The Investigation Of Vanadium 's Redox States

3. Turned off the laboratory burner and observed the properties of the product in the evaporating dish.

A 0.5 g of sodium tungstate dihydrate was weighed and transferred into a 50-mL round-bottom flask with a magnetic stir bar. Approximately 0.6mL of Aliquat 336 was then transferred carefully into the round bottom flask using a 1mL syringe. The round bottom flask and its contents were then set up in an oil bath. 11mL of 30% hydrogen peroxide and 0.37 g of potassium bisulphate were added to the reaction mixture in the round bottom flask and stirred using a magnetic stirrer. Lastly, 2.5mL of cyclohexene was added using automatic dispenser and the mixture stirred. A condenser was fitted on the round bottom flask, clamped and attached to water horses. The reaction mixture was then heated on the oil bath and the reflux process initiated for an hour while stirring the mixture vigorously. Half way while rinsing, any trapped cyclohexene in the condenser was rinsed. After 1 hour, the round bottom flask was rinsed

The objective of the experiment was to observe different reactions with different chemicals. The experiments emphasized on the chemical changes occurring in acids and bases as well as color changes and bubble formations. The experiments allowed for a better understanding of the undergoing chemical changes in mixtures. Some mixtures instantly changed colors while others were transparent or foggy. Some mixtures produced thick color that created solids called precipitates. Mixtures KI + Pb(NO3)2 and NaOH + AgNO3 both produce noticeable precipitates after a while. It was interesting to see the different acidic and base reactions like the fuchsia color formation in NaOH + phenolphthalein.

Helium, a noble gas, is the second most abundant element in the universe. It was discovered on the sun before it was found on earth by French astronomer Pierre-Jules-Cesar Janssen in 1868. Helium received its name from the Greek word for sun, helios. Even though helium is so abundant throughout the universe it is relatively rare on Earth.

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Based off of prior knowledge the hypothesis for Lab six was that the first reaction would produce Lead Iodide, the second reaction would produce Copper II sulfide, and the third reaction would produce Iron II Hydroxide. For the unkonown solution B this hypothesis was incorrect. Based off of the calculations and the color observations the the metal product present in the first reaction was Silver Iodide, the product present in the second reaction was Copper II Sulfide, and the product present in the third reaction was Nickel II Hydroxide. Although the hypothesis was incorrect the experiment was a success because the ultimate goal were reached. The lab was created to generate understanding of solubility and stoichemtry. Through observation of

Mercury is a transition metal that is also known as “quicksilver.” No one is sure who discovered this element. Mercury has been used since ancient times; the Chinese, Egyptians, and the Hindus have been known to use mercury. In 1500 B.C. mercury was found in ancient Egyptian tombs. There also has been writings found that have said “liquid-silver” and “water-silver” written by Aristotle in the fourth century B.C.

Russian chemist Dmitri Mendeleev predicted the main properties of Gallium before its discovery and existence. Mendeleev named the element eka-aluminum because, as he predicted, the element would be placed right below aluminum on the periodic table. The discovery of Gallium was made spectroscopically in 1875 by French chemist Paul E. Lecoq de Boisbaudran through a spectroscope. Paul Lecoq de Boisbaudran found a new violet line in the atomic spectrum of zinc. He knew it meant that an unknown element was present. Boisbaudran had isolated and purified the new metal (through electrolysis of its hydroxide in a potassium hydroxide solution) by November in 1875. The origin of the name ‘Gallium’ comes from the Latin word ‘Gallia’, meaning

Thorium is a radioactive, solid silvery metal prior to its melting point of melting point of 3300°C. Thorium has an atomic number of 90, placing it two positions behind Uranium, on the periodic table. This is one of the two rare radioactive metals (the other being Uranium) that can be found in high quantities in the earth's crust with the majorly commercial mineral monazite, or it can be rarely found naturally in its oxidized form. Pure thorium looks silvery white and is very delicate, but will harden by the time it has reacted with the atmosphere, which takes several months. Once it starts to react, it's outermost later will undergo a form of corrosion with the atmosphere, tarnishing it black.

A potential set-up was prepared wherein the 25 x 150 mm test tube was filled with K2SO4 (30mL, 0.15 mol) saturated at 0 °C in 5M H2SO4. The test tube was immersed in ice, power supply was adjusted to give the solution a current of ~3.0 amps. Current was read and recorded as accurately a possible, as well as the time over which electrolysis was carried out. K2S2O8 precipitated over a period of 45-50 minutes during which the temperature was maintained close to 0 °C (~8 °C or lower) during electrolysis.

Electrochemistry is a vital part of the world and affects most individuals on a daily basis. Without electrochemistry and the knowledge gained from it, there would be no batteries, no cars, no electronics and many other things that depended on a power source. One of the main ideas is that of concentration cells. Concentration cells essentially make a battery by using different concentrations of compounds to have a positive cell potential. If something is a battery meaning, it has a positive cell potential and therefore it is also a “voltaic” cell or “galvanic” cell and reduction occurs spontaneously. When looking at redox reactions it is important to understand that the cathode is where reduction occurs and the anode is where oxidation occurs as all areas of electrochemistry depend on cathodes and anodes. The cell potential of a cell is a measure of the difference between the cathode and anode of a reaction and is found by subtracting the cathode minus the anode using the table of standard half reactions . Using cell potentials it is possible to find what a certain unknown material is present in the cathode or anode. If one wishes to calculate the theoretical potential of a cell then the Nernst equation can be used if both half-cell concentrations are known, or the concentration of a product or reactant can be calculated if the potential is known. This experiment highlighted these main pints of electrochemistry by incorporating unknown substances and concentrations which

period. The results were compared against standard curve developed using a concentration gradient of Na2So4 with BaCl2 (De Zoysa et al., 2007).

Today, the periodic table is used by many people worldwide to learn more about the elements located on it. It has evolved into a much easier piece of information to use because of all the many scientists and chemists that have revised it over the last hundred ish years. There are certain things on the periodic table that help to learn more about each element. Periodic families are used to help understand similarities between the atomic structures of elements. Trends are used to show certain patterns within the periodic table. One can learn many things about the periodic table from studying it.

Tantalum is a silver reflective rare earth element that is used in both the electronics and engineering industries. It is an extremely useful element and is a vital part in modern life. Tantalum is found in columbite-tantalite ores. Many countries don’t have high grade Tantalum and have to recycle and import it from other countries such as Australia, Kazakhstan, Canada, China and Thailand. It is a very used element that has been a giant boost in technological advancement.

The colour of the precipitate was black and were quite small in size, so it was a bit hard to distinguish between the zinc powder present and the copper formed by the displacement reaction because copper formed should be reddish brown is colour – which is also a dark colour and thus two dark colours were hard to be distinguished.