Question

when you observe a chemical property, the substance... remains the same. glows. changes to a new substance. goes through a phase change.

Explanation:

Chemical properties are observed when a substance undergoes a chemical change, which results in the formation of a new substance. A phase - change is a physical change, and a substance doesn't necessarily glow when its chemical property is observed. Also, it doesn't remain the same during a chemical change.

Answer:

C. changes to a new substance