1.几个“先后”1加热试管时,先均匀加热,后局部加热;2制取气体时,先检查装置气密性后装药品;3使用容量瓶、分液漏斗、滴定管前,先检查是否漏水后洗涤干净;4用排水法收集气体后,先移出导管后撤酒精灯;5用石蕊试纸、淀粉KI试纸检验气体性质时,要先用蒸馏水将试纸润湿,再靠近气体检验,而用pH试纸 1 several “successively” 1 heating test tube, the first uniform heating, after the local heating; 2 Preparation of gas, first check the device after the airtight drug; 3 use volumetric flask, separatory funnel, burette before, First check to see if there is leakage after washing; 4 after collecting the gas drainage method, first remove the catheter retraction alcohol lamp; 5 with litmus paper, starch KI test strip test gas properties, the first dip with distilled water to wet the test strip, Test, and use pH test paper