【单选题】采用亚硝酸钠法滴定时应控制滴定的速度,正确的是:
A.
将滴定管尖从液面上方一次将大部分亚硝酸钠滴定液在搅拌下迅速加入,接近终点时,继续缓缓滴定至终点
B.
将滴定管尖端插入液面下约2/3处,一次将大部分亚硝酸钠滴定液在搅拌下迅速加入,接近终点时,将滴定管尖端提出液面,用少量水淋洗尖端,继续缓缓滴定至终点
C.
将滴定管尖从液面上方快速加入亚硝酸钠滴定液,边滴边摇,接近终点时,慢慢滴定至终点
D.
将滴定管尖端插入液面下方,一次将2/3的亚硝酸钠滴定液在搅拌下迅速加入,接近终点时,将滴定管尖端提出液面,用少量水淋洗尖端,继续缓缓滴定至终点
【简答题】若集合A中有3个元素,则集合A的子集个数为 ,真子集个数为 。
【判断题】Corporate social responsibility is a form of corporate self-regulation integrated into a business model, and it is also known as corporate citizenship, sustainable responsible business, or corporate s...
【简答题】corporate social responsibility
【单选题】电力网中,当电感元件与电容元件发生串联且感抗等于容抗时,就会发生()谐振现象。
【简答题】More and more corporations are taking an interest in corporate social responsibility (CSR). CSR is made up of three broad layers. The most basic is traditional corporate charity work. Companies typica...
【简答题】集合 A 中有 3个元素,则集合 A 子集个数为
【单选题】Corporate social responsibility:
A.
Is not related to ethics
B.
Refers to the actions of a firm to benefit society beyond the requirements of the law and the direct interests of the firm
C.
Involves the study of or the learning process involved in understanding morality, while ethics involves taking action
D.
Is not based on voluntary actions
【单选题】在电力网中,当电感元件与电容元件发生串联且感抗与容抗相等时,就会发生()谐振现象。
【单选题】采用亚硝酸钠滴定法测定磺胺甲 噁 唑原料药的含量时,滴定时将滴定管尖端插入液面下 2 / 3 处的目的是( )
D.
避免亚硝酸钠在酸性条件下形成的亚硝酸挥发和分解