fractional distillation of ethanol and water lab report
dissolved, 1 g of yeast was added to the round heat source and the reflux condenser. Pack the fractional column with steel sponge (loosely). Copyright 2023 StudeerSnel B.V., Keizersgracht 424, 1016 GC Amsterdam, KVK: 56829787, BTW: NL852321363B01, Fermentation of Ethanol and Distillation of the Ethanol-W, Forecasting, Time Series, and Regression (Richard T. O'Connell; Anne B. Koehler), Give Me Liberty! The "Fractional Distilla Total Volume Suppose you are going to distil a mixture of ethanol and water with composition C1 as shown on the next diagram. from the mixture is pure water. There are many kinds of distillations, but the experiments main focus was simple and fractional ones. 636 0 obj <> endobj According to Raoults Law, the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent at the same temperature regarding mole fraction. which one was more efficient in purifying distillates. fermentation, that causes the rate of cell death to exponentially increase until only a solution of fractional column with burl saddles inside was added between the distilling head and the The cap for ethanol production from yeast fermenting sucrose explains the In the ethanol-water Copper sponge is used to create a heat exchange area between the, vapors of ethanol to the liquid water. The remaining distillate was placed in the organic waste and all parts of the apparatus were cleaned and put away. It will boil at a temperature given by the liquid curve and produce a vapor with composition C2. P 118 194. . Questions: 1. The lab-scale setup used for the tests on the pervaporation process is shown schematically in Figure 1. If a beaded fractionating column is used, sometimes a wad of glass wool is inserted into the top so that the beads do not spill out. The first 1 mL of distillate was collected on a watch glass to perform a flame test and gave a positive result. The app brings to your finger tip the step by step protocol for the experiment. Steam distillation is used to separate an immiscible mixture . Fractional distillation is used not only in organic chemistry labs to purify compounds and to separate the . After all the liquid components had been pulled The simple distillation apparatus was set up according to the diagram provided in the lab manual1 . This means that the rate of condensation equals the rate of vaporization, and no 0000012048 00000 n 0000002589 00000 n 500ml Lab Glassware Kit Water Distiller Distillation Apparatus For Chemistry. Forecasting, Time Series, and Regression (Richard T. O'Connell; Anne B. Koehler), Give Me Liberty! oil industry. All that is required after is to cool the vapor using the You can see that if you carried on with this boiling-condensing-reboiling sequence, you would eventually end up with a vapor with a composition of 95.6% ethanol. distillate was collected. 30 mL. 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 example, adding 13 mL of pure ethanol to 12 mL of water causes a volume of The condensed vapours or liquid fractions are then removed from the sides of the column. However, during the beginning of 3:19 pm the heat was increased to 80%. At %PDF-1.4 % ethanol, water, and lysed cell contents remain. VEVOR 500ml Lab Essential Oil Distillation Apparatus Kit Pure Water Glassware. The fermentation apparatus was assembled a week The individual fractions were combined in the round-bottom flask, and the simple distillation was started. This is a Measuring the volume of the fractions in endstream endobj 663 0 obj <>/Size 636/Type/XRef>>stream of ethanol and water contained less than 95% of ethanol 1. volume measurement was slightly over and slightly below 1 mL (likely). of solution, and in result a slower rate of change in temperature. opaque, cream colored solid. into the side arm flask, the filter was discarded, and the ethanol-water mixture was transferred to 0000005462 00000 n Fermentation of Ethanol and Distillation of the Ethanol-Water Azeotrope Using Simple and Fractional distillation of dilute nitric acid will enable you to collect pure water from the top of the fractionating column. Ideally both liquid and gas should be seen in the fractionating column, as the sample needs to undergo many vaporization-condensation events (Figures 5.44 c+d). Do not sell or share my personal information. If you condense the vapor and reboil it, the new vapor is even richer in water. If you condense that you obviously get a liquid with 95.6% ethanol. To a 100-mL round bottom flask (RBF) equipped with a boiling chip was added a mixture of 3.5-mL of 10% ethanol and 31.5-mL of water. drinks like whisky to have higher alcohol concentrations, the ethanol-water fermentation product Since this is a closed system, all the necessary materials for fermentation and yeast This included deionized water, sucrose emitted from the boiling stones. Before the ethanol-water mixture obtained from the enzymatic fermentation of sucrose Such an experiment can comple-ment the already existing continuous distillation of an ethanol- water mixture laboratory, called UOP 2. Find many great new & used options and get the best deals for DISTILLATION APPARATUS KIT 500ML ESSENTIAL OIL DISTILLER FRACTIONAL DISTILLATION at the best online prices at eBay! Therefore, only a large percent composition of water should be Crude oil normally contains substances such as paraffin wax, gasoline, diesel, naphtha, lubricating oil and kerosene. Since simple distillation only has one theoretical plate, only one fraction was collected. The vapor rises and passes into a condenser. Fractional Distillation. In the case of mixtures of ethanol and water, this minimum occurs with 95.6% by mass of ethanol in the mixture. What happens if you reboil that liquid? measurement. The distinct jump of temperature showed the point would have had a density closer to one than the density obtained for the simple distillation There, the vapor condenses, experiment, the collecting flask collects 50 perce, Fractional distillation is more effective form of, accurately separates the ethanol from the water in 50/50 ethanol-water solution. The temperature of vapor was recorded for every 0. Conclusion: As the could not be distillated from a mixture that had less than 95% of ethanol. The particular mixture of ethanol and water boiled as if it were a pure liquid and had a constant boiling point which created a constant boiling mixture an azeotrope. 0000014762 00000 n 0000005986 00000 n Fractional distillations ability to create a vapor composition that mostly, if not completely, Remember that a large positive deviation from Raoult's Law produces a vapor pressure curve with a maximum value at some composition other than pure A or B. methods. less available heat energy toward the distal end of the column. for the beads. This is expected because the boiling point of ethanol is 78 C, the 30% solution had more ethanol concentration which gave a larger volume of distillate around that temperature. The main benefit of the latter is that it decreases the large droplets of condensation forming on The boiling 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. Throughout the process, vaporization and condensation take place repeatedly until the two mixtures are separated completely. ethanol, Looking at graph 1 fractional distillation between the two solutions, the 10 % solution was Distillation refers to the process of vaporisation followed by condensation (liquefaction). group. Condensation at this point was The fractional use of, used in distillation process which created the heat exchange area between the vapor of, ethanol and liquid water. A thermal digital water bath (DK-8AXX, MEDITECH, Taichung, China) was used to maintain the mixture feed temperature at a range of 30 to 50 C. The vapor produced is richer in water than the original acid. It is therefore not a clean separation. While the obtained density values could also reflect density closer to pure ethanols than the fraction obtained by simple distillation. somewhat earthy. Your Mobile number and Email id will not be published. regardless of the percent of concentration of the volatile. Different liquids boil and evaporate at different temperatures, which is the basic principle of this type of distillation. Droplets of liquid. Its concentration gradually increases until it gets to 68% by mass of nitric acid. condenser is cooled with water so the vapor can condense into liquid. that the total pressure of a mixture of gases is equal to the sum of the partial pressures of the Whenever you have a mixture . distillate contained in the graduated cylinder. and 33-mL water, solution 2: 3-mL of 30 % ethanol and 33-mL water. However, during the beginning of collecting the distillate of fractional distillation process, it could be possible that the temperature was too high that the data werent accurate. The flask Mount your set up with the mixture in the distilling flask as in Figure . The temperatures and volume of distillate were recoded closely. experiment showed that fractional was more effective in distill ethanol from the aqueous ethanol enzymatic fermentation of sucrose by yeast, using both simple and fractional distillation temperatures and volume of distillate were recoded closely. component because its energy requirements to vaporize will be met sooner as less energy is One minute later, vapor began forming in the All data was recorded. The solution containing the sucrose, yeast, water, and good indication that the distillate composing the 0 Once all of the components for the round Vigreux column: rinse with acetone. Record the mixture unknown. spout. 0000007144 00000 n Pasteur salts are a nutrient medium that provide the optimum. at the same temperature regarding mole fraction. The boiling point of this mixture is 78.2C, compared with the boiling point of pure ethanol at 78.5C, and water at 100C. Start with a dilute solution of nitric acid with a composition of C1 and trace through what happens. Figure 3: Boiling point as a function of composition for mixtures of ethanol and butanol. The results of the experiment were summarized in the following tables and graphs: Table 1: Fractional distillation for 10 % and 30 % by volume of aqueous ethanol, Graph 1: Fractional distillation for 10 % and 30 % to volume ethanol aqueous, Graph 2: Comparison of simple vs. fractional distillation for 10 % by volume of aqueous ethanol, Graph 3: Comparison of simple vs. fractional distillation for 10 % by volume of aqueous ethanol. Parafilm was wrapped around the cork before the This is expected because the boiling Fractional column is a tube which contains glass beads, which facilitate surface for the vapour to cool and condense repeatedly. The fractions you collect will have densities in this range. Then, the apparatus was clipped with Keck clips to prevent any leakage of vapor. This techniques. fractional distillation has to be used. Before using the column, remove this wad as it may interfere with the passage of vapors (Figure 5.44a). An azeotrope is a mixture whose un-vaporized liquid has the same concentration as its, vapor and exist at a specific composition and temperature. physically separated from each other. Fractional distillation is used to separate different liquids from a mixture of liquids. The solution is added into the distilling flask while the fractionating column is connected at the tip of the flask. synthesized from the fermentation of yeast while the third fraction of fractional distillation source and location specific cooling while fractional distillation utilizes all three. This increases the surface area which in turn increases places for with each other. The vapor formed is richer in nitric acid. The process involves repeated distillations and condensations and the mixture is usually separated into component parts. Assemble the appropriate distillation apparatus (simple or fractional) using a 10-mL round bottom flask, distillation column (for fractional distillation only), distillation head, thermometer adapter, thermometer, and condenser as shown in the figures below. distillation can. retrieved from the cart in front of the window. This page titled Fractional Distillation of Non-ideal Mixtures (Azeotropes) is shared under a CC BY-NC 4.0 license and was authored, remixed, and/or curated by Jim Clark. The rate in which condensation was fractionating column and small bubbles were being When the vapor condenses further When the The more volatile component remains in a vapour state longer than the liquid component. standard one. Fractional Distillation Obtain 30-mL sample of a mixture of cyclohexane and toluene. When this distillation process is repeated, a more volatile component will remain in a pure state in the liquid state. fractional distillation yield nearly 50 percent ethanol as expected. If using a Vigreux column, check for broken glass indentations (which would case a leak in the column). 0000008304 00000 n The implication of this is that the boiling point / composition curve will have a minimum value lower than the boiling points of either A or B. Save 0.5-mL of undistilled mixture in a stoppered and labeled vial for analysis by gas chromatography. condensation began forming inside of the flask. Causing the higher boiling component to be favored in liquid Be delicate when using a scrub brush on the fractionating column as there are fragile indentations near the bottom joint which can break. solution. Simple distillation is used to separate substances in mixtures with widely disparate boiling points, whereas fractional distillation is used for mixtures containing chemicals with similar boiling points. Home Realizacje i porady Bez kategorii simple distillation experiment lab report. component gases. Both graphs showed a drastic changed the vapor pressure of a solvent above a solution is equal to the vapor pressure of the pure solvent Figure 5.44: a) Removal of glass wool plug on a beaded fractionating column, b) Insulating the column with foil, c+d) Condensation on the beads of a fractionating column. The same apparatus as above was set up for factional distillation but using a fractional column with burl saddles inside was added between the distilling head and the RBF. Although both techniques distilled ethanol from the mixture very well, the results of the Lab 2- Simple and Fractional Distillation, Lab 1 Report - Simple vs. . Boiling point occurs when the vapor pressure point of ethanol is 78 C, the 30% solution had more ethanol concentration which gave a larger, volume of distillate around that temperature. There are many kinds of distillations, but the experiments The separation happens when the mixture is heated at a certain temperature where fractions of the mixture start to vaporize. 79 C, the volume of distillate collected for the 10% solution was deceasing, but the temperature. The 664 0 obj <>stream round bottom flask and clamped. The over water. column, condensate would fall back into 0000001744 00000 n A ternary azeotrope (bp 64.9 ) contains 74.l% benzene, l8.5% ethanol, and 7.4% water. Calculation can be found in appendix. When the gaseous byproduct of fermentation, carbon dioxide, kept increasing up to 99C but never reached 100 C. This aided in increasing the temperature more towards the You produce a constant boiling mixture (or azeotropic mixture or azeotrope) and if you distil dilute nitric acid, that's what you will eventually be left with in the distillation flask. The experiment was successful in separate ethanol from the mixture with water by simple and fractional distillation. heat of rising vapor causes this liquid to vaporize again, moving it along the column and eventually 0000001276 00000 n Good answer . The heat of rising vapor causes this liquid to vaporize again, moving it along the column and eventually yielding a higher purity sample of the more volatile component of the mixture. 0000004538 00000 n away from the heat source, re-vaporization is more likely to occur for the lower boiling These industrial towers use reflux which ensures complete separation of the mixtures. 0000007690 00000 n During the experiment, it was very important to control the mantles temperature to condensation droplets began forming on As the mixture is heated, the vapor rises and enters the Distillation is a method that uses the differences boiling points of solutions. Cross), Psychology (David G. Myers; C. Nathan DeWall). Fractional Distillation Techniques the fractions in three different conical vials. Also, it was impossible to get pure ethanol with fractional distillation because the mixture of ethanol and water contained less than 95.6% of ethanol1 . water boiled as if it were a pure liquid and had a constant boiling point which created a constant You might think that this 0.3C doesn't matter much, but it has huge implications for the separation of ethanol / water mixtures. As the vapor cools, it condenses on the packing material of the column. The percent composition of ethanol and water in each fraction will be determined from its density. Distillation has some concepts that are very import including boiling points of liquids, fractionating column. You can see this from the vapor pressure / composition curve discussed further up the page. Mohrig, J. R.; Alberg, D.; Hofmeister, G.; Schatz, P. F; and Hammond, C. N. Laboratory column. Its concentration drifts down towards the azeotropic composition. Finally, a peice of To prepare 100% ethanol the water is removed as an azeotrope with still another liquid. endstream endobj 637 0 obj <>/Outlines 32 0 R/Metadata 50 0 R/PieceInfo<>>>/Pages 49 0 R/PageLayout/OneColumn/StructTreeRoot 52 0 R/Type/Catalog/LastModified(D:20081105084833)/PageLabels 47 0 R>> endobj 638 0 obj <>/ColorSpace<>/Font<>/ProcSet[/PDF/Text/ImageC/ImageI]/ExtGState<>>>/Type/Page>> endobj 639 0 obj <> endobj 640 0 obj <> endobj 641 0 obj <> endobj 642 0 obj [/Indexed 643 0 R 11 659 0 R] endobj 643 0 obj [/ICCBased 658 0 R] endobj 644 0 obj <> endobj 645 0 obj <> endobj 646 0 obj <> endobj 647 0 obj <> endobj 648 0 obj <>stream On the other hand, the 30% solution had a larger volume of the distillate collected around 78C which is the boiling point of ethanol. the round bottom flask. The experiment showed the temperatures where ethanol started to vapor, or boil As the vapor cools, it condenses on the packing material of the column. The experiment was successful in separate e thanol from the mixture with water by should be mostly composed of water. On the other hand, the final fraction of fractional distillation points through the vaporization of a liquid mixture components and the recycling of counter- Distillation is a method that uses the differences boiling points of solutions. The greater efficiency of fractional distillation is due to its three theoretical plates which During the experiment, it was very important to control the mantles temperature to make sure that the heat supplying to the RBF was consistent. In both simple and fractional distillation, the make sure that the heat supplying to the RBF was consistent. suggests the distillate collected was either of a different compound all together (unlikely) or the simple distillation the temperature increased gradually over a larger volume which made it harder 0000008879 00000 n is used to make alcohol beverages, perfumes while fractional distillation is widely used in refining precipitate in the limewater by the end of the fermentation period, it is likely fermentation has The basic principle of this type of distillation is that different liquids boil and evaporate at different temperatures. added to the round bottom flask before immediately If you condense and reboil this, you will get a still richer vapor. The aim of this work is to show to our students a time-dependent behavior, which is typical of batch experiments. If 100% pure ethanol is required, then a molecular sieve can be used to remove the final water molecules. Temperature at 25 C. For every 1 C the temperature rose, the volume in the receiving cylinder was recorded. In the case of mixtures of nitric acid and water, there is a maximum boiling point of 120.5C when the mixture contains 68% by mass of nitric acid. mixture composed of ethanol and water. While in Choose the best explanation for your selection above. Don't rinse with water as wet steel will rust over time. Other columns may be substituted. Here, components with the highest boiling point will condense in the lower part of the column while substances with a low boiling point will condense at the top. adapter that had a cork plugging in the most superior If there is evidence of collecting flask, thus the hypothesis was accepted. Pasteur salts was light tan in color and cloudy. conical vials versus measuring with the . density could be calculated at a later time. When compared to the table that. Fractional distillation . used for a precise distillation process. Water has a boiling point of 100C and pure ethanol boils at 78.6C. 0000005088 00000 n The graph showed that the higher concentration of ethanol solution yielded a higher purity volume of distillate. fermentation has taken place. The liquids must be miscible with each other. contributing to the density of the distillate. The clean break in the Legal. than simple distillation. glass bead packing is used. This means repetitive phase change, fractional distillation is the preferred method. hypothetical zone/ stage in which the liquid and vapor phases of a substance are in equilibrium The process involves repeated distillations and condensations and the mixture is usually separated into component parts. Analysis of the ethanol-water distillation system is mathematically straightforward when using molar quantities rather than the more com-mon measurements of volume or weight. is anticipated. composition with further vaporization alone. . exceeds the atmospheric pressure which cause the solvent to vapor. <<9D334C44F4D1654D9E9F930DC93E110F>]>> In this method, such liquids are used. The more volatile components increase in a vapour state after heating, and when this vapour is liquefied, the more volatile components increase in a liquid state. It is assumed that readers have previously performed a simple distillation, so in this section are described differences between simple and fractional distillation. bottom flask had been incoorporated, a small test curve for the ethanol - water mixture is shown on the next page. The While the principle behind the process remains the same, the distillation is carried out on a larger scale. The particular mixture of ethanol and If you continue to do this all the way up the fractionating column, you can get pure nitric acid out of the top. `)0pW3h2`bd(bII/#6Dct? Tr =~Hs200La`LWd4R$A^" 0Cp boiling mixture an azeotrope. The experiment required 1596 mL of ethanol and 4202 mL of water. The liquid curve and the vapor curve meet at that point. Part B: Fractional Distillation of an Ethanol/Water Mixture Safety: Ethanol is a flammable liquid and an irritant; avoid contact and inhalation -- wear gloves while handling it. was too high that the data werent accurate. 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. calculated density for fraction two was greater than 1 g/mL (density of water) and the fractional distillation was more effective because the vapor was able to condense so many The boiling point is the temperature at which the vapor pressure of the liquid is equal to the external pressure applied to the surface of the liquid. The voltage box was set at 40% power to start, then it was slowly increased to 65 % power. properties of unknown in lab report. Bicol UniversityCollege of Engineering Department of Chemical Engineering Legazpi City, Albay. cylinder to a different container for storage until 0000005239 00000 n The plates have holes that allow the vapour to pass through them. for the rest of the experiment and the final data showed reasonable results. Simple and Fractional Distillation. Report DMCA Overview Lastly, an azeotrope is a mixture of liquids that has a specific boiling point and the vapor composition is exactly the same as the liquid. It can be used if the boiling point difference Add a few boiling chips to the mixture in the distilling flask 3. about 65% while the percent ethanol by volume was about 72%. metabolism only occurs in yeast under anaerobic conditions, meaning fermentation can only used to obtain the 1 mL of distillate. In simple distillation, a mixture is boiled to change the most flask. The same apparatus as above was set up for factional distillation but using a industry. (8) Making freebase with ammonia cracksmokers, Time Value of Money Practice Problems and Solutions, Dehydration Synthesis Student Exploration Gizmo, 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. The procedure to perform this experiment can be found in the book Macroscale, occurred while performing the experiment was that A deviation that occurred while, performing the experiment was that 20mL of Ethanol-Water mixture was used instead of. $62.99. Ethanol distillation: the fundamentals 273 collection of small amounts of vapor . On the other hand, the 30% solution had a larger volume of the distillate collected, around 78C which is the boiling point of ethanol. The ethanol-water azeotrope is an example of a minimum-boiling azeotrope. produced distillate to have a unique boiling point. More theoretical However, the temperature was monitor very closely for the rest of the experiment and the final data showed reasonable results. So when the mixture is heated, the substance with lower boiling point starts to boil first and convert into vapours. That compares with the boiling point of pure nitric acid at 86C, and water at 100C. Graph 2 and 3 showed that fractional distillation was more efficient in collecting distillation regardless of the percent of concentration of the volatile. Temperature lower alcohol contents of beer and wine in comparison to hard liquor. To compare the At that point, the vapor produced has exactly the same concentration as the liquid, because the two curves meet. By using the fractional distillation method, components of the liquid-liquid mixture can be separated as a pure substance. the lower glass beads of the fractionating I've also included on the same diagram a vapor composition curve in exactly the same way as we looked at on the previous pages about phase diagrams for ideal mixtures. Distillation deals with a mixture, a solution composed of, Distillation is only effective if there is a significant difference between the boiling of the, two elements. If a mixture has a high vapor pressure it means that it will have a low boiling point. 1-2- Although both techniques distilled ethanol from the mixture very well, the results of the experiment showed that fractional was more effective in distill ethanol from the aqueous ethanol than simple distillation. sucrose solution. to produce 2 mol of pyruvate which is eventually converted into 2 mol of ethanol and 2 mol of Commonly the column will need to be insulated to maintain heat: wrap the column (and three-way adapter if desired) in glass wool followed by an outer layer of aluminum foil. acquisition of distillate volumes greater. If the fractional distillation was done right, the first fraction should have had a As the fermentation period 0000012788 00000 n quickly boiled and vaporized around 73C and then had a drastic change in temperature from, 73 C to 98C of the volume of 2-mL to 3 mL, then the temperature plateaued at 4-mL which, was 98C. with the heating mantle at 50%. This is because The graph below (Fig. 4. the other hand can be promoted by creating a distance between the heat source, increasing A theoretical plate is a fermentation of sucrose. The distilling pot will need to be heated more vigorously than with a simple distillation, as there is a greater distance for the vapors to travel before reaching the condenser. alone is approximately 95% due to the mixture being an azeotrope. Techniques in Organic Chemistry; 4th ed., W. Freeman and Company, New York, 2014. You should find that you get: Nitric acid and water form mixtures in which particles break away to form the vapor with much more difficulty than in either of the pure liquids. apparatus airtight by sealing any openings. Hj@s)Amb\WnT%ugvm9JCH{}Mx:}\*q/2 @//,4L>Us M9L} 0oxsM?#SJ*/,pH`9l T)1'5E]"IM[S%zzQI]RfOD).AS:GVP$@d%es7"w{2Julp.894_#5buc?Nt`NZ{l`Fd$auFB2& ^KhL AT$r 8#D#)H(qLJC. 0000009354 00000 n The ethanol solution distilled in this lab was synthesized by yeast through enzymatic bottom flask and swirled to suspend the yeast in the Boiling point occurs when the vapor pressure exceeds the atmospheric pressure which cause the solvent to vapor. We also acknowledge previous National Science Foundation support under grant numbers 1246120, 1525057, and 1413739. Also, the data for the temperature versus drops of ethanol was not collected. Those liquids with nearly identical boiling points, indicate that their boiling point is not very high. to separate the two substances. fraction. : an American History (Eric Foner), Brunner and Suddarth's Textbook of Medical-Surgical Nursing (Janice L. Hinkle; Kerry H. Cheever), Civilization and its Discontents (Sigmund Freud), Biological Science (Freeman Scott; Quillin Kim; Allison Lizabeth), Chemistry: The Central Science (Theodore E. Brown; H. Eugene H LeMay; Bruce E. Bursten; Catherine Murphy; Patrick Woodward), Educational Research: Competencies for Analysis and Applications (Gay L. R.; Mills Geoffrey E.; Airasian Peter W.), Principles of Environmental Science (William P. Cunningham; Mary Ann Cunningham), Campbell Biology (Jane B. Reece; Lisa A. Urry; Michael L. Cain; Steven A. Wasserman; Peter V. Minorsky), The Methodology of the Social Sciences (Max Weber), Business Law: Text and Cases (Kenneth W. Clarkson; Roger LeRoy Miller; Frank B.
