The term 'chemically change' refers to a process in which a substance undergoes a chemical reaction, resulting in a different substance. The two crossword solutions for this term are 'REACT' and 'INERT'. REACT is a verb that means to act or take action in response to something, while INERT is an adjective that describes a substance that does not REACT with other substances. Therefore, the two crossword solutions together suggest that a substance can be chemically changed by either reacting with another substance or remaining INERT.