As Roles denote relationships between things ActRelationships connect Acts, and fundamental ActRelationship types are component, specialization, and instantiation, but also cause (end effect), reason (motivation), and many more. Acts can be thought of in different stages of realization; on the one side being an event that is just happening, and on the other extreme is an Act considered only as a potential action. And between these extremes exist Acts that are intended, desired, requested, promised, and planned, or taken as a conditional. This dimension is known in human languages as "mood" of verbs. By representing the mood as a dimension, the HL7 RIM becomes extremely expressive as an information and knowledge representation schema without becoming more complex, because there are still just these 5 basic classes with a small set of generally useful attributes. This model has already been applied to the domain of chemical substances, and in this work, it is extended to Reactions. According to ISO IDMP substances may be specified in two opposite ways. The preferred way to specify a substance is by giving its chemical structure; however, for many medicinal substances, the exact structure may not be fully known or rather, there is no single chemical structure defining the substance, but it is a complex mixture of myriads of different molecules (structurally diverse). As an example, take "orange juice" or "coffee". These substances can only be defined by telling essentially how they are made from their source materials, while source materials are usually a product of some process, the ultimate source materials are biologic organisms, e.g., the orange plant, the coffee plant. The organism here may be defined by its genome or more generally by a literature reference to the authority who described it. An orange fruit or a coffee bean is a part of the organism, but it is not as simply a part as a wheel is part of a car. The fruit is harvested at the right time when it is ripe, separated from the plant and then processed by pealing, squeezing, winnowing, and roasting, etc. This understanding of structurally diverse substances as the product of a derivation process, has prepared the entire RIM based SPL substance model to represent any processes involving substances, which then includes chemical reactions.