氢氧化钠在空气中容易潮解,现在实验室中只有片状的氢氧化钠,但只需极微量如29 mg,故不便称量,请问如何把片状氢氧化钠简单的制成粉末状的氢氧化钠?而又不会被潮解引起称量不准确。
It's very easy to make sodium hydroxide into flake powder in the laboratory, but it's very inconvenient to weigh it in the air? And will not be deliquescence caused by inaccurate weighing.
氢氧化钠与氢氧化钠在普通实验室条件下是必然要潮解的,粉碎的状态下潮解更快,不可能准确称量。所以如果只是为了在普通条件下准确称量而想要粉碎片状氢氧化钠的话,就不用考虑了。那么如何准确得到一定量的氢氧化钠呢?
Sodium hydroxide and sodium hydroxide must be deliquesced under ordinary laboratory conditions, and the deliquescence is faster in the crushing state, so it is impossible to weigh accurately. So if you want to crush Flake sodium hydroxide just for the sake of accurate weighing under ordinary conditions, you don't need to consider it. So how to get a certain amount of sodium hydroxide accurately?
方法 1 在干燥气氛下操作,简单的就是在惰性气体保护下的手套箱或者手套袋里称量;
Method 1 was operated in a dry atmosphere, which was simply weighed in a glove box or glove bag under the protection of inert gas;
方法 2 考虑到氢氧化钠一般在溶液中使用,那么可以称取大致的量,溶解于相应的溶剂中,然后用滴定的方法确定真实浓度,滴定的具体流程需要根据溶剂的种类确定,相关信息网上有大量可以获取,另外,注意密封容器以保护溶液不被空气中的二氧化碳所破坏;
Method 2 considering that sodium hydroxide is usually used in solution, the approximate amount can be weighed and dissolved in the corresponding solvent, and then the true concentration can be determined by titration. The specific process of titration needs to be determined according to the type of solvent. There are a lot of relevant information available on the Internet. In addition, pay attention to sealing the container to protect the solution from being damaged by carbon dioxide in the air;
如果你足够大条地觉得10%以内的误差可以接受(俺大条地赶脚其实一般都可以啦),那就弄个spatula捣捣碎(注意不要吸入氢氧化钠粉末哦,很呛人的)再快速称量吧。
If you are big enough to think that the error within 10% is acceptable (in fact, it's OK for me to make a large strip), then mash it with spatula (pay attention not to inhale sodium hydroxide powder, which is very irritating) and then weigh it quickly.