There are many cool experiments that can help students see how energy changes during chemical reactions. Let’s look at some fun ways to explore exothermic and endothermic reactions.

Exothermic Reactions

1. Burning Fuels

• What You Need: A small piece of fuel (like a candle or some alcohol), matches or a lighter, and a calorimeter.
• What to Do: Light the fuel in a calorimeter filled with water. Watch the water temperature change.
• What You’ll See: When the fuel burns, it produces heat. This makes the water temperature rise. For example, burning 1 gram of octane gives off about 47 kJ of energy!

2. Dissolving Calcium Chloride

• What You Need: Calcium chloride, water, and a thermometer.
• What to Do: Put some solid calcium chloride into a cup of water and stir it.
• What You’ll See: The mixture will get warm, showing that heat is released when calcium chloride dissolves. The energy change for this process is around -82.8 kJ per mole.

Endothermic Reactions

1. Dissolving Ammonium Nitrate

• What You Need: Ammonium nitrate, water, and a thermometer.
• What to Do: Mix ammonium nitrate into a beaker of water and stir well.
• What You’ll See: The temperature of the water goes down, meaning it absorbs heat. The energy change for this reaction is about +26.4 kJ per mole.

2. Simulating Photosynthesis

• What You Need: Plant leaves (like the water plant Elodea), a light source, and water.
• What to Do: Put the plant in water and shine a light on it.
• What You’ll See: This doesn’t change the temperature much, but photosynthesis needs sunlight to turn carbon dioxide and water into sugar and oxygen. So, it absorbs energy from its surroundings.

Comparing What You See

• Temperature Change: In exothermic reactions, the temperature goes up. But in endothermic reactions, it goes down.
• Visual Signs: Exothermic reactions often feel hot and can create light, like when fuels burn. Endothermic reactions may feel cool or need heat from outside sources.

Conclusion

Doing hands-on experiments helps us understand exothermic and endothermic reactions better. These activities show clear changes in energy, making chemistry concepts easier to grasp and fun to learn!