To dream of a chemical represents a forced or guaranteed reaction. Feeling that if you do something or saying something to someone that a certain outcome is absolutely insured to occur. Perfect manipulation of a person or situation.
Negatively, a chemical in a dream may be a sign that you are risking going overboard or hurting yourself to make something happen.
To dream of mixing or combining chemicals represents a collaboration of ideas to insure a desired reaction from a person or situation. Creativity or intelligent manipulation. Negatively, mixing chemicals may reflect risky manipulation with things you are not experienced or prepared enough for. Being completely unprepared for the type of reactions you may get from people you are toying with.
Example: A woman dreamed of putting a chemical into a fire extinguisher to put out a fire and then realized afterwards that some people use this chemical to commit suicide. In waking life the woman had a fight with her boyfriend and wanted to fix it. She mentioned marriage to him to show how serious she was about fixing their relationship. She later realized that mentioning her wish to marry him was a bit dangerous because some people mention marriage to partners when they want the other person to feel uncomfortable with their neediness and break up with them.