silicon wafer facility uses a mixture of water and sulfur hexafluoride as an etc
ID: 1858308 • Letter: S
Question
silicon wafer facility uses a mixture of water and sulfur hexafluoride as an etchant in their process. water at 10c (10.mol/min) is injected into a flow of liquid SF6 at 30c and the combined stream, whcih contains 90.mol%water, is pre,heated to 90c at 1 atm. notr that this process requires heating two streams to produce a combined stream at a higher temperature.
1) draw a flow chat for this process
2)calculate enthalapies and the specific heat of liquid SF6 is 205 J/mol.C
SF6 >> ( nin=?? nout= ?? Hout= ?? ) Hin=0
water>> ( nout= ?? Hout= ?? ) Hin=0 nin=10
3)calculate the rate of heat transfer required in KW
Explanation / Answer
Hydration of ytterbium (III) halide/hydroxide ions produced by electrospray ionization was studied in a quadrupole ion trap mass spectrometer and by density functional theory (DFT). Gas-phase YbX{sub 2}{sup +} and YbX(OH){sup +} (X = OH, Cl, Br, or I) were found to coordinate from one to four water molecules, depending on the ion residence time in the trap. From the time dependence of the hydration steps, relative reaction rates were obtained. It was determined that the second hydration was faster than both the first and third hydrations, and the fourth hydration was the slowest; this ordering reflects a combination of insufficient degrees of freedom for cooling the hot monohydrate ion and decreasing binding energies with increasing hydration number. Hydration energetics and hydrate structures were computed using two approaches of DFT. The relativistic scalar ZORA approach was used with the PBE functional and all-electron TZ2P basis sets; the B3LYP functional was used with the Stuttgart relativistic small-core ANO/ECP basis sets. The parallel experimental and computational results illuminate fundamental aspects of hydration of f-element ion complexes. The experimental observations - kinetics and extent of hydration - are discussed in relationship to the computed structures and energetics of the hydrates. The absence of pentahydrates is in accord with the DFT results, which indicate that the lowest energy structures have the fifth water molecule in the second shell.
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