中 国 科 学 技 术 大 学 04—05学年第一学期期中考试试卷
(供04级3系、19系学生用) 2004.11.7
考试科目: 无机化学 得分:__________ 学生所在系:___________ 姓名:__________ 学号:___________
一、选择题(20分,每小题只有一个正确的答案,1分)
1.下列方程式中,正确的是(p、V各为气体总压、总体积,pi、Vi各为第i组份气体
的分压、分体积) ( ) (A) piVi = nRT (B) piVi = niRT (C) pVi = nRT (D) pVi = niRT
2.根据Pauling的酸强度规则,H3PO4、H4P2O7和HPO3的酸强度顺序为 ( )
(A) H3PO4>H4P2O7>HPO3 (B) HPO3>H4P2O7>H3PO4 (C) H3PO4>HPO3>H4P2O7 (D) HPO3>H3PO>H4P2O7
+
3.下列各物种中,属于N2H5的共轭碱的是 ( )
(A) NH3 (B) N2H4 (C) N2H62+ (D) N2H5OH
4.下列各缓冲对,属于人体中的缓冲对的是 ( )
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(A) H2CO3 ?? HCO3 (B) HCO3 ?? CO32–
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(C) H3PO4 ?? H2PO4 (D) HPO42– ?? PO43–
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5.已知MO(OH)(s) MO+(aq) + OH(aq)的Ksp = 1.0×10–24,则MO(OH)(s)的饱和溶
液的pH为 ( ) (A) 2 (B)12 (C) 7 (D) 0 6.在温度T时的液体的蒸气压为p,液体的蒸发焓可以从下列何种直线中获得 ( )
(A) p对T作图 (B) p对1/T作图 (C) ln p对T作图 (D) ln p对1/T作图
111N2(g) + O2(g) + Cl2(g) NOCl的? fHm 为12.6 kJ ? mol–1,222假设上述气体均为理想气体,则?U为 ( ) (A) 12.6 kJ ? mol–1 (B) 46.3 kJ ? mol–1 (C) 13.8 kJ ? mol–1 (D) 74.22 kJ ? mol–1
8.对于NO(g) + CO(g) 1/2N2(g) + CO2(g)而言,? rHm = –374 kJ ? mol–1,为获得
尽可能大的转化率,应采取的措施为 ( ) (A) 高温、低压 (B) 高温、高压 (C) 低温、低压 (D) 低温、高压
9.在密闭容器中,有A、B两只敞口杯子,A杯中装入1/3纯乙醇,B杯中装入1/3
的稀乙醇,最终的现象是 ( ) 7.在25℃,反应
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(A) A杯空 (B) A、B两杯中有浓度相同的乙醇溶液 (C) B杯空 (D) A、B两杯中有浓度不同的乙醇溶液
10.下列叙述中,正确的是 ( )
(A) 在一定温度下,难溶电解质离子浓度的乘积是一个定值。
(B) 在气相平衡N2 + 3H2 2NH3体系中,维持体系的温度、体积不变,引入
稀有气体,则平衡向右移动。 (C) 升高温度,化学平衡常数变大。
(D) 弹式量热计测得的热量是体系内能的变化。 11.能把HClO4与HNO3的酸度区分开来的溶剂是 ( ) (A) 水 (B) NH3(l) (C) H2NCH2CH2NH2 (D) CH3COOH
12.难溶电解质M2S3(s)的溶解度S o(mol ? dm–3)是其溶度积Ksp的函数,若不考虑水
解,它们的关系式为 ( )
1/5/5(A) S o = K1sp (B) S o = (Ksp /108)
(C) S o = (108Ksp )1/5 (D) S o = (Ksp /128)1/5 13.在Na2HPO4(aq)中,质子平衡式为 ( )
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(A) [ H3O+ ] + [ H2PO4] + 2 [ H3PO4 ] = [ PO43? ] + [ OH]
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(B) [ H3O+ ] = [ H2PO4] + 2 [ HPO42? ] + 3 [ PO43? ] + [ OH]
--
(C) [ Na+ ] + [ H3O+ ] = [ H2PO4] + [ HPO42? ] + [ PO43? ] + [ OH]
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(D) [ Na+ ] + [ H3O+ ] = [ H2PO4] + 2 [ HPO42? ] + 3 [ PO43? ] 14.反应F3B-NF3 + NH3 F3B-NH3 + NF3的反应类型是 ( )
(A) 酸碱加合反应 (B) 酸取代反应 (C) 碱取代反应 (D) 双取代反应 15.在渗流实验中,一定摩尔数的某气体通过小孔渗向真空需要38.4秒钟;在相同条
件下,相同摩尔数的氧气渗流需要18.0秒钟,则未知气体的分子量为 ( ) (A) 145.6 (B) 56.25 (C) 15 (D) 68.27
16.在某温度下,碘和氯仿的饱和蒸气压分别为0.31torr和199.1torr,在I2氯仿饱和溶
液中,I2的摩尔分数为0.0147,则饱和的I2的氯仿溶液上方的蒸气压为 ( ) (A) 196.5torr (B) 196.17torr (C) 196.175torr (D) 199.1torr 17.等物质的量的CO和H2O混合,在高温下反应:CO + H2O CO2 + H2 当CO的转化率为24.37%时,混合气体密度与相同条件下氢气密度之比是 ( )
(A) 46 (B) 11.5 (C) 23 (D) 5.75
18.下列各式中,属于正确的水解反应方程式的是 ( )
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(A) CO32? + 2H2O H2CO3 + 2OH
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(B) CH3COOH + H2O CH3COO + H3O+ (C) NH4+ + 2H2O NH3 ? H2O + H3O+
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(D) HS + H2O S2? + H3O+
19.酸雨是因为过度燃烧煤和石油,产生的硫和氮的氧化物溶于水,生成了硫酸与硝
酸的缘故。对某次酸雨中,一些离子浓度的数据分析如下:cNH?=2.0×10?8mol?dm–3,
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cNa?= 3.0×10mol ? dm,cNO?= 1.0×10mol ? dm,cSO2?= 1.0×10?5mol ? dm–3。
?6
?5
34–3–3
2
此次酸雨的pH值最接近 ( ) (A) 4.30 (B) 4.52 (C) 4.57 (D) 4.77 20.已知Fe2O3(s) + 3CO(g) 2Fe(s) + 3CO2(g) Δ1Hm 3Fe2O3(s) + CO(g) 2Fe3O4(s) + CO2(g) Δ2Hm Fe3O4(s) + CO(g) 3FeO(s) + CO2(g) Δ3Hm FeO(s) + CO(g) Fe(s) + CO2(g) Δ4Hm
上述各反应的反应热之间的关系表达式中,正确的是 ( )
(A) Δ1Hm = Δ2Hm + Δ 3Hm + Δ 4Hm (B) 3Δ1Hm = Δ2Hm + 2Δ3Hm + 6Δ 4Hm
1Δ2Hm + Δ3Hm + Δ 4Hm 3(D) Δ1Hm + Δ 4Hm = Δ 2Hm + Δ 3Hm (C) Δ1Hm =
二、填空题(30分)
1.(5分) 称为第一
类永动机,它 (能或不能)制造出来,因为它违背 定律。证明 。 2.(5分)从装置上来讲,产生渗透压的必要条件是 。渗透压产生的实质是 ,所以在U型管两边浓度不等的溶液中, 溶液的液面高。利用渗透压原理, (能或否)实现海水淡化,其理由是 。 3.在25℃,密闭容器中,反应4HCl(g) + O2(g) 2H2O(g) + 2Cl2(g),首先放入1atm
的HCl(g)和1atm的O2(g),平衡时氧气分压减少了px,则 Kc = Kp× , Kp = , Kx = Kp× 。
Kp和Kc与 有关,Kx与 和 有关,Kc、Kp、Kx在数值上相等的条件是 。反应O3(g) 3/2O2(g)的Δ rGm = –163 kJ?mol–1,计算该反应的Kc, 298K = ,Kp, 298K = 。 4.(5分)N2O4(l)自偶电离的方程式为 ,Cu与N2O4(l)反应的
化学方程式为 。在N2O4(l)中NOCl与CsNO3反应的方程式为 。无论是液态的BrF5还是AsF5都是不良的电解液,但它们的混合物是比这两种纯化合物中任何一种都要好的电导液。说明该现象的方程式是 。在100%的H2SO4,1mol HNO3与2mol H2SO4反应,生成4mol离子的方程式为 。 5.(5分)溶胶(sol-gel)中的分散相的粒径范围在 ,检验溶胶与真溶液
的方法有 。用KI(aq)与AgNO3(aq)来制备AgI的溶胶,当KI过量
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时,AgI溶胶呈 电性;当AgNO3过量时,AgI溶胶呈 电性。这是因为 。
三、(20分)
1.为利用近海天然气矿中的甲烷在工业上生产醋酸或乙醇,可以利用下面两个反应。
(1) 试计算在298K和p 条件下下列两反应的Kp ,并指出哪一个反应可行。
CH4(g) + CO2(g) CH3COOH(g) 2CH4(g) + H2O(g) C2H5OH(g) + 2H2(g) ΔfHm (kJ?mol?1) Sm (J?K?1?mol?1) CH4(g) ?74.81 186.15 CO2(g) ?393.51 213.6 H2(g) - 130.57 H2O(g) ?241.82 188.72 CH3COOH(g) C2H5OH(g) ?431.92 282.84 ?235.3 282.59 (2) 计算0℃时,反应CH4(g) + CO2(g) CH3COO(g)的Kp 2.已知Δ cHm, C6H6(l) = –3268kJ? mol–1,Δ cHm, C6H12(l) = –3920kJ?mol–1,水的Δ vapH m = 40.7 kJ?mol–1,Δ fHm, H2O(g) = –241.82kJ? mol–1,试求苯氢化反应生成环己烷的焓变。
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四、(20分)所谓“酸雨”(Acid rain)是指大气中的SO2和NOx被氧化成SO3和NO2
并分别与水反应生成硫酸和硝酸,使雨水的pH为4.5,最低可达1.7。
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SO2(aq) + H2O(l) HSO3(aq) + H+(aq) Ka1 = 10 –1.92
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HSO3(aq) SO32– (aq) + H+(aq) Ka2 = 10–7.18
1. 在SO2的分压为1atm时,它在每升水中的溶解度为33.9升(25℃时)
(1) 计算被二氧化硫饱和的水中的二氧化硫总浓度(设SO2溶解后水的体积不变) (2) 计算亚硫酸氢根离子的百分含量 (3) 计算该溶液的pH 2. 计算含0.0100 mol ? dm–3亚硫酸钠水溶液中的氢离子浓度
3. 在亚硫酸氢钠水溶液中存在如下的主要平衡,(1) 计算它的平衡常数
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2HSO3(aq) SO2 (aq) + SO32– (aq) +H2O(l)
(2) 若只考虑此平衡,计算0.0100 mol ? dm–3亚硫酸氢钠水溶液中的二氧化硫浓度。 4. 亚硫酸钡在水中的溶解度为0.016g/100mL(MBaSO3 = 217.39),试计算亚硫酸钡的Ksp 5. 亚硫酸银的溶度积为10 –13.87。计算亚硫酸银饱和水溶液中的银离子浓度。 6. 亚硫酸钙的Ksp = 10 –7.17,试求下列反应的平衡常数 Ca2+(aq) + Ag2SO3(s) CaSO3(s) + 2Ag+(aq)
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五、(10分)右图是水的相图。
DCI是 区,II是 区,III是 区,B点是水
的 ,沿着BC线 速率= 速
(II)率,所以 相共存。
(III) 一定量的水放在密闭容器中,该容器连接真空泵。打开真
空泵,水首先表现出 ,然后再 。最后会B(I)出现 。试在相图上画出示意图并文字解释为:
ATemperature
。
Additional Exam (20 points)
1. Each of the questions or incomplete statements below is followed by four suggested
answers or completions. Please give your answer that is best in each case.
(1) Which of the following sets of conditions describes a system undergoing a reversible
change? ( ) ?Ssystem ?Ssurronding ?Stotal
(A) positive zero positive (B) positive negative zero (C) positive positive zero (D) negative zero negative
(2) The statement that heat cannot spontaneously flow from a colder to a hotter body is a
resulf of ( ) (A) the first law of thermodynamics (B) the second law of thermodynamics (C) the third law of thermodynamics (D) Le Chatelier’s principle
(3) Benzene and toluene form nearly ideal solutions. The vapor pressure of pure tolecene
is 22torr at 20℃. For an equimolar mixture of benzene and toluene at 20℃ the vapor pressure of toluene is: ( ) (A) 5.5torr (B) 7.3torr (C) 11torr (D) 22torr
(4) Which equation correctly describes the relationship between Kp and Kc for the
following reaction? Cl2(g) + 3F2(g) 2ClF3(g) ( ) (A) Kp = Kc (B) Kp = Kc (RT) –1 (C) Kp = Kc (RT) –2 (D) Kp = Kc(RT) 2
(5) Which of the following reactions would be expected to involve the largest increase in
entropy ? ( ) (A) H2O(l) H2O(g) (B) H2O(s) H2O(l) (C) H2(l) H2(g) (D) He(l) He(g)
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Pressure(6) The reaction, 3NH4+ + BiN(s) Bi3+ + 4NH3 , occurs in liquid ammonia. In this
reaction the amnonium ion behaves as ( ) (A) an oxidizing agent (B) a reducing agent (C) an acid (D) a base
(7) If the solution is not supersaturated, what is the maxinum Bi3+ concentration that can
be reactant without causing precipitation in a solution containing 0.01mol per liter of S2– ? (The Ksp bismuth sulfide may be taken as 1×10–70) ( ) (A) 1×10–72 mol ? dm–3 (B) 1×10–64 mol ? dm–3 (C) 1×10–34 mol ? dm–3 (D) 1×10–32 mol ? dm–3
(8) Which of the following carbonate species would be present in significant
concentrations in a solution of carbonic acid at pH = 10?(For carbornic acid, Ka1 = 3.5×10–7, Ka2 = 7.0×10–11) ( )
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(A) H2CO3 only (B) H2CO3 and HCO3
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(C) CO32– only (D) HCO3 and CO32– (9) Which of the following statements is true ?(CdS: Ksp = 8×10–27, CuS: Ksp = 6.3×10–36,
Ag2S: Ksp = 6.3×10–50) ( ) (A) CdS is less soluble than CuS
(B) CdS is about 109 times more soluble than CuS (C) Ag2S is less soluble than either CdS or CuS (D) Ag2S is about 10 time more soluble than CuS
(10) For which of the following reactions change roughly equivalent changes in internal
energy and enthalpy ( )
(A) 2H2(g) + O2(g) 2H2O(g)
(B) Pb(NO3)2(s) + 2KI(s) PbI2(s) + 2KNO3(s)
(C) CaCO3(s) + 2HCl(aq) CaCl2(aq) + CO2(g) + H2O(l) (D) NaOH(s) + CO2(g) NaHCO3(g)
2. An organic nitro-compound (RNO2) is electrolytically reduced in aqueous acetate buffer
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solution having total acetate concentration (HOAc + OAc) 0.500M and pH = 5.0. 300mL of the buffered solution containing 0.01M RNO2 was reduced completely. The dissociation constant for acetic acid is 1.75×10–5 at 25℃. The reduction reaction is
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RNO2 + 4H+ + 4e RNHOH + H2O
Calculate the pH of the solution on completion of the reduction of RNO2.
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3. “Green” Chemistry ?? The Use of Supercritical CO2
Recently, reactions in supercritical carbon dioxide (critical temperature Tc= 304.3 K; critical pressure pc = 72.8×105 Pa) have received significant attention. The density of a liquid can be easily tuned near the critical point. Moreover, it can be regarded as a ―green‖ solvent that can replace organic solvents. This solvent has actually been used for caffeine extraction for quite a long time. The fact, however, that carbon dioxide has to be compressed is one of the few disadvantages. Real gases can be described by the van-der-Waals equation (although it is still an approximation): constants for CO2: a = 3.59×105 Pa dm6 mol–2 , b = 0.0427 dm3 mol–1
(1) Calculate the pressures needed to achieve a density of 440 g dm–3 at temperatures of
305 K and 350 K.
(2) The use of carbon dioxide both as a solvent and as a reactant instead of phosgene or
carbon monoxide is another example of supercritical processes. Both the catalytic formation of organic carbonates and formamides have already been described. Write a balanced equation of the formation of dimethyl carbonate by the reaction of
methanol with carbon dioxide. How can dimethyl carbonate form if phosgene is the reactant?
(3) From the point of view of ―green chemistry‖ – why should reactions be carried out in
CO2 instead of using carbon monoxide or phosgene (2 reasons)?
(4) Apart from the compression of carbon dioxide, what is the main obstacle in using CO2
as a reactant in comparison to CO or COCl2 (1 reason) ?
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