Which of the following statements holds true for a chemical change?

a. in a chemical change, no new substance is formed
b. in a chemical change, a substance changes its phase
c. in a chemical change, the molecular structure of a substance changes
d. in a chemical change, one substance dissolves into another

Aglow stick contains a glass vial with chemicals. when the glow stick is bent, the vial breaks and the chemicals react to produce a glow. a science student observes that a glow stick kept in the freezer glows for a longer duration than a glow stick kept at room temperature. what conclusion can be drawn based on the observation? be sure to note the outcome and test variables in the conclusion.