Please fill in the following blanks in the experimental operation: ① When heating the substance with alcohol lamp, use the flame of alcohol lamp &; (=NationalBureauofStandards) ...

(1)(4 points) ① External flame? 2 check the purity? ③ Put a little water? (4) keep level.

(2)(9 points) 1 b? ②Ⅰ、Ⅲ、Ⅴ? 3 tweezers limestone? Dilute hydrochloric acid? 4 oxygen?

2H manganese dioxide 2H

This topic mainly investigates the basic experimental operation. The preparation of gas is one of the important contents of junior high school chemistry experiment, which is both difficult and hot. It is the key to solve this kind of problem to understand the reaction principle, the selection basis of the device, the methods of gas inspection, filling and collection, and the experimental steps and matters needing attention.