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给试管里的固体加热

> 规范的操作是实验成功的前提，下列实验操作正确的是（　　） A．用电子天平称量氯化钠，应先调零，然后垫称量纸称取氯化钠 B．蒸发操作时，蒸发皿必须放在石棉网上，用酒精灯外焰加热 C．用排空气法收集气体时，导气管不需要插入接近集气瓶底 D．给试管内的固体药品加热时，试管口应略向下倾斜

问题：

发布时间：2024-09-10

规范的操作是实验成功的前提，下列实验操作正确的是（　　）

A．用电子天平称量氯化钠，应先调零，然后垫称量纸称取氯化钠

B．蒸发操作时，蒸发皿必须放在石棉网上，用酒精灯外焰加热

C．用排空气法收集气体时，导气管不需要插入接近集气瓶底

D．给试管内的固体药品加热时，试管口应略向下倾斜

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