This laboratory session is centered on exploring the impact of temperature on carbonated water, specifically examining how temperature variations influence the solubility of carbon dioxide (CO2) in water.
Utilizing three separate test tubes filled with sparkling water, each is placed in a distinct temperature setting: one in cold water with ice cubes, another in hot water, and the third at room temperature. The test tubes are allowed to acclimate to their respective temperatures before observations are made.
Educational Goals
- Observation of Temperature Effects on Carbonated Water: Participants will observe and note the differences in CO2 release and the appearance of sparkling water at various temperatures, aiming to compare the effects directly.
- Understanding Gas Solubility in Liquids: The experiment is designed to illustrate how temperature affects the solubility of gases in liquids, with a focus on how temperature variations alter water’s capacity to dissolve CO2.
- Application of Thermodynamics and Chemical Kinetics: This laboratory provides a practical context for applying concepts from thermodynamics and chemical kinetics, enhancing participants’ understanding of these fundamental principles.
Through this laboratory experience, participants will gain insights into the pronounced effects of temperature on the physical and chemical properties of liquids, particularly the dissolution phenomenon of gases in liquids.
Additionally, the experiment emphasizes the importance of conducting controlled experiments by carefully manipulating variables such as temperature, thereby strengthening experimental methodology skills. Furthermore, meticulous observation and thorough documentation of results are highlighted as crucial steps for drawing meaningful conclusions in chemistry. This session not only fosters a deeper understanding of the interplay between temperature and gas solubility but also enhances participants’ competencies in experimental design and analysis, underscoring the significance of precise scientific inquiry.
Protocol
1. Locate the three test tubes of carbonated water (with carbon dioxide (CO2)).
2. Fill one beaker with ice and cold water and the other beaker with hot water.
3. Using tongs and a universal stand, place the first test tube in a beaker containing cold water and ice cubes.
4. Using tongs and a universal stand, place the second test tube in a beaker containing hot water.
5. Leave the third test tube on the countertop at room temperature.
6. Wait 30 seconds for the test tubes to become sufficiently cold or hot before continuing.
7. Open the test tube left at room temperature and note your observations.
8. Open the test tube in the hot water and note your observations.
9. Open the test tube in the ice water and note your observations.
Anticipated Outcomes
Initially, the partial pressure of CO2 above the liquid in the test tubes is 150 kPa. An increase in temperature will decrease the solubility of CO2 in water. As there will be less CO2 dissolved in a warm liquid, there will be reduced effervescence in the warm container and increased effervescence in the cold container, compared to the container at room temperature.
The solubility of gases in liquids generally decreases with an increase in temperature. This behavior is opposite to that observed for most solids dissolved in liquids. When the temperature rises, the molecules of the solvent (the liquid) and the solute (the gas) gain more kinetic energy. This translates into faster and more vigorous movements of the liquid’s molecules, making it more difficult to keep the gas molecules in solution. The interactions between the gas and liquid molecules become less effective as the gas molecules are more easily ‘ejected’ from the liquid. This relationship is particularly important in natural and industrial processes. For example, in lakes and oceans, the water’s capacity to retain dissolved oxygen decreases as the temperature rises, which can have consequences for aquatic life. Similarly, in industrial systems where gases are dissolved in liquids, temperature management is crucial to maintaining the desired gas concentrations.
Summary of Assignment by Grade Range
Grades 3-5 (Ages 8-10)
- Focus: Basic introduction to gas solubility and temperature effects.
- Activities: Observing CO2 release from sparkling water at different temperatures, simple discussions on how temperature affects gas solubility, basic safety instructions.
Grades 6-8 (Ages 11-13)
- Focus: Intermediate understanding of gas solubility in liquids and temperature effects.
- Activities: Preparing test tubes with sparkling water at different temperatures, observing and recording CO2 release, understanding how temperature affects gas solubility, following detailed safety protocols.
Grades 9-12 (Ages 14-18)
- Focus: Advanced understanding of gas solubility, thermodynamics, and chemical kinetics.
- Activities: Setting up experiments with sparkling water at various temperatures, accurately measuring and recording observations of CO2 release, analyzing the relationship between temperature and gas solubility, detailed recording and interpretation of results, adhering to advanced safety protocols, reinforcing concepts of thermodynamics and chemical kinetics.
Laboratory essentials
Instruments
Beakers (100ml & 1000ml)
Electronic Scale
Test Tubes.
Products
Carbonated water (CO2)