天气预报 > 其他 > 为什么实验中要进行减压过滤
为什么实验中要进行减压过滤
更新时间: 2020-07-03 00:00:00  

有些物质要在一定的大气压下进行实验,所以实验中要进行减压过滤 。减压过滤可加速过滤,并使沉淀抽吸得较干燥,但不宜过滤胶状沉淀和颗粒太小的沉淀,因为胶状沉淀易穿透滤纸,沉淀颗粒太小易在滤纸上形成一层密实的沉淀,溶液不易透过。循环水真空泵使吸滤瓶内减压,由于瓶内与布氏漏斗液面上形成压力差,因而加快了过滤速率,布氏漏斗上有许多小孔,滤纸应剪成比漏斗的内径略小,但又能把瓷孔全部盖没的大小。用少量水润湿滤纸,开泵,减压使滤纸与漏斗贴紧,然后开始过滤。当停止吸滤时,需先拔掉连接吸滤瓶和泵的橡皮管,再关泵,以防反

关键词: 为什么 实验 进行 减压 过滤

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