Question

What are the 4 different types of chemical reactions? And how to remember them

Answer 1

Adding on to C5h11no2, examples of the 4 chemical reactions are..
Synthesis A+B= AB (the two elements combine)
Decomposition: AB= A+B (the two elements breakdown)
Single Replacement: AB+C=AC+B (An element is switched with another from the reactant to the product)
Double Replacement: AB+CD=AC+BD (Both elements are switched with another from the reactant to the product)

Answer 2

Synthesis, decomposition, single replacement and double replacement.