Practice_Exam1_solutions

# Practice_Exam1_solutions - ECH 3023 Practice Exam...

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ECH 3023 Practice Exam 1-Solutions Fall 2006 Open book, one page of notes.  Show all work.  Box all answers.   1. (20 pts.)   The  Marangoni  number is a dimensionless group defined as: μα β T L Ma = 3 where  is a length,  μ  is the  viscosity  (mass/length-time) of a fluid,  ∆Τ is a temperature difference, and  α is the  thermal diffusivity  (length 2 /time).  What is the dimension of  ? Justify your answer. temp time length mass temp length time length time length mass T L 2 2 3 2 3 ] [ ) / )( / ( ] [ ] [ = - = = 2. (20 pts) Calculate the mass fractions of each species in an equimolar stream of N 2 , CO 2 , and O 2 . ) 32 )( 3 / 1 ( ) 44 )( 3 / 1 ( ) 28 )( 3 / 1 ( ) 28 )( 3 / 1 ( 2 2 2 2 2 2 2 2 2 + + = + + = O O CO CO N N N N N M y M y M y M y x =0.27 2 2 2 2 2 2 2 2 2 O O CO CO N N CO CO CO M y M y M y M y x + + = =0.42 2 2 2 1 N CO O x x x - - = =0.31 1

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ECH 3023 Practice Exam 1-Solutions Fall 2006
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Practice_Exam1_solutions - ECH 3023 Practice Exam...

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