题型:问答题 如下图所示装置,观察到“铁树”上浸有无色酚酞试液的棉团由白色变为红色。该实验中没有涉及的有关氨的性质是[ ]A.氨分子是不断运动的B.氨分子有一定质量C.浓氨水具有挥发性D.氨气易溶于水,氨气的水溶液显碱性 查看答案
题型:问答题 All electrical appliances aboard a vessel should be grounded to().A.prevent them from falling when the vessel rollsB.protect personnel from electrical shockC.increase their operating efficiencyD.prevent unauthorized personnel from operating them 查看答案