1. Experimental steps: dissolution, filtration and evaporation.

Second, the role of glass rod:

(1) Stir during dissolution to accelerate dissolution.

(2) Drainage during filtration.

(3) When evaporating, stir and heat evenly.

Third, filter attention points: one post, two low, three rely on.

Precautions for evaporation: stir with a glass rod and evaporate the filtrate with waste heat.

Put a small amount of raw salt into a beaker, add a proper amount of water and stir with a glass rod. After the original salt is completely dissolved, pour the turbid brine into the installed filter along the glass rod, and then heat the filtrate in an evaporating dish until a large number of solids appear in the filtrate, and stop heating.