In making computer chips, a 4.00 kg cylindrical ingot of ultrapure n-type doped silicon that is 5.20 inches in diameter is sliced into wafers .00012 m thick.
a)How many wafers can be made assuming no waste?
b) What is the mass of a wafer? (d=2.34g/cm^3; V of a cylinder = pir^2h)
c) A key step in making p-n junctions for the chip is chemical removal of the oxide layer on the wafer through treatment with gaseous HF. Write a balanced equation for this reaction.
d) If .75% of the Si atoms are removed during the treatment in part (c), how many moles of HF are required per wafer assuming 100% reaction yield?