【单选题】在沉淀形成过程中,与待测离子半径相近的杂质离子常与待测离子一道与构晶离子形成
【单选题】某食品卫生检验所从一批变质花生仁中,分离出一类化合物,其结构均为二呋喃香豆素衍生物,不溶于水,在紫外线照射下能产生荧光,该化合物可能是
【单选题】Which of the following is NOT true?
A.
When a person tries to help others, he must be clear that there is a real emergency.
B.
When a person tries to help others, he should know whether they are worth his help.
C.
A person must take the full responsibility for the safety of those in emergencies if he wants to help.
D.
A person with a heart attack needs help.
【单选题】关于加巴喷丁,下列选项错误的是
A.
结构上属于GABA衍生物,可转化为GABA发挥作用
D.
与抗病毒药合用可减少急性带状疱疹后遗神经痛的危险
【单选题】在沉淀形成过程中,与待测离子半径相近的杂质离子常与待测离子一道与构晶离子形成
【简答题】某仓储公司税后利润的时间序列数据如表8-21所示。 t 1 2 3 4 5 6 7 8 利润 2.68 2.93 3.30 2.71 4.30 3.24 2.04 1)用加权平均数法给出F8的预测值。设权数分别为1.00、1.32、 1.52、 1.75、 2.01、2.31、2.66。 2)用加权移动平均法计算F5、F6、 F7、F8的预测值,设n=4, 权数顺序为1.00、1.30、1.69、...
【单选题】在沉淀形成过程中,与待测离子半径相近的杂质离子常与待测离子一道与构晶离子形成
【单选题】Which of the following is not tree?
A.
When a person tries to help others, he must be clear that there is a real emergency.
B.
When a person tries to help others, he should know whether they are worth his help.
C.
A person must take the full responsibility for the safety of those in emergencies if he wants to help.
D.
A person with a heart attack needs the most.
【单选题】萨罗(Salo1)是一种消毒剂,属于芳香族含氧衍生物,其分子模型如下图所示(图中球与球之间的连线代表化学键,如单键、双键等)。则下列说法不正确的是:
B.
1mol萨罗与浓溴水反应,需要消耗3mol Br 2
C.
1mol萨罗发生水解,需要消耗3mol NaOH
D.
萨罗经水解、分离、提纯可得到纯净的苯酚和水杨酸(邻羟基苯甲酸)