Three Balanced equations for Ammonium salt+Alkali=Salt+water+carbon dioxide

Compare and contrast physical changes with chemical changes.

Astudent reacts 13 moles of iron with 21 moles of oxygen according to the following equation:

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.