Question

What are the types of chemical changes?And what are they?

Answer 1

There are five types of chemical reactions:

1. Combination/Synthesis Reactions: two or more substances combine to form a new compound (A+X->AX). Includes, but is not limited to, the reactions of elements with Oxygen and Sulfur; the reactions of metals with Halogens; and Synthesis reactions with Oxides.
2. Decomposition Reactions: a single compund undergoes a reaction that produces two or more singular substances (AX->A+X).
3. DisplacementReactions: when a substance in a compund is replaced by a substance outside of the compound (A+BX->B+AX). Possible replacements include: metals by another metal; Hydrogen in water by metal; Hydrogen in an acid by a metal; and Halogens by more active Halogens.
4. Double Displacement Reactions: when ions of two compounds exchange places in aqueous solutions to form two new compunds (AX+BY->AY+BX). One of the compounds formed is usually a precipitate, an insoluble gas that bubbles out of the solution, or a molecular compound (usually water).