Calorimetry and Cooling Curve Experiment Analysis

Abstract

Calorimetry is a crucial technique for measuring heat changes in chemical reactions, distinguishing between exothermic and endothermic processes. In this experiment, we calibrated thermometers and observed a cooling curve for paraffin wax. The digital thermometer proved more accurate than the liquid-filled thermometer for most measurements, but the liquid-filled thermometer excelled in determining the melting point.

Introduction

Calorimetry is the science of quantifying heat exchanged in chemical reactions, aiding in the classification of reactions as exothermic or endothermic. Proper calibration of equipment is essential to obtain accurate results.

In this experiment, we calibrated thermometers using freezing and boiling points of water. Additionally, we examined a cooling curve to understand state changes in paraffin wax.

Methods

Calibrating Thermometers

We calibrated thermometers by following these steps:

1. Fill a container with cold water.
2. Add ice cubes to the mixture and stir for approximately 3 minutes.
3. Place the thermometer inside the container, ensuring it does not touch the container's edges.
4. Record the temperature when it stabilizes at 0°C (32°F) to complete the calibration.
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To calibrate a thermometer for boiling water:

1. Place the thermometer in a container with freshly boiled water.
2. Ensure the thermometer displays the natural boiling point of water, which is approximately 100°C.

Cooling Curve

We created a cooling curve using paraffin wax, recording temperature changes at specific time intervals.

Results

Calibration Results

Discussion

In our experiment, the digital thermometer displayed higher accuracy for most measurements due to its ability to record temperatures to one decimal place.

The liquid-filled thermometer, on the other hand, provided whole number readings. However, the liquid-filled thermometer outperformed the digital thermometer in determining the melting point, recording it accurately at 0°C.

Cooling Curve Analysis

A cooling curve represents state changes in materials with temperature as the dependent variable and time as the independent variable. Our cooling curve for paraffin wax showed a gradual decrease in temperature as it transitioned from liquid to solid state.

Conclusion

In conclusion, our experiment demonstrated the importance of calibrating thermometers for accurate temperature measurements. The digital thermometer offered superior accuracy for most temperature readings, while the liquid-filled thermometer excelled in determining the melting point. The cooling curve for paraffin wax displayed the gradual transition from liquid to solid state, providing valuable insights into phase changes.

Calorimetry remains a fundamental technique in chemistry, enabling researchers to study heat changes in chemical reactions. Accurate calibration of equipment is essential to ensure reliable results, and understanding cooling curves can aid in predicting and analyzing phase transitions.