Answer:
The traditional electrolyte for aluminium electrolysis is based on molten cryolite (Na3AlF6), acting as solvent for the raw material, alumina (Al2O3).Metals are found in ores combined with other elements. Electrolysis can be used to extract a more reactive metal from the ore.
Aluminum can and is used as both anodes and cathodes in electrochemical cells, but there are some peculiarities to using it as an anode in aqueous solutions. As you note, aluminum forms a passivating oxide layer quite readily, even by exposure to atmosphere. In an aqueous solution, if the potential is high enough, OH− and O2− are generated at the anode, which can then react with the aluminum to produce aluminum oxide. Al^3+ can also be generated directly. The electric field will draw the anions through the growing aluminum oxide layer towards the aluminum surface and the Al^3+ towards the solution, making the oxide layer grow both away from the electrode surface and into the surface of the electrode. In this way, coatings thicker than the normal passivation in air can be produced. However, aluminum oxide is a good electrical insulator, thus if a dense non-porous layer is grown, it will become impossible to pass current through it and growth will stop, leaving a relatively thin oxide layer (this is how the dielectric layers in electrolytic capacitors are made). This is the normal behaviour in aqueous solutions at near-neutral pH (5–7).
However, if a thick aluminum oxide layer is desired (e.g. to produce coatings on aluminum parts for dying or durability), maintaining porosity is necessary to avoid completely blocking access to the surface. One technique that is commonly used is using a low pH solution, which tends to redissolve some of the oxide and neutralize some of the formed OH−, leaving pores in the oxide layer through which the ions can travel and continue to react. These pores also give a good structure to retain dyes or lubricants, but generally need to be sealed after to protect against corrosion.
C. Magma from venus mantle erupted as lava.
Explanation:
A volcano is a land form which results from the eruption of molten rocks (lava) on the surface. Volcanic rocks are a special type of igneous rock that forms when molten rock cools and solidifies on the surface.
For a planet like Venus which is presently not active and little to no movement occurs within the plates, the volcanisim must have occurred when the planet was relatively young and it must have been millions of years ago.
It is widely believed that Venus was geologically active in times past. Mantle generated lava must have solidified on the surface in times past to have formed the volcano.
Evaluating other options:
Impact of space objects on Venus would lead to the formation of a crater which is a depression on the surface. The rock would be mostly metamorphic.
If water was ever present in Venus, they would have produced sedimentary rocks instead. The erosive power of water is not high enough to cut through the crust. Also, water would not aid the formation of volcanoes.
Heat is not enough to from volcanoes. Other factors are also in play.
Answer:
breathing
Explanation:
Your welcome lol
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<span> endothermic is the answer
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Answer:
4.9 × 10²³ molecules
Explanation:
Given data:
Number of molecules = ?
Number of moles of oxygen = 0.815 mol
Solution:
The given problem will solve by using Avogadro number.
It is the number of atoms , ions and molecules in one gram atom of element, one gram molecules of compound and one gram ions of a substance.
The number 6.022 × 10²³ is called Avogadro number.
1 mole = 6.022 × 10²³ molecules
0.815 mol × 6.022 × 10²³ molecules / 1 mol
4.9 × 10²³ molecules
