In making computer chips, a 4.00-kg cylindrical ingot ofultrapure n-type doped silicon that is 5.20 inches in diameter issliced into wafers 1.12X10⁻⁴m thick.(a) Assuming no waste, how many wafers can be made?(b) What is the mass of a wafer (dof Si =2.34 g/cm³; Vof acylinder =πr²h)?(c) A key step in making p-n junctions for the chip is chemicalremoval of the oxide layer on the wafer through treatment withgaseous HF. Write a balanced equation for this reaction.(d) If 0.750% of the Si atoms are removed during the treatmentin part (c), how many moles of HF are required per wafer, as-suming 100% reaction yield?
Thermochemistry
Thermochemistry can be considered as a branch of thermodynamics that deals with the connections between warmth, work, and various types of energy, formed because of different synthetic and actual cycles. Thermochemistry describes the energy changes that occur as a result of reactions or chemical changes in a substance.
Exergonic Reaction
The term exergonic is derived from the Greek word in which ‘ergon’ means work and exergonic means ‘work outside’. Exergonic reactions releases work energy. Exergonic reactions are different from exothermic reactions, the one that releases only heat energy during the course of the reaction. So, exothermic reaction is one type of exergonic reaction. Exergonic reaction releases work energy in different forms like heat, light or sound. For example, a glow stick releases light making that an exergonic reaction and not an exothermic reaction since no heat is released. Even endothermic reactions at very high temperature are exergonic.
In making computer chips, a 4.00-kg cylindrical ingot ofultrapure n-type doped silicon that is 5.20 inches in diameter issliced into wafers 1.12X10⁻⁴m thick.(a) Assuming no waste, how many wafers can be made?(b) What is the mass of a wafer (dof Si =2.34 g/cm³; Vof acylinder =πr²h)?(c) A key step in making p-n junctions for the chip is chemicalremoval of the oxide layer on the wafer through treatment withgaseous HF. Write a balanced equation for this reaction.(d) If 0.750% of the Si atoms are removed during the treatmentin part (c), how many moles of HF are required per wafer, as-suming 100% reaction yield?
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