Contextualization

Osmotic pressure is an intriguing and widely applied phenomenon that occurs in nature and in our daily lives. It is an important concept in chemistry and biology and plays a fundamental role in many natural and industrial processes. Osmosis is the process by which solvent molecules tend to pass through a semipermeable membrane from an area of lower solute concentration to an area of higher concentration, generating a pressure known as osmotic pressure.

For example, water can be purified through the process of reverse osmosis, where a pressure higher than the osmotic pressure is applied to force water through a membrane, cleaning it from impurities and solutes. In biology, osmotic pressure is essential for the proper functioning of cells, as it controls the passage of water and solutes through the cell membrane.

Learning about osmotic pressure and how it applies to the world around us is an integral part of studying chemistry. In this project, we will explore the concept of osmotic pressure through laboratory activities, group discussions, and individual research.

Osmotic pressure is a term you may not hear every day, but it has great relevance and application in the real world. It is the pressure needed to prevent the diffusion of water through a permeable membrane. This is vital for our bodies, as our cells need to maintain a proper water balance to function correctly. Additionally, osmotic pressure is also used in many industrial processes, such as desalinating seawater to make it potable.

To delve deeper into osmotic pressure and its applications, you can consult the following reliable resources:

1. Khan Academy - Osmosis and Osmotic Pressure
2. Brasil Escola - Osmosis
3. InfoEscola - Osmotic Pressure
4. Física e Química - Osmosis and Osmotic Pressure

Practical Activity

Activity Title: The Pressure of Salt - Exploring Osmotic Pressure in Practice

Project Objectives

1. Understand osmotic pressure and its relationship with solute concentration and temperature.
2. Apply the concepts learned to calculate osmotic pressure.
3. Develop teamwork, time management, and theoretical-practical application skills.

Detailed Project Description

In this project, each group of 3 to 5 students will conduct an experiment to measure the osmotic pressure of a salt solution at different concentrations and temperatures. The experiment involves creating a simplified osmotic cell and measuring changes in water level due to osmotic pressure. This activity requires about 15 hours to complete, spread over two weeks.

Required Materials

1. U-tube
2. Precision balance
3. Solvent (water)
4. Solutes (salt and sugar)
5. Semipermeable membrane (plastic films)
6. Rubber bands
7. Thermometer
8. U-tube holders
9. Magnetic stirrer
10. Stopwatch

Detailed Step-by-Step

1. Weigh different masses of salt and sugar using the precision balance and record the values.
2. Dissolve the solute samples in water in different containers to obtain solutions of different concentrations. Note the water temperature.
3. Attach the semipermeable membrane to one end of the U-tube using rubber bands. Ensure it is well sealed.
4. Fill the sealed side of the tube with one of the prepared solutions and the other side with pure water to the same level.
5. Place the tube on a stand so that both sides are at the same height.
6. Observe and record the change in water level on the solution side and the pure water side every 10 minutes for an hour.
7. Repeat the experiment for all prepared solutions, observing and noting the temperatures and water level changes.
8. From the data obtained, calculate the osmotic pressure, considering the difference in water height as a reference.
9. Compare the results obtained for the different solutions and temperatures.

Project Deliverables and Connections to Activities

At the end of the practical activity, students should present a comprehensive report, including the following topics:

1. Introduction: Provide context for osmotic pressure, its importance and real-world application, and the purpose of the experiment conducted.

2. Development: Describe the theory of osmotic pressure and the relationship between pressure, solute concentration, and temperature. Explain in detail the experiment conducted, the methodology used, the calculations performed, and discuss the results obtained in relation to the theory studied.

3. Conclusions: Summarize what was learned from the project, the observations made, the difficulties encountered, and the proposed solutions. How do the results obtained relate to the theory of osmotic pressure? What were the impacts of variations in solute concentration and temperature on osmotic pressure?

4. Bibliography: List all sources consulted for the project, including books, videos, websites, etc.

This multidisciplinary project involves concepts from chemistry, physics, and biology, providing students with a learning experience that integrates different areas of knowledge.

Remember: the quality of the report and the clear presentation of results are as important as the correct execution of the experiment. Aim for a well-structured, clear, and objective report that illustrates the group's learning throughout the project.