What term best describes the type of reaction that happens when a molecule or compound reacts with another molecule or compound, producing two new molecules or compounds?

Answer: Double displacement reaction

Explanation: This could be the reaction of some soluble salts to give an insoluble salt plus soluble salt, for example

AgNO3 (aq) + Nacl (aq) →Agcl (s) + NaNO3 (aq)

Answer: Double replacement reaction

Explanation: Double replacement reaction also known as metathesis can be defined as a type of chemical reaction between two substances in which two parts of each substances are exchanged resulting in two new products (compounds or molecules). The cations and anions switch between two reactants to form new products.

A-B + C-D → A-D + C-B