课程名称︰分析化学丁
课程性质︰必修
课程教师︰林万寅
开课学院：生农学院
开课系所︰园艺系
考试日期（年月日）︰20131107
考试时限（分钟）：110分钟
是否需发放奖励金：是
（如未明确表示，则不予发放）
试题 :
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%
<第一题出错了,整题送分>
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.