Hazardous reagents or hazardous chemicals, have burns, explosive, toxic, corrosive or radioactive and other dangerous properties.By friction, vibration, impact, catches fire, or under the influence of water be affected with damp be affected with damp, strong light irradiation, high temperature, contact with other substances, such as external factors, can cause strong combustion, explosion and poisoning, such as burns, deadly severe accident.In the purchase, storage and use of a variety of hazardous chemicals in the process, must strictly comply with the relevant provisions of the state and product manual provisions shall apply.There are several kinds of dangerous chemicals that may be used in middle school chemistry experiments. Features: volatile, easy to burn in case of fire; the mixture of steam and air reaches the explosion limit; in case of fire, spark, electric spark can occur violent explosion.
1. The flammable liquid
Feature: the volatile, encounter flame burn easily;Vapor and air mixture reaches the explosion limit range, open flame, spark, edm are violent explosion can occur.
Example: gasoline, benzene, toluene, ethanol, ethyl acetate, acetone, acetaldehyde and ethyl chloride, carbon disulfide, etc.
Custody and the matters needing attention when using: (e.g., tightly capped bottle stopper) to seal to prevent dumping and spillover, stored in a cool, ventilated special cabinet, to stay away from the fire (including spark generating artifacts) and antioxidant.
2. Flammable solid
Features: low ignition, easy to ignite, its vapor or dust mixed with the air up to a certain degree, can open fires or Mars, electric spark intense burning or explosion;Contact with oxidant easy burning or explosion.
Example: nitrocellulose, naphthalene, camphor, red phosphorus, sulfur, magnesium powder, zinc powder, aluminum powder, etc.The preservation and the matters needing attention when using: with oxidant separately stored in shady and cool place, away from the fire.
3.Spontaneous combustion product
Features: with air contact caused by slow oxidation easily spontaneous combustion.
Example: white phosphorus (white phosphorus is also a highly toxic product)
Custody, and the matters needing attention when using: in water in the bottle, white phosphorus completely submerged underwater, stoppered, save in the shade.Don't contact with the skin when using, to prevent its spontaneous combustion caused by temperature is difficult to heal burns.
4.Dangerous When Wet
Feature: the reaction with water, produce combustible gases and release a lot of heat.
Example: potassium, sodium, calcium carbide, calcium phosphate, magnesium silicide, sodium hydride, etc.
Custody and the matters needing attention when using: in strong airtight container and stored in a cool and dry place.A small amount of potassium, sodium, should be on hold the bottle of kerosene, the potassium, sodium, completely submerged in kerosene, urinating in store.
Feature: friction, vibration, impact, encounter fire, high temperature can cause the fierce explosion.
Example:three nitro toluene, nitroglycerine, nitrocellulose, picric acid, mercury fulminate etc..
Custody and the matters needing attention when using: bottled separately stored in a safe place.When used to avoid friction, vibration, impact, catches fire.In order to avoid dangerous explosion, the experiment of dosage should be as less as possible.
6, strong oxidizer
Features: with reducing agent contact explosion.
Example: sodium peroxide, barium peroxide, sulfate, nitrate, potassium permanganate, dichromate, chlorate, etc.
Custody and the matters needing attention when using:Separate from acids, combustibles, and reducing agents,Store in a cool, ventilated place