30 pts.
1.
CME 203, Fall 2015
Exam II
(Please show your work and start each problem on a new sheet of paper)
Seawater is to be desalinized by reverse osmosis using the scheme indicated below. Use
the flow rates and mass fractions given on the figure to determine:
a) The mass rate of brine waste removal (B)
b) The mass rate of desalinized water (called potable water) production (D)
c) The brine recycle ratio
Brine Recycle
1000 lb./hr Seawater
3.1% salt
4.0% salt
Reverse
Brine waste (B)
5.25% salt
Osmosis
$\frac{M}{2}$
Desalinized water (D)
500 Parts Per Million (PPM) salt
2.
On planet Diabus, wonder medicine Justinium (J, MW = 122 g/gmole) is obtained by
reacting dangerous Kryptonite ($J_2M_3$, MW = 320 g/gmole) with Alainium (A, MW = 56
g/gmole) according to the following reaction:
$J_2M_3 + 3 A \longrightarrow 2J + 3AM$
If 6000 g of Kryptonite and 2500 g of Alainium are placed in the reactor to produce 2000 g
of Justinium, Find the following:
a. The Limiting Reactant
b. Percent Excess
c. Fractional Conversion of Kryptonite to Justinium
d. Percent Yield
