Lab 2 - Lab 2 Investigating Solubility and Acid-Base...

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Lab 2: Investigating Solubility and Acid-Base Reactions Purpose The purpose of this lab is to investigate the solubility of various compounds and how acid base properties affect solubility. Discussion Part 1: Solute Miscibility with Non-polar Solvent Hexane is a non-polar alkane that interacts with other molecules via Induced Dipole- Induced Dipole (ID-ID) or London dispersion forces. Diethyl ether is non-polar, hence miscible with hexane. Dichloromethane is itself polar, yet non-polar enough to mix with hexane due to its alkane chain. Ethyl acetate, acetone, ethanol, and water are all polar, which makes them immiscible with hexane. Part 2: Solute Miscibility with a Polar Solvent Water is a polar molecule that interacts with other substances via polar H-O hydrogen bonding (a strong dipole-dipole interaction). Diethyl ether and toluene are non-polar, hence immiscible with water. Dicloromethane has a polar section but is immiscible with water due to the non-polar alkane group. Acetone, ethyl acetate, and ethane are all polar, therefore are miscible with water. Part 3: Water Solubility in Alcohols The solutions of ethanol with water and 1-propanol with water are miscible. The solutions of 1-butanol and 1-pentanol are not miscible with water. The data indicates that the solubility is reduced in larger alcohols. This is due to the fact that as nonpolar alkane chain increases in length, the intermolecular forces between the non-polar molecules overcome the dipole Induced Dipole (D-ID) moment. On the other hand, the smaller alcohols are miscible because they have less alkane group and therefore can interact with water through Dipole-Dipole (D-D) forces between the H-O bonds in water and alcohol. Part 4: Temperature Dependence of Solubility At the starting room temperature, benzoic acid remains as solid crystals because the non-polar portion is unable to interact with the polar D-D in water. However, as the solution is heated, the heat disrupts the intermolecular forces between the benzoic acid molecules. The loosened benzoic acid molecules then interact with water via D-
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This note was uploaded on 07/23/2010 for the course CHEM Chemistry taught by Professor Nitche during the Spring '08 term at Berkeley.

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Lab 2 - Lab 2 Investigating Solubility and Acid-Base...

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