To reduce carbon dioxide emissions for chemical processes, one should make them as reversible as possible. Patel et al. [Ind. Eng. Chem. Res. 2005, 44, 3529-3537] showed that, in some cases, one can analyze processes in terms of their work and heat requirements. In particular, for processes, there exists a temperature that is called "the Carnot temperature", at which one can satisfy the work requirement for the process, using the heat that must be added or removed. The analogy of a heat engine and Carnot temperature is applied to chemical processes, particularly on reactive processes, using a graphical approach. This approach looks at chemical processes holistically, where only the inlet and outlet streams are considered. The process is represented in a Delta H-Delta G space. Chemical processes are classified in different thermodynamics regions as defined in the Delta H-Delta G space, and their feasibility in terms of heat and work requirement is discussed. This approach allows one to determine whether heat at an appropriate temperature is sufficient to meet the work requirement of a chemical process, or if other means should be considered. The approach is used to investigate and discuss the possibility of combining reactive chemical processes classified in different thermodynamic regions in the Delta H-Delta G space, with the purpose of making infeasible processes possible, or to minimize, or even eliminate, the work requirement of the combined process.