Classify the following chemical reactions as exothermic or endothermic.

Question

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

Answer 1

Let's classify each of the chemical reactions based on the energy changes involved:

1. Fireworks explode. The Fireworks are the system.

   • Classification: Exothermic
   • Explanation: The explosion of fireworks releases energy in the form of heat and light to the surroundings.

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

   • Classification: Exothermic
   • Explanation: The increase in temperature indicates that heat is being released into the surroundings as a result of the chemical reaction in the hot pack.

3. The chemicals in a cold pack are mixed together and the temperature decreases. The cold pack is the system.

   • Classification: Endothermic
   • Explanation: The decrease in temperature indicates that heat is being absorbed from the surroundings, which is characteristic of an endothermic reaction.

4. A plant absorbs sun rays for photosynthesis. The plant is the system.

   • Classification: Endothermic
   • Explanation: Photosynthesis involves the absorption of sunlight (energy) to convert carbon dioxide and water into glucose and oxygen, making it an endothermic process.

In summary:

• Fireworks explosion: Exothermic
• Hot pack reaction: Exothermic
• Cold pack reaction: Endothermic
• Photosynthesis: Endothermic