【多选题】选择SPE 小柱或滤膜:( )。
A.
首先应根据待测物的理化性质和试样基质, 选择对待测物有较强保留能力的固定相
B.
若待测物带负电荷,可用阴离子交换填料, 反之则用阳离子交换填料
【单选题】Japans Number Five Travel Company by Takako Makino Sapporo - In its October edition, National Travel Magazine rated the Sapporo-based the Narita Travel Company at number five on its list of Top Ten Tr...
A.
It offers more outdoor activities than other travel companies.
B.
It designs trips that participants are likely to remember for a long time.
C.
It is one of the most popular travel companies in the country.
D.
It is more committed to the environment than its competitors.
【简答题】A.House sales company. B.Motor sales company. C.Food sales company. D.Travel agency.
【简答题】A.house sales company. B.motor sales company. C.food sales company. D.travel agency.
【简答题】A.House sales company. B.Motor sales company. C.Food sales company. D.Travel agency.
【简答题】某研究小组以苯甲醛为原料,制备苯甲酸和苯甲醇。反应原理如下 有关物质的部分物理性质如下 实验步骤: (1)在250 mL锥形瓶中,加入9 gKOH和9mL水,配成溶液,冷却至室温。加入10.5 g新蒸馏的苯甲醛,塞紧瓶塞,用力振荡,使之变成糊状物,放置24 h。 ①苯甲醛要求新蒸馏的,否则会使____________(填物质名称)的产量相对减少。 ②用力振荡的目的是_____________。 (...
【单选题】某男性在海边游泳时不慎溺水,被人救起,体检:呼吸急促,肺部可闻及哮鸣音和湿罗音, HR108/min ,偶闻早搏 2 ~ 3/min ,腹部膨隆,四肢厥冷,该患者不应该发生以下哪项问题:
【简答题】现有九种有机物:①甲烷 ②溴乙烷 ③乙炔 ④丙三醇 ⑤ ⑥苯 ⑦甲苯 ⑧乙烯 ⑨乙醇 (1)将序号填入下列相应的空格中: 日常生活中作燃料的是___________(至少写一种);作为制取炸药原料的是________(至少写一种);常温下能与溴水发生加成反应的是_______________;常温下呈液态,能作溴水的萃取剂,也能使酸性高锰酸钾溶液褪色的是____________;互为...