Determination Of Solubility Of Polar Solutes

There are various techniques to separate a mixture of compounds from each other. One of the commonly used way to isolate compounds from a mixture of two compounds is called extraction. This method of extracting two compounds from each other relies on the different solubility of the compounds in two different solvents.

Experiment 55 consists of devising a separation and purification scheme for a three component mixture. The overall objective is to isolate in pure form two of the three compounds. This was done using extraction, solubility, crystallization and vacuum filtration. The experiment was carried out two times, both of which were successful.

Me and my lab partner, obtained a mixture of a un known proportion from the instructor and then flow the guide line in our lab manual to separate the mixture by applying the separation method motioned in our lab manual pages 33-40 . In this experiment, the separation methods were decantation,

There are millions of different organic compounds. Most of them are found in mixtures and in order to achieve a pure form they need to be separated, isolated, and purified. However, there are endless numbers of possible mixtures, which make it impossible to have a pre-designed procedure for every mixture. So chemists often have to make their own procedures. The purpose of this experiment was to prepare the student to the real world by them designing their own procedure which will help them understand the techniques of separation and purification better. The goal was to extract two of the components of the

The objective of this extraction experiment was to achieve a comprehensive understanding, as well as master the practice, of the technique of separating various individual components of a compound.

6. The solubility of the solids were tested using a micro tray, by placing them in water and oil to observe their polarity,

In the beginning of this experiment, our TA added water, salt, and 75/25 hexane/acetone to spinach leaves to a blender and blended the mixture to assume equal amounts for each group and to avoid erros if each student had to do the blending. The addition of the water to the mixture allowed the it to separate into a distinct organic layer after being run in a centrifuge, which was available to be collected at the top of the centrifuge. Salt reduces solubility, which will force the organic parts of the mixture (the desired pigments for example) to separate into the organic layer at the top. Lastly, 75/25 hexane/acetone is added because this is a moderately polar solvent and will useful for both the non-polar and polar pigments present within the spinach leaves. A mixed solution of hexanes and acetone must be used because acetone is very polar, while hexane in very non-polar, and the spinach leaves contain both non-polar and polar pigments in them that are important in the extraction and for further analysis. The mixture was placed in the centrifuge so the solids in the mixture (mostly cellulose) could be separated from the liquids into separate distinct layers for further extraction and testing. In the tube, the organic substances separated into the top layer, whereas the water layer remains at the bottom of the tube below the solid layer made up of mainly cellulose.

Objective: The objective of this experiment is to use acid-base extraction techniques to separate a mixture of organic compounds based on acidity and/or basicity. After the three compounds are separated we will recover them into their salt forms and then purify them by recrystallization and identify them by their melting points.

Experiment 4A: Determination of a Partition Coefficient for Benzoic Acid in Methylene Chloride and Water, and Experiment 4B: Solvent Extraction I: Acid-Base Extraction Using the System Benzoic Acid, Methylene Chloride, and Sodium Bicarbonate Solution

The eluting solvent passed down the column by the gravity and an equilibrium was established between the solute absorbed by the absorbent (silica gel in this experiment) and the eluting solving flowing down. Since the components in the sample had different polarity and they interacted with the stationary phase and the mobile phase differently, the components would be carried by the solvent to a different extent and a separation of the components could be achieved.

In this experiment, separation of fluorene and 9-fluorenone took place using column chromatography. The pureness of the separate compounds was checked using TLC and melting point analysis. Rf values were the determined from the TLC plates and calculated to compare the experimental Rf values to the starting mixture Rf values. TLC is useful to separate tiny samples and is considerably quick, while chromatography is used to separate considerably larger mixtures but takes more time. The melting point of both desired molecules was found and contrasted with the actual values. The melting point is used to assess the purity of each compound recovered. Column chromatograpahy separates compounds based on polarity. Column chromatography contains a mixture dissolved in solvent and put in a column that had solid adsorbent and an eluent. There are different phases in the column: a polar stationary phase (solid adsorbent), the alumina, and mobile phases (eluent), which can flow throughout the column. There are different phases due to different polarities, resulting in dissimilar bands. TLC separates compounds due to polarity. Each sample is dotted on the plate and placed in eluent and the samples quickly separate due to polarities and adsorption. The spots can either move far or short distances. The weakly adsorbed compounds move faster than the stronger adsorbed components. The textbook mentions simple elution stepwise elution to elute each fraction in the column chromatography. Simple

The objective of this lab was to separate a mixture that consisted of elements and compounds. There are seven ways to separate a mixture which included paper chromatography, filtration, evaporation, simple distillation, fractional distillation, magnetism, and separating funnel. The only methods used in this lab were filtration, evaporation, magnetism, and separating funnel. The method of magnetism was used when the magnet was moved under the mixture to separate the iron. The process of filtration involved the use of a filter paper placed in a filter funnel. The funnel was placed in a beaker and the mixture of water, sand, and sodium chloride was poured into the funnel. The liquid part drained through the filter paper into the beaker, leaving the solid sand particles trapped on the filter. After the water and sodium chloride were in a beaker, the process of evaporation was used. The compound was boiled on a hot plate, which led to the water

The purpose of this experiment was to use solvent extraction techniques in order to separate a mixture consisting of a carboxylic acid (p-toulic acid), a phenol (p-tert-butylphenol), and a neutral compound (acetanilide). Extraction is the process of selectively dissolving one or more of the compounds of a mixture into an appropriate solvent, the solution that contains these dissolved compounds is called an extract (Manion, 2004).

The compounds are separated by collecting aliquots of the column effluent as a function of time.

As mentioned in the discussion, olive oil, vegetable oil, crisco, and lard were soluble in nonpolar solvents and insoluble in polar solvents. This is due to the chemical composition of polar and nonpolar substances which results from the molecular shape as well as properties of dissolving solutes in solution. Polar substances are hydrophilic and contain polar Van Der Waals interactions (intermolecular forces) such as dipole-dipole forces, ion-dipole forces, and hydrogen bonding. Nonpolar substances are hydrophobic and contain non-polar Van Der Waals interactions. ‘Like dissolve like’ is the reason only polar solutes dissolve in polar solvents and why nonpolar solutes dissolve in nonpolar solvents. Molecules with similar polarity have similar intermolecular forces and therefore, can interact with each, or in this case dissolve9. Additionally, the solubility of a compound is determined by the length of the hydrocarbon chain. Long hydrocarbon chains such as the one found in oleic acid makes a compound more insoluble10. Therefore, since the lipids used in this experiment were hydrophobic substances and each lipid has long hydrocarbon chains, the results were consistent with the scientific literature and principles.