Exothermic & Endothermic Reactions
Investigate energy transfer by measuring temperature changes during simulated exothermic and endothermic processes.
Start the exothermic reaction and observe the temperature increase.
🔥 Exothermic vs ❄️ Endothermic
Energy is transferred from the reacting system to the surroundings. In a simple calorimetry-style observation, the surroundings may become warmer.
Energy is transferred from the surroundings into the system. The measured surroundings may therefore become cooler.
🎯 Aim
To distinguish exothermic and endothermic processes by observing temperature changes and the direction of energy transfer.
🧰 Virtual Apparatus
Virtual reaction vessel, thermometer, timer, temperature graph, reaction controls and observation table.
ΔT = Tfinal − Tinitial
📘 Energy Transfer
The system is the chemical process being studied. Everything outside the system is considered the surroundings.
Endothermic: energy flows from surroundings → system.
📊 Simplified Energy Profile
🎯 Prediction Challenge
A reaction mixture starts at 25°C and rises to 36°C. Which description best matches the observed temperature change?
📋 Observation Table
| Trial | Process | Example | Initial Temp. | Final Temp. | ΔT | Energy Direction | Classification |
|---|---|---|---|---|---|---|---|
| No observations recorded. | |||||||
📝 Procedure
- Select Exothermic or Endothermic.
- Select one of the available educational example models.
- Select an initial temperature.
- Record the initial temperature.
- Press Start Reaction.
- Observe the thermometer and reaction vessel.
- Watch the direction of the energy arrows.
- Observe the temperature-versus-time graph.
- Calculate ΔT = Tfinal − Tinitial.
- Classify the process and record the observation.
🔥 Exothermic Example
Acid-base neutralisation is commonly exothermic. Energy released by the reacting system can warm the surrounding solution.
❄️ Endothermic Example
Some dissolution processes are endothermic. Energy is absorbed from the surroundings, which can cause the measured solution temperature to decrease.
🎓 Quick Viva
1. What is an exothermic process?
It is a process in which energy is transferred from the system to the surroundings.
2. What is an endothermic process?
It is a process in which energy is transferred from the surroundings into the system.
3. What happens to the surroundings in an exothermic reaction?
The surroundings receive energy and may become warmer.
4. What happens during an endothermic process?
The system absorbs energy from the surroundings.
5. How is temperature change calculated?
ΔT = final temperature − initial temperature.
6. What does a positive ΔT indicate in this simple experiment?
It indicates that the measured surroundings became warmer.
7. What does a negative ΔT indicate?
It indicates that the measured surroundings became cooler.
8. What is activation energy?
It is the energy barrier associated with initiating a reaction pathway.
9. Is combustion generally exothermic?
Yes. Combustion processes generally transfer energy to the surroundings.
10. Can an exothermic reaction require energy to start?
Yes. An exothermic reaction can still require activation energy before the reaction proceeds.
⚠️ Safety
This is a virtual experiment. Real chemical reactions may involve corrosive substances, hot solutions, flames, gases or other hazards. Laboratory experiments should be performed with appropriate equipment, protective measures and qualified supervision.
✅ Result
The virtual experiment demonstrates that an exothermic process transfers energy to the surroundings, while an endothermic process absorbs energy from the surroundings. Measuring temperature change provides useful evidence for identifying the direction of energy transfer in a controlled experiment.