[試題] 102上 林萬寅 分析化學丁 期中考
課程名稱︰分析化學丁
課程性質︰必修
課程教師︰林萬寅
開課學院：生農學院
開課系所︰園藝系
考試日期（年月日）︰20131107
考試時限（分鐘）：110分鐘
是否需發放獎勵金：是
（如未明確表示，則不予發放）
試題 :
1.Knowing that Ksp=2.0*10^-6 for PbBr2, answer the following questions.
(A)Find the solubility in if PbBr2(s) in 0.1M KI aqueous solution. 5%
(B)Recalculate the solibility in (A) if the activity coefficients of Pb+2 and Br
at an ionic strength of 0.10M are 0.36 and 0.75, respectively. 5%
<第一題出錯了,整題送分>
2.Find the pH of a solution containing (4.0±0.2)*10^-2M HA. Ka=(1.0±0.1)*10^
-6 for HA. The final answer must include the uncertainty. 15%
3.Knowing that Ksp=1.6*10^-18 for Ag3Po4, K1=7.0*10^-3, K2=6.0*10^-8, K3=
5.0*10^-13 for H3PO4 and Kw=1.0*10^-14, answer tje following questions.
(A)Write all chemical equations in the aqueous solution of AgPO4(s). 10%
(B)Write the charge balance equation for the solution in (A). 3%
(C)Write the mass balance equation for the solution in (A). 3%
(D)Find the solubility of AgPO4(s) in a solution buffered at pH 6.0. 9%
4.Assume that the activity coefficients, at an ionic strength of 0.10M, for
ions with charges ±1, ±2, and ±3 are 0.80, 0.40 and 0.20, respectively.
Predict whether each of the following equilibria will shift to right or left
or be unchanged when the ionic strength of the solution increases from 0 to
0.10M.Explain briefly.
(A)Fe+3 + SCN- ←→ Fe(SCN)+2 5%
(B)H3AsO3 + I3- + H2O ←→ H3AsO4 + 3I- + 2H+ 5%
5.Analysis of gossypol (棉酚; C30H30O8)in two samples of cotton seed oil gave:
6.58±0.28ppm(N=5) and 6.36±0.20ppm (N=7); the results were expressed as mean
±standard deviation for N measurements. Assume 95% confidence level throughout
this problem. Answer the following questions.
(A)Find the confidence limit for the first result. 5%
(B)Calculate a pooled standard deviation (sp) for the two sets of data. 5%
(C)Do the two samples differ in their gossypol contents?(use sp for the t-test)
5%
(D)If the density of the oil samples is 0.80g/mL. Find the molarity of gossypol
in the fist sample (i.e.,6.58 ppm=?M).(C=12,H=1.0,O=16) 5%
df│ 4 │ 5 │ 6 │ 7 │ 8 │ 9 │ 10 │ 11 │ 12 │
├─┼──┼──┼──┼──┼──┼──┼──┼──┼──┤
t │2.78│2.57│2.45│2.36│2.31│2.26│2.23│2.20│2.18│
6.Water from a 10-mL pipet was drained into a 10.750-g weighing bottle to give
a new mass of 20.860g at 25。C. Find the volume of the pipet corrected for the
buoyancy.The density of air, weight and water at 25。C are 0.0012g/ml, 8.0g/ml
,and 0.997048g/ml,respectively. 5%
7.Define the following terms. 15%
(A)coagulation and peptization.
(B)relative supersaturationand homogeneous precipitation.
(C)occlusion and mix-crystal formation.
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