Make Your Own Calorimeter
Measuring the energy in a reaction seems like an abstract concept- how can you measure something that isn't finite? How are you supposed to capture it? Luckily, calorimetry allows you to do so by utilizing water. You can measure the water's change in temperature to find how much heat came from the reaction because the heat released in reaction will equal the heat gained by the water.
List of Materials
- 1 styrofoam coffee cup
- 100 mL distilled water
- 1 thermometer
- 1 piece of cardboard slightly larger than the coffee cup
- 1 rubber band
- any amount of reactants you wish to test (in this case we'll use 5 grams of calcium chloride)
- Pour the 100 mL of distilled water into the coffee cup
- Cut a hole in the piece of cardboard large enough for the theremometer to fit through, and use the rubber band to keep the thermometer in place
- Place the lid on the cup and measure the temperature of the water
- Measure the temperature of the water alone
- Keeping the thermometer in the water, place the 5 grams of calcium chloride into the water.
- Gently begin swirling the cup, stopping every 20 seconds to record the change in temperature
- After 3 minutes, the change in temperature is the amount of heat the water has absorbed.
This heat the water has absorbed is called delta T, or . You can multiply this number by the mass of the water (easily found by placing it on a scale), and the heat capacity of the water, 4.184 joules per gram Celsius to find the amount of heat. The equation ends up looking like this- , with m being the mass of water and C being the heat capacity of the water. Finally, you can divide Q by m to determine the amount of heat per gram the reaction released.
1. Use the results from your experiment. How much heat per gram is released in this reaction?
2. How is this useful to scientists in the real world? How could it be useful to the average person?
3. How could you alter the experiment to be more efficient?