原文由 christe 发表:
问题:
1 Add about 50 ml of water, mix to effect solution, dilute with water to volume, and mix.
加大概50ml水,混合均匀后,用水定容,混匀?
大概: 约...
2 transfer 20.0 ml of this solution to the reaction flask of a suitable fluoride steam distilling apparatus containing 10 lime-glass beads measuring 5 mm in diameter and 70 ml of dilute sulfuric acid(1 in 2). distill, by passing steam through the solution in the reaction flask and applying heat to the flask, collecting the distillate in a 250 ml volumetric flask.
移取20.0ml该溶液到可用于氟蒸馏的反应烧瓶中,烧瓶内装有10粒钙玻璃珠和70ml(1:2)的硫酸.蒸馏,passing steam through the solution in the reaction flask and heat to the flask.馏分收集在250ml容量瓶中.
硫酸:稀释的? 但是dilute不太对
于反应烧瓶中通蒸汽过溶液并加热烧瓶进行蒸馏,收集馏分于...
原文由 christe 发表:
3 change receivers when the flask is filled to volume with distillate, and continue distilling into a 400-ml beaker until an additional 150ml to 200ml of distillate tailing has been collected. mix the solution in the 250ml volumetric flask,
当容量瓶收集到馏分后改用400ml的烧杯做承接器,至收集到150-200ml馏分,混合250ml容量瓶中的馏分.
为什么要分两个容器来接馏分呢?
加入的量是20ml 母液和70ml硫酸,怎么会有150-200ml的馏分收集呢?
是否我哪里理解错了
250 ml 容量瓶收集至刻度后(满)后换成烧杯
一个可能性是因为没有更大的容量瓶(大于400),而预知馏分在400左右。如果直接用烧杯,容易溅出(或者其他原因),因此要先用250ml容量瓶。
因为导入是蒸汽,会不会蒸汽冷却后也进入到了馏分呢?
原文由 christe 发表:
3 change receivers when the flask is filled to volume with distillate, and continue distilling into a 400-ml beaker until an additional 150ml to 200ml of distillate tailing has been collected. mix the solution in the 250ml volumetric flask,
当容量瓶收集到馏分后改用400ml的烧杯做承接器,至收集到150-200ml馏分,混合250ml容量瓶中的馏分.
为什么要分两个容器来接馏分呢?
加入的量是20ml 母液和70ml硫酸,怎么会有150-200ml的馏分收集呢?
是否我哪里理解错了
原文由 christe 发表:
为什么要分两个容器来接馏分呢?
为什么要分开两次滴定呢?
公式中为什么要乘2, Va为什么又要乘5?谢谢