【简答题】(三选一)【选修3:物质结构与性质】 硅与金刚砂(SiC)是两种重要的工业产品,它们都可由二氧化硅与碳反应制得。 (1)由SiO 2 生成SiC的化学方程式是_________________。 氮化硅(Si 3 N 4 )也是一种高硬度高沸点的物质,其制备方法是在H 2 的保护下,使SiCl 4 与N 2 反应沉积在石墨表面,形成一层致密的氮化硅层,写出该反应的化学方程式____________...
【简答题】(16分)某药学杂志报道了一种具有明显抗癌活性的药物,其结构如图所示。J是其同分异构体,J的合成路线如下(部分产物已略去): 已知:① CH 2 =CHR 1 + CH 2 =CHR 2 CH 2 =CH 2 + R 1 CH=CHR 2 ② R—CH 2 —CH=CH 2 + Cl 2 R—CHCl—CH=CH 2 + HCl ③ 核磁共振氢谱图显示A分子中不同环境氢原子个数比为3 :1;F是油...
【单选题】She frowned at the business report, an effort to _______ herself before she talked to the employees at the upcoming meeting. A、consist
【简答题】已知A、B、C、D、E、F、G七种元素,G原子核外有四个电子层,其余原子至多只有三个电子层,且原子序数依次递增.A、B、F位于周期表的s区,A原子中电子层数和未成对电子数相同,B和A同族且位于A的下一周期,C元素基态原子中电子占据三种能量不同的原子轨道,且每种轨道中的电子总数相同,E的基态原子核外成对电子数是未成对电子数的3倍,F与E不同周期且F在其周期中的电负性最大,G原子d轨道有7个电子. 请...
【单选题】She frowned at the business report, an effort to ____ herself before she talked to the employees at he upcoming meeting.
【简答题】氧氮杂 是新药研制过程中发现的一类重要活性物质,具有抗惊厥、抗肿瘤、改善脑缺血等性质。下面是某研究小组提出的一种氧氮杂 类化合物H的合成路线: (1)原料A的同分异构体中,含有苯环、且核磁共振氢谱中有4个峰的是 (写出其结构简式)。 (2)反应②的化学方程式是_________________。 (3)③的反应类型是___________。原料D中含有的官能团名称是_________、______...
【单选题】Sometimes she eats a lot and sometimes nothing at all; she just goes from one ________ to the other.
【单选题】Different from retributive justice, corrective justice is adopted in the way according to the ______.
A.
outcome of the sentence
B.
severity of the punishment
C.
type of crime that was proven
D.
the administration of the higher law system
【单选题】She frowned at the business report, an effort to _______ herself before she talked to the employees at the upcoming meeting.
【单选题】A sword is in the Lady of Justice’s hand to indicate _____________
A.
Justice can be swift and final
B.
Justice can be measured
C.
Justice can be impartial to everyone
D.
Justice can be balanced between the supporters and opponents