<u>Answer:</u>
1. Chemical reaction | Endothermic
2. Physical change | Exothermic
3. Chemical reaction | Endothermic
<u>Explanation:</u>
• Chemical reaction or Physical change?
A chemical reaction occurs when one or more substances converted into one or more different substances; they are usually irreversible.
A physical change occurs when the state of matter, or any other physical property, of a substance changes; they are usually reversible.
• Endothermic or Exothermic?
An endothermic reaction or change is one in which the system takes in thermal energy.
An exothermic change is where thermal energy is given out by the system.
