課程名稱︰質能平衡 Elementary principles of chemical process
課程性質︰選
課程教師︰蔡偉博
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰4/12/2011
考試時限（分鐘）：120
是否需發放獎勵金：yes
試題 :
滿分110
1. (15 points) The density of a fluid is given by empirical equation
d=(A+BT)*e^(CP) , d= density in g/cm^3, T= temperature in degree C,
P = pressure in atm
(a) The equation is dimensionally consistent, units of A,B,C=? (6 points)
(b) In the unit above, A=1.096,B=0.00086,C=0.0000953, find A,B,C if
d is expressed in lb/ft^3, T in degree R, P in lbf/in^2 (9 points)
2. (20 points) A water solution contains 60% Na2S2O2 together with 1% soluble
impurity. Upon cooling to 10 degree C, Na2S2O2。5H2O crystallizes out. The
solubility of this hydrate is 1.4 Na2S2O2 lb/lb free water. The crystals
removed carry as adhering solution 0.06 lb solution/lb crystals. When dried to
remove the remaining water (but not the water of hydration), the final dry
Na2S2O2。5H2O crystals must not contain more than 0.1% impurity. To meet this
specification, the original solution, before cooling, if futher diluted with
water. On the basis of 100 lb of original solution, calculate
(a) The amount of water added before cooling
(b) The percentagerecovery of the Na2S2O2 in the dried hydrated crystals.
(10 points each)
3. (15 points) The emissive power of a blackbody depends on the fuurth power
of the temperature and is given by
W=AT^4, where W= emission power in Btu/(ft^2)(hr)
A= Stefan-Boltzman constant,0.171*10^(-8) Btu/(ft^2)(hr)(degree R)
T= temperature in degree R
What is the value of A in the units J/(m^2)(s)(K^4)?
To be continued......
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作者: lukqwertyuio (縱使相逢應不識) 看板: NTU-Exam
標題: [試題] 99下 蔡偉博 質能平衡 期中
時間: Tue Apr 12 22:26:24 2011
課程名稱︰質能平衡 Elementary pricinples of chemical process
課程性質︰選
課程教師︰蔡偉博
開課學院：工學院
開課系所︰化工系
考試日期（年月日）︰4/12/2011
考試時限（分鐘）：120
是否需發放獎勵金：yes
試題 :
part 2
4. (15 points) A U-tube differential mercury manometer is connected between
two pipes. One pipe contains carbon terachloride (sp.gr. 1.59) under a pressure
of 10^3 kPa, and the other pipe contains oil (sp.gr. 0.80) under a pressure of
172 kPa, Find the manometer reading h in meters.
Figure:
--------
| CCl4 | ----------------------------------------------- =>a
|- ----|
|| --------
|| | |
|| ---------- =>b ============= Y |
|| "" | |
|| "" --------
++ ---------- =>c ""
++ ""
++ ---------- =>d ++
++ ++
+++++++++++++++++++++++++++
+++++++++++++++++++++++++++
distance between a,b = 2.5m , between b,c=1.5m, and between c,d=h
in Y and "", is the oil, in ++ is the mercury, and in || is gas.
5. (20 points) A liquid mixture contains 60.0 wt% ethanol(E), 5.0 wt% of a
dissolved solute (S), and the balance water. A stream of this mixture is fed to
a continuous distillation column operating at stedy state. Product streams
emerge at the top and the bottom of the column. The column design calls for the
product stream to have equal mass flow rates and for the top stream to contain
90.0 wt% ethanol and no S.
(A) Assume a basis of calculation, draw and fully label a process flowchart, do
the degree of freedom analysis, and verify that all unknown stream flows and
compositions can be calculated.
(B) Calculate (i) the mass fraction of S in the bottom stream and (ii) the
fraction of the ethanol in the feed that leaves in the bottom, product stream.
if the process operations as designed.
6. (25 points) A common method used in manufacturing sodium hypochlorite bleach
is by the reaction:
Cl2+2NaOH ==> NaCl +NaOCl+H2O
Chlorine gas is bubbled through an aqueous solution of sodium hydroxide, after
which the desired product is separated from the sodium chloride. A water-NaOH
solution that contains 1145 lb of pure NaOH is reacted with 851 lb of gaseous
chlorine. The NaOCl formed weights 618 lb.
(a) What was the limiting reactant?
(b) What was the percentage excess of the excess reactand used?
(c) What if the degree of completion of the reaction, expressed as the moles of
NaOCl formed to the moles of NaOCl that would have formed if the
reacted (勘誤:reaction) had gone to completion?
(d) What is the yield of NaOCl per amount of chlorine used (on a weight basis)?
(e) What was the extent of reaction?
Exam ends here.
Appendix: Faters for unit conversions
------------------------------------------------------------------------------
Quality Equivalent values
Mass 1 kg = 1000g = 0.001 metric ton = 2.20462 lbm = 35.27392 oz
1 lbm = 16oz = 5*10^(-4) ton = 453.593 g = 0.453593 kg
Length 1 m = 100 cm = 1000 mm = 10^6 mocrons (um) = 10^10 angstroms (A)
= 39.37 in. = 3.2808 ft = 1.0936 yd = 0.0006214 mile
1 ft = 12 in. = 1/3 yd = 0.3048 m = 30.48 cm
Volume 1 m^3 = 1000 L = 10^6 cm^3 = 10^6 mL
= 35.3145 ft^3 = 220.83 imperial gallons = 264.17 gal
=1056.68 qt
1 ft^3 = 1728 in.^3 = 7.4805 gal = 0.028317 m^3 = 28.317 L
= 28,317 cm^3
Force 1 N = 1 kg*m/s^2 = 10^5 dynes = 10^5 g*cm/s^2 = 0.22481 lbf
1 lbf = 32.174 lbm*ft/s^2 = 4.4482 N =4.4482*10^5 dynes
Pressure 1 atm = 1.01325*10^5 N/m^2 (Pa) = 101.325 kPa = 1.01325 bar
= 1.01325*10^6 dynes/cm^2 = 760 mmHg at 0 degree C(torr)
= 10.333 m H2o at 4 degree C = 14.696 lbf/in^2 (psi)
= 33.9 ft H2O at 4 degree C = 29.92 ft Hg at 0 degree C
Energy 1 J = 1 N*m = 10^7 ergs = 10^7 dynes*cm = 2.778*10^(-7) kWh
= 0.23901 cal = 0.7376 ft-lbf = 9.486*10^(-4) Btu
Power 1 W = 1 J/s = 0.23901 cal/s = 0.7376 ft*lbf/s
= 9.486*10^(-4) Btu/s = 1.341*10^(-3) hp
------------------------------------------------------------------------------
Example: the factor to convert grams to lbm is (2.20462 lbm/1000g)
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