【判断题】Although straight-A illiteracy affects fewer people than ordinary illiteracy, Degnan still thinks it is worse than the latter type.
【简答题】When I entered Berkeley. I hoped to earn a scholarship. Having been a Straight-A student, I believed I could 36 tough subjects and really learn something. One such course was World Literature given by...
【单选题】下面哪种说法不属于 S N 2 机理( )
A.
双分子反应,反应速率与卤代烷及亲核试剂浓度有关;
B.
反应一步完成,旧键的断裂和新键的生成同时进行;
C.
有活泼中间体正碳离子生成,若反应物中连卤素的碳原子为手性碳原子,则可能发生外消旋化。
【简答题】When I entered Berkeley, I hoped to earn a scholarship. Having been a Straight-A student, I believed I could tough subjects and really learn something. One such course was World Literature given by Pr...
【判断题】S N 2 反应过程中生成活性中间体碳正离子。
【简答题】In geodetic surveys, the shape of the earth is thought of as a spheroid, although in a technical sense, it is not really a spheroid. There fore, distances measured on or near the suce of the earth ...
【多选题】关于开普勒行星运动的公式 =k,以下理解正确的是( )
B.
若地球绕太阳运转轨道的长半轴为R,周期为,月球绕地球运转轨道的长半轴R’ 周期为 T,则 =