Classify the following chemical reactions as exothermic or endothermic.(4 points)

Question

Exothermic Endothermic
Fireworks explode. The fireworks are the system.

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.

The chemicals in a hot pack are mixed together and the temperature increases. The hot pack is the system.

Answer 1

Here’s the classification of the chemical reactions:

Exothermic:

1. Fireworks explode. The fireworks are the system.
2. The chemicals in a hot pack are mixed together and the temperature increases. The hot pack is the system.

Endothermic:

1. A plant absorbs sun rays for photosynthesis. The plant is the system.
2. The chemicals in a cold pack are mixed together and the temperature decreases. The cold pack is the system.

In summary:

• Exothermic: Fireworks, hot pack
• Endothermic: Photosynthesis, cold pack