Physical chemistry is a crucial aspect of relationships: it plays a major role in determining the level of attraction and compatibility between two individuals. It is often the starting point for any relationship, as it is the initial spark that can lead to deeper connections and bonds. It is important for individuals to be attracted to each other in order for the relationship to be successful. Physical chemistry in relationships is essential in the attraction and compatibility between two individuals that you primarily feel in your body. It is a combination of physical and emotional attraction.