Surface Chemistry of Silica

Aim: The aim of this experiment is to observe how by increasing the temperature of sodium thiosulfate in a solution with 2.0 molar Hydrochloric acid can affect the rate of reaction and the rate in which a precipitate is formed.

In this experiment, the Fischer Esterification of an unknown acid and an unknown alcohol was used to prepare an unknown ester. Sulfuric acid was used as a catalyst in the reaction which then was put under reflux. After cooling, the pH of the solution was raised to approximately 8 using sodium carbonate. Diethyl ether was added, then the aqueous layer was removed and the organic layer was washed with sodium chloride. The aqueous layer was removed again and sodium sulfate was added. The unknown product was then identified using gas chromatography (GC) to obtain the retention time.

Adsorption area (peak) are present at a wavelength of 1454.33 cm-1 in the ACS adsorbent without activation identifies alkanes in the C-H stretching group, where physical activation and chemical activation eliminates a large amount of hydrogen from the adsorbent. The stretching group of C=O at a wavelength of 1707 cm-1 indicate that physical and chemical activation cannot detach ester completely from the adsorbent surface. Overall, there are a number of active sites with hydroxyl and carboxylate functional groups on the surface of the ACS adsorbent that able to adsorb metal ions Cd (II).

Osmosis is the passive movement of water from an area of low solute concentration to an area of high solute concentration, normally across a membrane which prevents the movement of solvent. This is a process by which materials may move into, out of, or within cells. Osmosis doesn’t depend on energy provided by living organisms but is affected by the properties of the cell membrane. The rate of osmosis is dependent on such factors as temperature, pressure, molecular properties such as size and mass, and the concentration gradient. In osmosis, the relationship between a solute’s concentration outside of cell and inside of a cell is described in terms of the tonicity of the solution outside of the cell. A cell is in a hypotonic solution when the solute is more concentrated inside the cell and therefore water moves into the cell. In this solution the cell swells as water enters, this may continue until it ruptures or hemolyzes. In the reverse condition, the cell is in a hypertonic solution

Finally ensure that your results are accurate. You should have a light blue precipitate remaining when the sodium carbonate reacts with the copper chloride and when sodium sulphate ionises with copper chloride no precipitate should have formed.

Hake, Stephen & Saxon, John. (2004) Saxon Math 5/4 Student Edition. Saxon Publishers, Inc., and Stephen Hake

Seven test tubes were labeled numerically with 2 mL of VO3- and H2SO42- added to each tube. A small pea size portion of solid Na2SO3 was added to the first test tube. Then, 20 drops of distilled water were added to the second test tube. In the third test tube, 20 drops of (.2 M) NaBr were added. Then, to drops of (.2 M) NaNO2 were added into the fourth test tube. A small portion of Fe(NH4)2(SO4)2 * 6H2O was added into the fifth test tube. The sixth test tube had 20 drops of (.2 M) H2Cr2O4 added, where the seventh test tube was the control tube with no additional chemicals added. All the test tubes were left to react for 3 minutes and then heated in a heated bath for approximately 20 minutes.

Dissolve 2.34 g of cobalt chloride hexahydrate (CoCl2.6H2O) in 100 ml of water in an Erlenmeyer flask. While stirring the oxalic acid solution constantly, add the cobalt chloride solution drop by drop. Let the mixture cool in an ice bath. A precipitate will form slowly.

As it is a special method of diffusion exclusive to water, it also allows dilute and concentrated solutions to balance their strengths. It does this by preventing large non-water particles from passing through the semi-permeable membrane due to their size, in order

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.

The Fe-Co deposit obtained from ethaline and reline was successfully deposited on a copper substrate by maintaining a steady potential of 3.0 V at 60℃ for 2 hours. The Fe-Co coating from reline was dark black in colour, whereas the Fe-Co coating from ethaline appeared to show a tint of grey on the surface. The Fe-Co deposits in both liquids were smooth and uniform. Figure 6.3 a and b show the SEM images of Fe-Co deposited from ethaline and reline. It is clear from the images that there is a variation in morphology from both liquids. The Fe-Co coating from reline appears to show a more nodular shaped structure which is evenly spread on the surface of the copper substrate when compared to Figure 6.3 a.

By using the principle of LeChatlier, one can determine the two Cobalt forms - CoCl4 2- and Co(H2O)6 2+. In order to determine whether or not the solution will shift left or right with respect to equilibrium, it is based on Cl-. However, when silver nitrate was added to bis(tetraethylammonium), it showed that Cl- was reduced in the given solution. This ultimately caused the synthesis of the product turned it a pink color. When given a blue color, it was determined that tetraethylammonium Chloride was involved with the stock solution, which ultimately caused the Cl- to form the reactants. Finally, based from the results, it is shown that CoCl4 2- is blue, and Co(H20)6 2+ is pink.

In normal micelles, the hydrophobic hydrocarbon chains of the surfactants are directed toward the internal of the micelle, and the hydrophilic groups of the surfactants are in contact with the surrounding aqueous middle. Above the cmc, the physical state of the surfactant molecules changes significantly, and extra surfactant exists as aggregates or micelles. The bulk attributes of the surfactant change around the cmc, such as osmotic pressure, turbidity, solubilization, surface tension, conductivity, and selfdiffusion. On the other hand, reverse micelles are formed in nonaqueous medium where

Within every cell, a movement of a solvent occurs through a semipermeable membrane to equalize the concentration of solute on both sides of the membrane. The diffusion of water across the cell’s membrane down to its concentration gradient is called osmosis. In this case, the concentration gradient is the difference of density between one side of the cell membrane to the other. Since the cell’s membrane is permeable, particles can flow freely in and out of the cell, but the net flow will be strong in the direction of lower concentration until the system has reached a stage of equilibrium, the point at which both sides of the membrane are equal. In the

Solutions of CuSO45H2O (0.506 g in 10mL water, 3.17E-3 mol) and ammonium peroxodisulfate (1.030 g in 10mL water, 4.51E-3 mol) were prepared and mixed