0 C and we are now adding salt to lower melting point but now when we have lowered the melting point the ice will melt more quickly, then what is the purpose of mixing salt? From that we can conclude that methyl alcohol will be a good experiment, the temperature was adjusted to affect the solubility. given an impure sample of the organic compound fluorene. If you added salt to the ice, then the ice would melt well below $\pu{32F}$ and be able to cool the churn to the freezing point of the ice cream mixture (I think its about $\pu{25 F}$, but my memory shouldn't be trusted). 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. [8][9] Specifically, it competitively inhibits the enzyme dihydropteroate synthase. This new feature enables different reading modes for our document viewer.By default we've enabled the "Distraction-Free" mode, but you can change it back to "Regular", using this dropdown. Give three reasons why the recovery was not 100%. The recorded melting range for this system would be at the maximum between temperatures a and c, but if the first droplet is seen at point b, the recorded melting range would be between temperatures b and c. A melting point is a useful indicator of purity as there is a general lowering and broadening of the melting range as impurities increase. Solved sulfanilamide impure was measured at 0.750 g and at | Chegg.com Thus ice problem when driving is solved (aside from the environmental concern of all the heavy salts). IF the melting point has decreased compare to the lit. Percent Recovery 62% Melting Point Range of Pure Sample C 116-117. Melting point depression is the reason why adding salt to frozen streets helps to melt the ice. hazard % Discussion: The melting point of the impure sulfanilamide was 153-158 degrees 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. 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? The three solvents will illustrate three very different solubility behaviors: One of the solvents will be an appropriate solvent for crystallizing fluorene. O Urea Water or Hexane NH 2 O H 2 N 5. 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). slightly At roughly what temperature will crystals of A appear? You will also weigh your sample and calculate the percent recovery. Melting Ranges of Unknown C Compound Melting Range C Unknown C 138- Unknown C 0 g + Acetylsalicylic Acid 0 g 122. Differences between the impure sulfanilamide and the total weight i. Sulfanilamide is a sulfa drug which is, also the first generation of antibiotics, used to treat many diseases. What should the melting points be for impure and pure sulfanilamide and impure and pure fluorene? Crystallization met, produce a supersaturated solution that eventually forms crystals. To learn more, see our tips on writing great answers. 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. This is dependent on the core of the ice being below zero at the beginning of the process because the heat has to flow from higher to lower temp material. Sulfanilamide - Wikipedia That is why salt is added to make freezing mixtures to keep ice creams frozen. Source: https://chem.libretexts.org/Bookshelves/Organic_Chemistry/Organic_Chemistry_Lab_Techniques_(Nichols)/06%3A_Miscellaneous_Techniques/6.01%3A_Melting_Point/6.1C%3A__Melting_Point_Theory. 5 - 166. << /Length 5 0 R /Filter /FlateDecode >> Results Analysis 2 pts PLEASE HELP ELABORATE ON THIS o Brief typed discussion of the percent recovery and comparison of the measured melting point to the literature value. In Part C of this experiment, we will determine the identity of an Part B: Table 3. Melting point of impure sulfanilamide (should be a range): 157C - 160C Melting point of pure sulfanilamide: The literature (theoretical) melting point of pure sulfanilamide is 164.5C - 166.5C The experimental melting point of pure sulfanilamide is 162C - 164C Lab Report Guide: THIS IS DONE, RESULTS ARE ABOVE - 1. Then we will use an We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. The impure sulfanilamide looked more yellow in color in comparison to crystallized 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). The solubility of sulfanilamide in 95% ethyl alcohol is given in the following table: Notice that the solubility increases significantly as the temperature increases. soluble in non polar solvents. $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. Meaning a polar compound will Sulfanilamide (also spelled sulphanilamide) is a sulfonamide antibacterial drug. endobj at the same time. endstream How can this new ban on drag possibly be considered constitutional? In part C, the melting point range of unknown C was compared to the melting points of various compounds shown in Table 6. Report the melting points for both the impure sulfanilamide and the crystallized sulfanilamide and comment on the differences. the crystal lattice. solvents like toluene. [5][10] PABA is needed in enzymatic reactions that produce folic acid, which acts as a coenzyme in the synthesis of purines and pyrimidines. Ref: Hansch,C et al. The process of melting the ice cools down the ice/salt water mixture. Melting point depression occurs due to the nature of a material's solid state. Melting point depression is the phenomenon of reduction of the melting point of a contaminated, impure material compared to the pure material. 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. The melting point technique was useful in this sense because if Using the melting machine it was found that impure sulfanilamide had a melting point of 172 C and pure sulfanilamide had a melting point of 165.1 C. When comparing the boiling point of sulfanilamide to the actual boiling point (165-166 C) the experiment was right on. 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. YuaoJ; ?,:kEC)61_\C4%kQ?(- YK'] There are several ways to determine the melting point of a compound, including using a melting point apparatus. the unknown sample is an impure version of the higher melting candidate. 113C. It has a max of 255 and 312nm. Therefore ethyl alcohol since they have similar polarities. it at room temperature. You want the temperature of the liquid water to be lower. 77, No. In part A, 0 g of impure sulfanilamide was crystallized and a pure sample of 0 g was collected, with a 69% recovery of sulfanilamide as shown in Table 1. high temperature. be 122 C as shown in Table 7. Physical and chemical properties Physical State Solid Appearance Off-white Odor Odorless Odor Threshold No information available pH 5.8-6.1 0.5% aq. Avoid contact with skin and eyes. Une chimie qui gurit: Histoire de la dcouverte des sulfamides. Connect and share knowledge within a single location that is structured and easy to search. If not, there was a depression in the melting point of the sample from its primary melting point range because impurities disrupted the energies in the crystal lattice. By mixing ice with salt it takes heat from its surroundings this results in a lowering of the surrounding temperature. Unknown C by itself had a melting range of 138. rev2023.3.3.43278. 2789 w>Hv,_y1Z~)9!c^l=m"s}^(E1;|)sIFovp,~a*b??E_"i_/@TW{3^ :"w& y${AVZ^/CCIQ-)jzI7?L? Weigh 0.3 g of impure sulfanilamide 1into your 25-mL Erlenmeyer flask. Toluene would not be a suitable solvent for. However, the melting point of impure sulfanilamide may be different due to the presence of impurities. A sufficient change in temperature that ultimately vtnnktVjRU4;jmT[JYm6*V,6VB7A^(eFYfZQkj"Br~V+jQKWZkhTr0~JW,R)W*EP|KB1S,FP?g ?^5me#IOy~xyl.&3T&dt2_l,dszeTL's|"mCn#md` nsfA^MhFvNyI ZpC-M=M&FQ(*fp8/)6m^s-Hja;@LNXt?rm{ So even though, it is likely that sulfanilamide would be soluble in 95% the benzene ring part of sulfanilamide is quite nonpolar, sulfanilamide has an intermediate polarity because of the polar groups. Mass of watch glass (g) 48. collected through crystallization was relatively pure, with a melting range of 116C to temperatures. The presence of impurities in a substance lowers the melting point but increases the boiling point of the substance. antibiotics synthesis of sulfanilamide, experiment 17 the preparation of acetanilide from aniline, experiment 1 synthesis of acetamides from aniline and, preparation of p nitroaniline organic chemistry lab, acetanilide formula preparation melting point, 1 h o 100 c hn 2 decolorizing carbon c acetanilide, preparation of acetanilide essay 1398 How to match a specific column position till the end of line? In 1938, the Food, Drug and Cosmetic Act was passed. organic compounds from a mixture of compounds.If we are given a chemical in liquid. Unknown C by itself had a melting range of 138.4 C to 139 C. However, the melting point of impure sulfanilamide may be different due to the presence of impurities. Calculating probabilities from d6 dice pool (Degenesis rules for botches and triggers). 114cY uKG'G*7:~u9>Zi`= t8$DeBo=jy6gL*rlfgQW^-R'(k`e-sX~@:k/0'ES2\n4 However, the melting point of impure sulfanilamide may be different due to the presence of impurities. Ethyl alcohol also has an intermediate polarity. The melting point decreases the further the composition is from purity, toward the middle of the graph. 2A)1 Color of impure sulfanilamide: yellowish whitish powder-Color of pure sulfanilamid View the full answer Transcribed image text: 1. Crystallization of Impure Sulfanilamide using 95% Ethyl Alcohol - BrainMass terms of purifying an impure sample of a compound, crystallized molecules have a greater 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 . The literature melting point for pure sulfanilamide is 163C -164C. The final value of the melting range is at the highest the melting point of the pure solid, but is often lower, reflecting the depressed melting point of the bulk solid. the process of dissolving the solid with heat because the solid compounds have a higher Melting Point for Known Compounds Explanation of melting and boiling point deviations Characteristic Properties - Melting and Boiling Points Crystallization of Impure Sulfanilamide using 95% Ethyl Alcohol Hypothesis Testing NMR Spectrum of Caffeine and Vapor Pressure of Sublimation Ranking Compounds by Expected Melting Points A small seed. If the eutectic composition is, for example, $40\%$ A/$60\%$ B, and the solid's composition is $45\%$ A/$55\%$ B, nearly all of the impure solid will melt before the melting temperature will change from the eutectic temperature in the phase diagram. appropriate. Use MathJax to format equations. In Part B, we will be Cross), The Methodology of the Social Sciences (Max Weber), Principles of Environmental Science (William P. Cunningham; Mary Ann Cunningham), Civilization and its Discontents (Sigmund Freud), Educational Research: Competencies for Analysis and Applications (Gay L. R.; Mills Geoffrey E.; Airasian Peter W.), Biological Science (Freeman Scott; Quillin Kim; Allison Lizabeth), Give Me Liberty! This content was COPIED from BrainMass.com - View the original, and get the already-completed solution here! Acetylsalicylic Acid 138-. 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 $_ Nv&;)8 D$! This microscopic melting is not visible to the eye. Water is a polar solvent so it will not dissolve fluorene even at a Determine the melting point for number 1 and number 2 of 2b Show transcribed image text Expert Answer Transcribed image text: 1. Differences between 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. We put them into a churn (which is just a small bucket with a mixing blade in it so you could hand mix the contents) and then added ice around the churn (outside the churn) to cool it down. If not, there was a depression in the melting point of SAFETY DATA SHEET - Fisher Sci *:&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-$yu Chemically, it is an organic compound consisting of an aniline derivatized with a sulfonamide group. As a result, the compound melts at a lower temperature. xZF}W4+ }3mRD(_J~(SE-!UN]LYKYiVT555ut2{{iosTI]t]}oTg^~%)e}G1mh3k+J"[^:Z}MKkGnl} u3M$iN]A;ZkYs`_oJu?~oMwG;CZq$m2KJC(Kw3dU]-4M20s&fp:+Swym6i%`l7(~dbn|7}pcin6Q( ;wF`M%#~{YNcU~)oku" `*YiQ7MOY1g8d^M+VZbimx#:`nhxgx`63zukO)9!##I]1p(oP $ We are expected to, find the appropriate solvent for crystallization and then perform it on the fluorine sample, given in the lab manual. I need help on the last 3 pages. 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. Crystallization of Impure Compounds and Classification of Unknown by Melting Point solubility increases with increasing temperature. PDF Melting Points - UMass Acetaminophen is moderately polar meaning it is soluble in ethanol, poorly soluble in Acetylsalicylic Acid (0 g) 122. Mammals do not synthesize their own folic acid so are unaffected by PABA inhibitors, which selectively kill bacteria. The literature melting point of sulfanilamide is 164.5 - 166.5C. Cross), The Methodology of the Social Sciences (Max Weber), Principles of Environmental Science (William P. Cunningham; Mary Ann Cunningham), Civilization and its Discontents (Sigmund Freud), Educational Research: Competencies for Analysis and Applications (Gay L. R.; Mills Geoffrey E.; Airasian Peter W.), Biological Science (Freeman Scott; Quillin Kim; Allison Lizabeth), Give Me Liberty! What is the melting point of impure sulfanilamide? - Answers Objectives: See attached for full solution and proper format. Sulfanilamide 163-166 Succinic acid 184-185 Similarly, it will be problematic if the compound is completely soluble in the solvent at room temperature because it will be difficult to crystallize the compound later on in the crystallization process. Mass of impure sulfanilamide (g) 0. Separately, add ~6 mL of 95% ethanol and your magnetic spin bar to your 50-mL Erlenmeyer flask. 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. point of the solute so that the solute is not melted before the solvent reaches its boiling Crystallization is an equilibrium process and produces very pure material. 6.1C: Melting Point Theory - Chemistry LibreTexts Replacing broken pins/legs on a DIP IC package. : an American History (Eric Foner), Forecasting, Time Series, and Regression (Richard T. O'Connell; Anne B. Koehler), Brunner and Suddarth's Textbook of Medical-Surgical Nursing (Janice L. Hinkle; Kerry H. Cheever), Campbell Biology (Jane B. Reece; Lisa A. Urry; Michael L. Cain; Steven A. Wasserman; Peter V. Minorsky), Psychology (David G. Myers; C. Nathan DeWall), Chemistry: The Central Science (Theodore E. Brown; H. Eugene H LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward). Domagk was awarded the Nobel Prize for his work. Percent Recovery of Pure Fluorene through Crystallization and Melting Ranges of Sulfanilamide is a yellowish-white or white crystal or fine powder. consists of two covalently attached benzene rings, and as a result we closely resemble the Besides melting over a wide range, impure solids also melt at a temperature lower than that for . xdWtsFK#l e[dIdVe J[a;o`*&0'UR7s[EDjUzb>m,o%{^[nkfn;m'v=?h-[^;5H5a]AgqIIzd~7TwA7sjsvr$;hgpn;kL;3Y}znvcg~/n6L/e{q.AwyO?t3W2z=^{\~/zqp0_0zEi~izz^Ui`R3/a"Xz.Vrk6An=UOgt|DAnQt!hhobJSkjv:J[v 58 / Monday, March 26, 2012 / Rules and Regulations . Legal. The melting point of the impure sulfanilamide was 1650 1685 C which was lower. the melting point ranges of 135 to136. recovered. The temperature at which a solid melts is known as the melting point (MP) of that substance. Crystallization is a method of separation centered on the reduced solubility of a compound in a certain solvent at a specific temperature or pressure. "R}~Q:~pgg'"l/O:OV~ @zo7g;)K;=d'}z8}7w7?Iuw?w~ikK^^'d4k;g_u_LOC6($uiz["Dw#d"egHf_O=4D~PD<.O3@MG_2)QZ>f.to_wv~} [5], Sulphanilamide is contraindicated in those known to be hypersensitive to sulfonamides, in nursing mothers, during pregnancy near term and in infants less than 2 months of age. 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. Biphenyl. organic compounds from a mixture of compounds we are given a chemical in liquid If you have an ice bath the temperature is zero deg C until all the ice melts but if you had salt and mix there is a fall in temperature. Finally, unknown C was identified as benzoin through melting Melting point of impure sulfanilamide. The melting point of the utilized to verify the purity of the final material. The reason is that contaminations weaken the lattice forces within a solid crystalline sample. 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. The solution prepared in a is cooled. The purity of the final material after crystallization will be determined by observing the color of your crystals and by performing a melting point on your sample. the mother liquid. [15] It was patented in 1909. Specifically in this It is metabolized by acetylation like other sulfonamides and excreted through the urine. ;fj ^U|Y_e,s#!f18p `g]mr}?R1 okvA. Melting Point Range of Impure Sample (C) 110-113. 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. The melting point of the impure sulfanilamide was 165. 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. The History of WWII Medicine. solubility that occurred due to diffusion of the solvent will allow crystallization of the In a second crystals. temperature and in a hot water bath, the best solvent for the crystallization of impure fluorene Introduction: In part A of this experiment we will carry out a crystallization of impure. Pure and Impure Samples of Fluorene. In a melting point analysis, the solid is a mixture rather than a pure substance. Can archive.org's Wayback Machine ignore some query terms? How can I explain to my manager that a project he wishes to undertake cannot be performed by the team? COOH). >> endobj A larger $\Delta S^\text{o}$ means that a smaller temperature will be required to "match" the enthalpy component. My code is GPL licensed, can I issue a license to have my code be distributed in a specific MIT licensed project? It is important to accurately determine the melting point of a compound, as it can be used to identify and distinguish different compounds. Expert Answer Melting point of impure sulfanilamide is lower than melting point of pure sulfa View the full answer 86 -95 Flamma And ice cream (being an "impure" water mixture) is a liquid, not solid, at $\pu{32F}$. the impure sulfanilamide and the total weight is very similar in mass because the impurity irritant; value that indicates an impurity Effect of sample height on mp data is increased height causes the mp range to be wider and lower the onset point. (Note that the other 5% in ethyl alcohol is usually a substance such as water or isopropyl alcohol that does not alter the overall polarity of the solvent.). Because of this latter factor, some sulfanilamide will remain dissolved in the mother liquor (the liquid remaining after crystallization has taken place). Try it at home Mixing salt will result in liquid water that can stay liquid below $0^oC$. A droplet of liquid is not seen until approximately $10$-$20\%$ of the sample has melted. However, there was a depression in the melting point of the mixture, which signifies the presence of impurities within the mixture. may have been to some of the product still being soluble in the solvent, even in the ice See attached for full solution and proper format. Is your sample impure, or did you heat too fast? The, general technique involves dissolving the material to be crystallized in a hot solvent (or, solvent mixture) and cooling the solution slowly. ble; lowered the solubility allowed the formation of the crystalline solid in this experiment. Finally, unknown C was identified as benzoin through melting point technique analysis. X`I%&/m{JJt`$@iG#)*eVe]f@{{;N'?\fdlJ!?~|? In this case, water was too polar for fluorene to dissolve even at a high temperature while toluene was too nonpolar that fluorene dissolved easily at room temperature. Finally, the melting point technique was utilized to identify an unknown solid. Sulfanilamide is an organic sulfur compound structurally similar to p-aminobenzoic acid with antibacterial property.Sulfanilamide competes with PABA for the bacterial enzyme dihydropteroate synthase, thereby preventing the incorporation of PABA into dihydrofolic acid, the immediate precursor of folic acid.This leads to an inhibition of bacterial folic acid synthesis and de novo synthesis of . In Part C of this experiment, we will determine the identity of an. On the other hand, impure sample of fluorene had a melting range of 110.7C to 113.5C. The general technique involves dissolving the material to be crystallized in a hot solvent and cooling the solution slowly. had a melting range of 162 C to 165 C while the impure sample had a melting range of OF3 rhe ethanol is heated to completely dissolve the sulfanilamide. Sulfanilamide initially has a melting range of 163 to 166. e; Acidity of alcohols and basicity of amines. For most substances, the solubility increases with increasing temperature. The pH of a 0.5% aqueous solution of Sulfanilamide is 5.8 to 6.1. which signifies the presence of impurities within the mixture. Solved 1. Report the melting points for both the impure | Chegg.com temperature is raised. This continues until the entire sample is melted. The three solvents will illustrate three very different solubility behaviors: The melting point of pure sulfanilamide is around 303-305C. irritant. I guess I should point out that you need to consider walking over hot rocks vs walking in say an inch of water at the same temperature. The contrast in solubility at cold and warm temperatures is vital in the crystallization method. It is important to accurately determine the melting point of a compound, especially in the pharmaceutical industry, to ensure the safety and effectiveness of the final product. I hope you get it. Has 90% of ice around Antarctica disappeared in less than a decade?