Here are the classifications for the chemical reactions you provided:
Exothermic:
- Fireworks explode. The fireworks are the system.
- The chemicals in a hot pack are mixed together and the temperature increases. The hot pack is the system.
Endothermic:
- A plant absorbs sun rays for photosynthesis. The plant is the system.
- The chemicals in a cold pack are mixed together and the temperature decreases. The cold pack is the system.
Summary:
- Exothermic: Fireworks, hot pack
- Endothermic: Photosynthesis, cold pack