Basic reaction types of junior middle school chemistry

There are four basic reaction types in junior middle school chemistry: combination reaction, decomposition reaction, displacement reaction and double decomposition reaction.

1. Combination reaction: A reaction in which two or more substances form another substance, which is called a combination reaction. The common chemical reactions in junior high schools mainly include: nonmetallic simple substances and oxygen generate nonmetallic oxides; Metal reacts with oxygen to generate metal oxide; The metal oxide reacts with water to generate corresponding alkali; Non-metallic oxides react with water to produce corresponding acids.

2. Decomposition reaction: A chemical reaction that produces two or more other substances from one substance is called decomposition reaction. The common decomposition reactions in junior high school are: decomposing insoluble carbonate at high temperature; Heating to decompose insoluble alkali; Acid salt is decomposed by heating; Alkaline salts decompose when heated.

3. Displacement reaction: The reaction between a simple substance and a compound to form another simple substance and another compound is called displacement reaction. The common substitution reactions in junior high school are: the reaction of active metal (before hydrogen in metal active sequence) with acid; Active metal is added to the salt, and water-soluble salt is added to the metal with lower activity; Reducing metal oxides with hydrogen; Carbon reduces metal oxides.

4. Double decomposition reaction: The reaction in which two compounds exchange components to form two other compounds is called double decomposition reaction. The common double decomposition reactions in junior high school are: acid plus basic oxide, salt plus water; Acid and alkali, salt and water (neutralization reaction); Acid with salt, new acid with new salt; Alkali with salt, new alkali with new salt; Salt A is added with salt B, and new salt C is added with new salt.