A common commercial process for the production of so-calledElectronic Grade Sili

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    A common commercial process for the production of so-calledElectronic Grade Silicon (EGS) is the Siemens process (see figurebelow). EGS is of ultra-high purity enough to be used forfabrication of microchips. The Siemens process is a chemical vapordeposition (CVD) reactor. In CVD feed gases pass over a heatedsubstrate and decompose to deposit a thin solid film on thesubstrate. In the Siemens process a chamber contains a heatedsilicon rod. An ultra-high purity gas mixture of trichlorosilaneand hydrogen flows over the rod. Pure silicon deposits on the rodas a poly-crystalline solid. (Single crystals of silicon neededfor microchip fabrication are later made by melting the EGS anddrawing a single crystal from the melt.) The CVD reaction isH2(gas) + SiHCl3(gas) ? Si(solid) + 3HCl(gas) The rod initially hasa mass of 1460 g and the mole fraction of hydrogen in the reactorfeed and the exit gas is 0.580 and 0.223 respectively. The feedenters at a rate of 6.22 Kmol/hr. Assuming steady-state what willbe the mass of the rod at the end of 20 mins?

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