Final answer:
Elements of compounds exchange to form two different compounds in a double-replacement reaction, where parts of two ionic compounds are exchanged to create two new compounds.
Step-by-step explanation:
In a double-replacement reaction, elements of compounds exchange to form two different compounds. A double-replacement reaction is a chemical process where the positive and negative ions of two ionic compounds exchange places, resulting in the formation of two new compounds. The general form of a double-replacement reaction can be represented as AB + CD → AD + BC, where AB and CD are two compounds that react to form two new compounds, AD and BC.
Single-replacement reactions, conversely, involve the replacement of one element in a compound by another element, following the pattern A + BC → AC + B, where A replaces B in the compound. Synthesis reactions, on the other hand, involve the simple combination of two or more substances to form a single new substance, and decomposition reactions deal with the breakdown of a compound into two or more different substances.