The Partition Coefficient (Kp) Excretion of Benzoic acid and its conjugate Base from Two Immiscible Phases Abstract: The partition coefficient is the ratio of concentrations of compounds in the two phases of a mixture of two immiscible solvents at equilibrium. The purpose of this experiment is to determine the partition coefficient of benzoic acid first in water with methylene chloride, and then in sodium bicarbonate solution with methylene chloride. The partition coefficient result for Part A (water with methylene chloride) was 3, while the result I got for Part B (methylene chloride with sodium bicarbonate solution) was 0.55. Both results correlate to the ideal values which were greater than 1 for part A, and less than 1 for part B. In each of these separations, when the layers were allowed to settle and mixed together, two different …show more content…
Discussion / Conclusion: The purpose of this lab was to calculate the partition coefficients in a mixture of benzoic acid, methylene chloride, and water, as well as a mixture of benzoic acid, methylene chloride, and sodium carbonate solution. While observing the partition coefficients, parts A and B are very different. Molecules having their own solubility levels as well as properties were the result of the different partition coefficients. In this experiment, benzoic acid will end up dissolving differently in each solvent that is added. In part A, I was able to determine that both molecules in the mixed solution have similar degrees of polarity. Methylene chloride and water are both polar, as is benzoic acid, however, both benzoic acid and methylene chloride are only slightly polar. They are very similar in chemical properties because they are just slightly polar. Why benzoic acid is high in mass is explained by the similarity in chemical properties, and the reason the partition coefficient is greater than 1. Mine resulted in a partition coefficient of
Organic modifiers are used to change the retention time of different analytes. Organic modifiers lower mobile phase polarity. By increasing the amount of water lead to the repulsion of hydrophobic analytes out of the mobile phase. The hydrophobic analytes are pushed onto the stationary phase where they reside for duration up to the partitioning into the mobile phase. When ionic analytes exist in the sample, the addition of ion and buffer to the mobile phase are necessary.
Question3: Experiment 3 The unknown acid sample was 1 • Monoprotic Acid Trails Initial NaOH solution (mL) final NaOH solution (mL) The volume of NaOH to titrate the acid (mL) Amount of Unknown Acid sample 1 (g) The moles of the Unknown Acid (mol) Molar mass of the Unknown Acid (g/mol) A 3.38 28.31 24.93 0.150 0.0026 57.69 B 0.18 29.32 29.14 0.175 0.0029
In the first part of the experiment, Part A, the standard solutions were prepared. As a whole, the experiment was conducted by four people, however, for Part A, the group was split in two to prepare the two different solutions. Calibrations curves were created for the standard solutions of both Red 40 and Blue 1. Each solution was treated with a serial 2-fold dilution to gain different concentrations of each solution.
To begin, the solubility of the unknown compound in water was tested. If the compound is soluble in water, it can be inferred that it is either a polar covalent or ionic compound.
Beneath Our feet Experiment 1: We put different types of rocks in to three piles that were called Igneous, Metamorphic and Sedimentary. Igneous comes from a volcano. Metamorphic is heat and pressure and Sedimentary is a mixture of conglomerate, fossils and layers. Experiment 2: We put chalk and 3 spoons of sand into a cup and shook it really hard. Some of the sand turned pink which was the colour of the chalk.
Determining Unknowns Through Distillation Introduction Distillation is a technique of separating two miscible liquids by their boiling point differences. This experiment uses distillation to separate and identify two unknown compounds. The two types of distillation are simple and fractional. Simple distillation is used to separate miscible liquids that have a boiling point difference of 100 C or more, while fractional distillation is used to separate miscible liquids that have a boiling point difference of less than 100 C. Simple distillation and fractional distillation have two similar but different apparatuses. The fractional apparatus is set up the same as a simple apparatus, but a column packed with steel wool is added in between the boiling
It also confirmed the idea that molar mass of a solution could be determined through the freezing point depression formula as long as one knows the freezing point depression constant of the solvent used, the mass in kilograms for the solute-solvent mixture, and the change in freezing point from the addition of a solute. Lab Questions: What is the freezing point for lauric acid? What is the melting point for lauric acid? The freezing point for lauric acid in this experiment was 43℃.
After obtaining an homogeneous mixture, the flask was placed in an ice bath during five minutes next to a graduated cylinder containing 5.0 mL of concentrated sulfuric acid. The temperature of the ice bath was recorded to be 1.1 °C. Likewise, a second graduated cylinder containing 1.8 mL of nitric acid and 2.5 mL of sulfuric acid was immersed in the cold ice bath to keep the three different solutions at the same temperature. Thereafter, the cold 5.0 mL of H2SO4 were added to the erlenmeyer flask containing the acetanilide solution, which remained in the cold water for approximately another 4 minutes.
The three-component mixture was separated through the isolation of each individual component. The isolation process began with o-toluidine, which utilized the addition of hydrochloric acid, sodium hydroxide, and dichloromethane—to the mixture—for the formation of an organic layer that contained pure o-toluidine. Then, the addition of sodium hydroxide and hydrochloric acid to the remaining mixture resulted in an organic layer, which contained pure benzoic acid precipitate. Finally, anhydrous magnesium sulfate and methylene chloride were added to the remaining mixture of anisole, which resulted in a pure anisole because it removed all residual water and boiled off excess methylene chloride used. The percent recovered from extracted anisole, benzoic
PChem Experiment No. 3 Cryoscopic determination of molecular weight 1. Aims To determine the apparent molecular weight of benzoic acid in cyclohexane by creating a binary system and finding the different freezing points of the solutions. 3. Experimental Procedure A dry, empty freezing-point tube and its cork were weighed together.
The reaction mixture: R_F=2.9/4.5 = 0.64 The final product: R_F=1.9/4.5 = 0.42 Table of calculations Benzaldehyde Acetone Sodium Hydroxide Ethanol Dibenzalacetone Co-efficient 2 1 1 1 1 Volume (ml) 4.04 1.5 30 Grams used (g) 4.2 1.185 4 0.95 2 Formula weight (g/mol) 106.12 58.08 40 46.07 234.29 Moles 0.0396 0.02 0.1 0.02 Moles/ Coefficient 0.02 0.02 0.1 0.02 Density 1.04 0.79 (1) Calculations Mass Impure compound mass: 2.02g Final compound mass: 2.88g Dibenzalactone = (4.2×234.29×1)/(106.12×2) = 4.64g (theoretical
Experiment Description: To begin the experiment, 2.0718g of a benzoic acid and p-dichlorobenzene mixture and 30 ml of methylene chloride was placed in a separatory funnel. The funnel was shook to dissolve the contents. After shaking, the funnel was inverted and the stopcock was opened to release the pressure. The stopcock was closed, the funnel was shook, and the pressure was released again. This was repeated until no more gas was released.
When separating the two layers, some of the top aqueous layer flowed out with the bottom layer. This caused slight impunity in the compounds. In the first separation step, the escape of the clear top layer resulted in less benzoic
Data suggests that Water is the best solvent that will allow for better saturation and the best recrystallization of benzoic acid, this is largely due to water being a polar molecule whose properties allow for carboxylic acid groups, such as the one found in benzoic acid, to disassociate and donate protons to the water
Abstract The unknown concentration of benzoic acid used when titrated with standardized 0.1031M NaOH and the solubility was calculated at two different temperatures (20◦C and 30◦C). With the aid of the Van’t Hoff equation, the enthalpy of solution of benzoic acid at those temperatures was determined as 10.82 KJ. This compares well with the value of 10.27KJ found in the literature.