SrB4O7·3．5H2O的合成、表征与热化学研究

合成了一种新型碱土金属硼酸盐SrB4O7·3．5H2O,并对它进行了化学分析、红外光谱（IR）、X射线衍射（XRD）及热分析（TC—DTA）等一系列物相鉴定与表征。通过设计热力学循环,利用微热量计测定了SrB4O7·3．5H2O溶解于约1mol·L^-1 HCl水溶液中的摩尔溶解焓,再结合H3BO,在HCl（aq）的摩尔溶解焓,Sr（OH）2·8H2O（s）溶解于[HCl（aq）＋H3BO3（aq）]的摩尔溶解焓,以及H2O（1）、Sr（OH）2·8H2O（s）与H3BO3（s）的标准摩尔生成焓,得到了SrB4O7·3．5H2O的标准摩尔生成焓为-（4435．15±3．30）kJ·mol^-1。     

抗坏血酸锌的制备及标准生成焓测定

合成了一种新的补锌剂抗坏血酸锌,通过元素分析、红外光谱、热重、电导和化学分析确定了配合物的组成。用新型的具有恒定温度环境的反应热量计,在298·2K条件下分别测定了ZnO(s) C6H8O6(s)配位反应中反应物和生成物在2mol/L HCl溶液中的溶解焓,设计了一个新的热化学循环,得到固相配位反应焓。进而计算出配合物Zn(C6H7O6)2·4H2O(s)的标准生成焓:ΔfHm[Zn(C6H7O6)2·4H2O,s]=-3528·9±0·5kJ/mol。     

VOSO_4·2.76H_2O(s)在水和硫酸水溶液中的溶解焓

在298.15K下利用具有恒温环境的溶解-反应热量计,测定了VOSO4·2.76H2O(s)在水和0.5mol·kg-1硫酸水溶液中的摩尔溶解焓.在硫酸水溶液中VOSO4·2.76H2O(s)摩尔溶解焓的负值比在纯水中要小很多,这说明VOSO4在硫酸水溶液中具有较高的能量状态.借助VOSO4水溶液的离子缔合平衡和硫酸的二级解离平衡,改进了Archer方法,并用这种改进的方法分别估算了VOSO4·2.76H2O(s)在水中的标准摩尔溶解焓△sHm=-29.18kJ·mol-1,以及在0.5mol·kg-1硫酸水溶液中的标准摩尔溶解焓△sHm=-25.79kJ·mol-1.根据离子缔合平衡和硫酸二级解离平衡的计算结果,硫酸根离子浓度受到硫酸二级解离平衡控制,使部分[VOSO4]0离子对解离,致使硫酸氧钒-硫酸水溶液中的自由氧钒离子(VO2+)增加.     

5-氨基间苯二甲酸钠和5-羟基间苯二甲酸钠的热力学性质

在水溶液中合成了5-氨基间苯二甲酸钠(1)和5-羟基间苯二甲酸钠(2)固态样品,元素分析和TG-DTG确定其组成符合C8H5O4NNa2·H2O(1)和C8H4O5Na2·H2O(2).用精密自动绝热热量计测定了它们在78～400K温区的低温热容,将实验值用最小二乘法拟合,得到热容随温度变化的多项式方程,用此方程进行数值积分,得到该温区内每隔5K的舒平热容值和各种热力学函数值.用RD496-2000型微热量计测定了样品在298.15K时的标准摩尔溶解焓分别为ΔsolHmθ(1,s)=-44.552±0.164kJmol-1和θΔsolHm(2,s)=-36.055±0.154kJmol-1,计算了其水合阴离子标准摩尔生成焓分别为θΔfHm(C8H5O4N2-,aq)=-684.56±1.67kJmol-1和ΔfHmθ(C8H4O52-,aq)=-1263.43±2.13kJmol-1.用RBC-II型精密转动弹热量计测定了样品的恒容燃烧热分别为ΔcU(1,s)=-13382.14±5.28Jg-1和ΔcU(2,s)=-10339.15±4.15Jg-1,计算了它们的标准摩尔燃烧焓和标准摩尔生成焓分别为ΔcHmθ(1,s)=-3252.90±1.28kJmol-1和θΔcHm(2,s)=-2522.64±1.01kJmol-1,ΔfHmθ(1,s)=-1406.46±1.66kJmol-1,θΔfHm(2,s)=-1993.79±1.46kJmol-1.     

配合物[Sm(C7H5O3)2(C4H6NO2S)]·2H2O的热化学研究

将六水氯化钐,水杨酸与硫代脯氨酸3种物质一起反应,制得了一种新的稀土三元固体配合物[Sm(C7H5O3)2(C4H6NO2S)].2H2O(s)。通过红外光谱、热重差热分析、元素分析等手段确定了其结构与组成。在常压、298.15 K下,分别测定了六水氯化钐、水杨酸、硫代脯氨酸和该配合物在混合溶剂(二甲亚砜∶乙醇∶3 mol.L-1HCl=1∶1∶1)中的溶解焓,并根据热化学原理得出了298.15 K时配合物[Sm(C7H5O3)2(C4H6NO2S)].2H2O(s)的标准摩尔生成焓ΔfHmΘ=(-2913.73±3.10)kJ.mol-1。     

铈和硫代脯氨酸、水杨酸三元配合物的热化学性质

用七水合氯化铈与硫代脯氨酸(C4H7NO2S)和水杨酸(C7H6O3)合成了三元固体配合物[Ce(C7H5O3)2(C4H6NO2S)]·2H2O。根据盖斯定律设计一个热化学循环,用恒温环境的溶解―反应量热法研究得到合成反应的标准反应焓为263.12±0.95 kJ/mol,进而算出配合物298.15 K时的标准摩尔生成焓为-2785.7±3.2 kJ/mol。     

2006年全国高中学生化学竞赛理论试题参考答案

第1题1-1.A:Na2WO4;B:H2WO4或WO3·H2O;C:WO3⑴4FeWO4(s)+8NaOH(l)+O2(g)4Na2WO4(l)+2Fe2O3(s)+4H2O(g)2MnWO4(s)+4NaOH(l)+O2(g)2Na2WO4(l)+2MnO2(s)+2H2O(g)(产物写成Mn2O3或Mn3O4也可)⑵Na2WO4(aq)+2HCl(aq)H2WO4(s)+2NaCl(aq)⑶H2WO4(s)WO3(s)+H2O(g)1-2.[1]2WO3(s)+3C(石墨)2W(s)+3CO2(g)[2]反应在298.15K时的标准焓变、标准熵变和标准自由能变化分别为:ΔH=ΣυΔfH m=[2×0+3×(-393.51)-2×(-842.87)-3×0]kJ/mol=505.21 kJ/molΔS=ΣυS=[2×32.64+3×213.64-2×75.90-3×5.74]J·mol-1·K-1=537.…     

烟酸锰配合物[Mn(C_6H_4NO_2)_2]·2H_2O(s)的合成、生成焓及其对粟酒裂殖酵母细胞生长代谢的微量热法研究

合成了一种新的烟酸锰配合物,并通过红外光谱﹑热重差热分析﹑元素分析﹑化学分析等手段确定其结构与组成.应用溶解量热法,分别测定了四水氯化锰、烟酸和烟酸锰在常压,298.15 K,混合溶剂(VDMSO∶VEtOH∶V2 mol/L HCl=1∶1∶1)中的溶解焓,△s Hm[MnCl2·4H2O(s),298.15 K]=-(13.596±0.170)kJ·mol-1,△s Hm[2C6H5NO2(s),298.15 K]=(42.780±0.090)kJ·mol-1以及△s Hm[[Mn(C6H4NO2)2]·2H2O,298.15 K]=(15.936±0.070)kJ·mol-1.根据热化学原理求出了反应MnCl2·4H2O(s)+2C6H5NO2(s)=[Mn(C6H4NO2)2]·2H2O(s)+2HCl(g)+2H2O(l).在298.15 K时标准摩尔反应焓△r Hm(1)=(66.42±0.88)kJ·mol-1和配合物[Mn(C6H4NO2)2]·2H2O(s)的标准摩尔生成焓△f Hm[[Mn(C6H4-NO2)2]·2H2O(s),298.15 K]=-(1554.8±2.0)kJ·mol-1.应用TAM air热导式等温微量量热仪测定了烟酸锰配合物[Mn(C6H4NO2)2]·2H2O在301.15 K时对粟酒裂殖酵母细胞生长代谢的产热曲线,计算得到了粟酒裂殖酵母细胞生长速率常数k,最大放热功率时间tp以及总放热量Qtotal等热化学参数.实验结果表明,随着烟酸锰配合物浓度的增加,粟酒裂殖酵母细胞生长代谢速率常数k和总放热量Qtotal减少,即烟酸锰对粟酒裂殖酵母细胞有抑制作用.     

新型三元配合物[RE(C_7H_5O_3)_2(C_6H_4NO_2)·H_2O](RE=La,Ce,Nd)的合成、光谱特性和热化学性质

采用均匀沉淀法,在20%的乙醇水溶液中,用水杨酸、维生素B3与稀土硝酸盐合成了一类新的稀土三元配合物.通过元素分析、化学分析、摩尔电导、红外光谱、紫外光谱、热重-微分热重分析等手段对配合物的结构和性质进行表征,确定了它们的组成通式为[RE(C7H5O3)2(C6H4NO2)·H2O](RE=La,Ce,Nd).维生素B3吡啶环上的N原子和水杨酸的酚羟基均未参与配位,两种配体均是脱质子后以羧酸根与RE3+离子配位,且成键以离子性为主,兼有部分共价性.在298.15 K,用精密的溶解-反应热量计分别测量了配位反应相关各物质的溶解焓,根据盖斯(Hess)定律求得合成反应的标准摩尔反应焓r mHФ分别为:(180.61±0.72)、(187.25±0.68)和(185.61±0.26)kJ/mol.进而求出配合物的标准摩尔生成焓为:f mHФ[La(C7H5O3)2(C6H4NO2)·H2O(s),298.15 K]=-(2493.9±2.9)、f mHФ[Ce(C7H5O3)2(C6H4NO2)·H2O(s),298.15 K]=-(2441.0±2.8)和f mHФ[Nd(C7H5O3)2(C6H4NO2)·H2O(s),298.15 K]=-(2463.1±2.9)kJ/mol.     

量热法对醋酸铜与缬氨酸固相反应的热化学研究

用具有恒温环境的反应热量计，分别测定L－Val(s)、Cu(OAc)2H2O(s）和trans-Cu(L-Val)2(s)、HOAc(1)、H2O(1)在4mol/L HCl溶液中的溶解焓，根据设计的一个热化学循环，可计算出该固相配位反应的反应焓△tHm^φ（298.15K)=20.601kJ/mol，并计算出配合物trans-Cu(L-Val)2(s)的标准生成焓，推荐其值为：△fHm^φ（298.15K)=－1151.31kJ/mol。     

High-precision measurements of 17O/16O and 18O/16O of O2 and O2/Ar ratio in air

A method for high-precision and high-accuracy mass spectrometric measurements of the ratios among the three oxygen isotopes, and of the O(2)/Ar ratio, is presented. It involves separation of the O(2)-Ar mixture from air and includes a fully automated system that ensures highly reliable sample processing. Repeated measurements of atmospheric oxygen yield the repeatability (+/-SE x t, standard error of the mean (n = 12) multiplied by Student's t-factor for a 95% confidence limit) of 0.004, 0.003 and 0.2 per thousand for delta(18)O, delta(17)O and delta O(2)/Ar, respectively.     

High precision measurements of 17O/16O and 18O/16O ratios in H2O

We have optimized the method of water fluorination using the solid reagent CoF3 to produce O2. This allows isotope ratio measurements by dual-inlet mass spectrometry with very high precision of 0.01 to 0.03/1000 for both delta17O and delta18O. Using this method, delta17O and delta18O of atmospheric O2 were determined as 12.08 and 23.88/1000 vs. VSMOW, respectively. Likewise, delta17O and delta18O of GISP were -13.12 and -24.73/1000, and for SLAP they were -29.48 and -55.11/1000 vs. VSMOW, respectively. Analysis of these data in a ln(delta17O + 1) vs. ln(delta18O + 1) plot yields a line with a regression coefficient (lambda) of 0.5279 +/- 0.0001 (R2 = 0.999999). We also determined the fractionation factors 17alpha and 18alpha in liquid-vapor equilibrium, and found that the ratio ln 17alpha/ln 18alpha is constant (0.529 +/- 0.001) over the temperature range 11.4 to 41.5 degrees C.     

Ni(Ⅱ)与Hbbimp配合物的合成、表征及晶体结构

A new complex with binuclear nickel(Ⅱ) complex [Ni₂(bbimp)(CH₃CH₂OH)₂Cl₂]Cl·4H₂O (bbimp=2，6-bis[bis(2-benzimidazolylmethyl)]aminomethyl-4-methylpheno)(o)had been synthesized and characterized by ele-mentary analysis， IR and UV. The molecular structure of the title complex was determined by X-ray single crystal diffraction method. The crystal is monoclinic， space group P2₁/n with a=20.803(2)?， b=30.708(3)?， c=20.959(2)?， β=105.776(2)°， Z=8， V=12885(2)?³， D_x=1.132Mg·m^-3， μ=0.755mm^-1， F(000)=4592， R₁=0.1267， S=1.376. It was showed that the nickel(Ⅱ) cation is the central ion of a distorted octahedral coordination with two N belonging to benzimidazole， a bridging phenolate O， a N of tertiary amine， a Cl anion， and an O of an ethanol molecule. Two nickel(Ⅱ) cations in a molecular structure had the same coordinated environment. CCDC： 197601.     

Electrooptic response of smectic O and smectic O

We present the results of our investigations on the electrooptic properties of the smectic O and O* phases of m7tac (1-methylheptyl terephthalylidene-bis-4-aminocinnamate). At low voltages, we observed striking electrochromic effects and, in O* at high voltages, a field induced phase transition. Freely suspended thick films of m7tac in the O and O* phases are weakly biaxial. A framework is proposed to account for our observations.     

O,O,S-三甲基硫赶磷酸酯在甲胺磷中毒检验中的应用

利用气相色诤质谱(GC-MS)分析了甲胺磷中毒者的检材(血，胃内容物)，均检出了O，O，S-三甲基硫赶磷酸酯，确未检出过甲胺磷。研究了这一现象的原因和确定了O，O，S-三甲基硫赶磷酸酯(O，O，S-TMTP)可作为甲胺磷中毒的佐证物。     

Laser Raman studies on compounds 7.O4O.7 and 7.O5O.7

Laser Raman studies on two compounds of the α,ω-bis(4-alkylanilinebenzylidene -4′-oxy)alkane series were carried out in the spectral regions 1140–1220 and 1550–1650 cm^-1 as a function of temperature. Compounds 7.O4O.7 and 7.O5O.7, exhibit SmA and SmF phases. The structural differences between these liquid crystal dimers, having either an odd or an even number of carbon atoms in the spacer, are remarkably existent in the room temperature Raman spectra. The results are rationalized on the basis of the tendency of these compounds to exhibit bent shapes, and how this manifests in the odd-even effect at the molecular level assuming a semi-rigid core region of the dimeric molecule. It is found that the behaviour of the odd spacer dimer (7.O5O.7) agrees with the molecular model, whereas the even spacer dimer (7.O4O.7) behaves in a similar fashion to monomeric compounds such as the nO.m. compounds. In both cases, dynamic changes around the C=N bond have a profound effect both on the molecular shape in the different phases and on phase behaviour.