General Principles & Processes Of Isolation Of Elements

Aluminum is the most abundant metal in the earth's crust. It makes up about 8% of the crust by weight. It is found in various minerals and rocks, such as bauxite. Aluminum is widely used in various industries due to its low density, corrosion resistance, and high strength-to-weight ratio. It is commonly used in construction, transportation, packaging, and electrical applications.

Gravity separation is a process in which an upward stream of running water is used to wash the powdered ore. This technique relies on the difference in density between the ore particles and the gangue particles. The heavier ore particles settle at the bottom while the lighter gangue particles are carried away by the upward stream of water. This allows for the separation of the valuable ore from the unwanted gangue material.

Gibb's Energy is used to make interpretations and predict which element will suit as the reducing agent for a given metal oxide. This is because Gibb's Energy is a measure of the spontaneity of a reaction and can determine whether a reaction is favorable or not. By comparing the Gibb's Energy of the metal oxide and the potential reducing agents, one can predict which element will be able to reduce the metal oxide and form a more stable compound.

Dolomite is the correct answer because it is a type of sedimentary rock that contains both calcium (Ca) and magnesium (Mg). Limestone, on the other hand, typically contains calcium but not magnesium. Chalk is mainly composed of calcium carbonate but does not contain magnesium. Feldspar is a group of minerals that does not contain either calcium or magnesium. Therefore, dolomite is the only option that contains both Ca and Mg.

Pine oil is used in the Froth Floatation Process to enhance the non-wettability of the mineral particles. This means that it reduces the ability of the mineral particles to be wetted by water, which is important for the separation of minerals from the ore. By making the mineral particles less wettable, they are able to attach to air bubbles in the froth and float to the surface, while the gangue particles sink. This helps in the recovery of the desired ore particles and the separation of two sulphide ores.

Clay is an ore of aluminum because it contains a high percentage of aluminum minerals such as kaolinite and montmorillonite. These minerals are formed through the weathering and decomposition of aluminum-rich rocks over millions of years. Clay is widely used in the production of aluminum because it can be easily processed to extract aluminum oxide, which is then further processed to obtain pure aluminum metal.

CaO, also known as calcium oxide or quicklime, is a drying agent that reacts with CO2 and removes water vapors. It has a strong affinity for water and readily reacts with it to form calcium hydroxide (Ca(OH)2). The reaction between CaO and CO2 produces calcium carbonate (CaCO3), which is a solid and can be easily separated from the system. Therefore, CaO is commonly used as a desiccant or drying agent in various applications where the removal of water vapors is necessary.

The slag is formed by gangue particles. Gangue refers to the unwanted minerals or impurities present in the ore. During the smelting process, when the ore is heated at high temperatures, the gangue particles combine with fluxes (substances that facilitate the removal of impurities) to form slag. Slag is a byproduct of the smelting process and is usually a mixture of various compounds, including oxides and silicates of the gangue minerals. It is separated from the molten metal and discarded. Therefore, the correct answer is gangue particles.

Froth flotation method is used to increase the concentration of minerals. Chalcophyrite is a copper iron sulfide mineral, and froth flotation can be used to separate and concentrate copper sulfide minerals from gangue minerals. This method involves adding certain chemicals to the ore slurry, which creates a frothy mixture. The hydrophobic mineral particles attach to the air bubbles in the froth and rise to the surface, while the hydrophilic gangue minerals sink to the bottom. Therefore, froth flotation can be used to increase the concentration of minerals in chalcophyrite ore.

Liquation is a method based on the principle of difference in melting point of the metal and the impurities. In this process, the impurities with lower melting points are melted and separated from the metal with a higher melting point. This technique is commonly used for purifying metals like tin and lead, where the impurities have lower melting points than the metal itself. Liquation takes advantage of the temperature difference to effectively separate the impurities from the metal.

Magnesium (Mg) cannot be obtained by electrolysis of its aqueous solution because it is a highly reactive metal. When magnesium is placed in water, it reacts vigorously to form magnesium hydroxide and hydrogen gas. Therefore, electrolysis of its aqueous solution would not be possible as the metal would react before any electrolysis could take place.

The refining process is used in all the options mentioned above. This implies that the refining process is applicable in multiple scenarios and industries. It is a common method used to purify and improve the quality of various substances, such as metals, petroleum, and chemicals. The refining process involves removing impurities and unwanted elements to obtain a more refined and desirable end product.

When the temperature is greater than ΔH / ΔS, Mg can reduce SiO2 to Si. This is because the reaction is spontaneous at higher temperatures, where the increase in entropy (ΔS) outweighs the increase in enthalpy (ΔH). In other words, the increase in disorder of the system (ΔS) at higher temperatures allows the reaction to proceed, even though it requires an input of energy (ΔH).

Highly electropositive metals cannot be extracted by carbon reduction process because they do not react with carbon. This means that carbon cannot effectively reduce the metal oxide to its elemental form. Instead, these metals combine with carbon to form carbides, which are not desirable for extraction purposes. Therefore, alternative methods such as electrolysis or other reducing agents need to be employed to extract highly electropositive metals.

Arc furnaces can be used to achieve temperatures above 3000 degrees Celsius. These furnaces use an electric arc to generate heat, which can reach extremely high temperatures. The arc is created between two electrodes and the heat generated can melt metals and other materials. This makes arc furnaces suitable for various industrial processes, such as steelmaking and metal refining, where high temperatures are required.