Three-state changes, shape changes, size changes, etc.

Common judgment methods

Such as: color, state, smell, hardness, etc.

Such as: combustion-supporting properties, flammability, oxidizing properties, etc.

Physical changes: color, state, volume....

Chemical changes: consumption of reactants and production of products

Narrow-mouth bottle: contains liquid medicines, which is conducive to pouring medicines and is not easy to spill.

Wide-mouth bottle: holds solid medicines, making it easy to put in and take out the solids

Gas collecting bottle: conveniently cover it with a frosted glass piece and seal it tightly to prevent air leakage

Such as brown thin/wide-mouth bottles: store substances that are easily decomposed by light

When the dosage of drugs is small, it can be used as a reaction vessel

It can be heated and ignited inside (the test tube must be preheated to prevent explosion)

When heating, a layer of asbestos mesh or clay mesh must be placed underneath.

Commonly used in gas production experiments (convenient to seal with a plug)

When heating, a layer of asbestos mesh or clay mesh must be placed underneath.

The bottle body has no edges and corners, and is evenly heated to enhance heat for a long time.

When heating, a layer of asbestos mesh or clay mesh must be placed underneath.

1. Pick out the jar with tweezers 2. Place the test tube horizontally and slowly lower it to the bottom (blocky)

1. Use a medicine spoon or paper trough 2. Slowly feed it to the bottom of the test tube (powder)

1. More liquid can be poured 2. Tilt the test tube and turn the stopper upside down 3. The label faces the palm of your hand

1. Use a dropper for less liquid 2. The sharp beak cannot enter the test tube.

Accurate weighing depends on the measuring cylinder, and the reading is usually concave to the liquid level.