Context

This project focuses on studying the concepts of Dissociation and Ionization, two fundamental processes in Chemistry that play a crucial role in several areas, ranging from Medicine to Environmental Sciences. Dissociation is the separation of ions from ionic compounds in an aqueous solution, while Ionization refers to the removal or addition of electrons from an atom or molecule to form ions. These two processes are essential in understanding the formation of ionic substances and the chemical reactivity between different substances.

To put these concepts into a broader context, it is important to have a solid understanding of atomic structure, the difference between ions, molecules and compounds, as well as the role of water as a universal solvent. Chemical reactivity usually depends on the capacity of an atom or molecule to gain or lose electrons. Therefore, understanding Ionization is crucial to understanding chemical reactions. Similarly, Dissociation will help us understand how aqueous solutions of ionic substances work.

The processes of Dissociation and Ionization find extensive applications in many aspects of our daily life and the world around us. In Medicine, for example, Dissociation is essential for drugs to work. Many drugs are ionic compounds that need to dissociate into their constituent ions to exert their therapeutic effect. Similarly, in Environmental Chemistry, Ionization is fundamental to understanding how pollutant substances behave in the atmosphere.

The following resources can be useful to deepen your knowledge about Dissociation and Ionization:

• "Chemistry: The Central Science" book by Theodore L. Brown, H. Eugene LeMay Jr., Bruce E. Bursten, Catherine Murphy, Patrick Woodward and Matthew E. Stoltzfus (10th Edition or newer)
• YouTube channel "Química em Ação" videos, by professor Paulo Valim, that address several Chemistry topics in a clear and objective way.
• "Toda Matéria" website, Chemistry section, with several articles and detailed explanations about many Chemistry concepts, including Dissociation and Ionization: https://www.todamateria.com.br/dissociacao-ionica/ and https://www.todamateria.com.br/ionizacao/

Hands-on Activity: "Ion Hunter!"

Project Goal

The objective of this project is to allow students to apply the concepts of Dissociation and Ionization in a practical way. Students should perform experimental activities that demonstrate Dissociation and Ionization, and investigate how these processes occur.

Project description

Groups of students (3 to 5 students per group) will conduct an experimental activity about Dissociation and Ionization, performing a series of experiments that show these processes in action. Each group has to report the experiments, results and observations in the form of a lab journal.

Required Materials

• Safety gear (lab coats, goggles, gloves)
• Various ionic and covalent compounds (such as NaCl, MgSO4, sucrose, citric acid)
• Distilled water
• Beakers
• Spatulas
• pH test strips
• Heat source (Bunsen burner or hot plate)
• Thermometer

Step-by-Step

1. Preliminary Study: Review the provided learning material and any other sources to become familiar with the concepts of Dissociation and Ionization.

2. Preparing the Experiment: Using the distilled water, prepare solutions of the provided ionic and covalent compounds. Observe and write down which substances dissolved completely, which ones formed a suspension, and which ones did not dissolve at all.

3. Observing Dissociation and Ionization: Now, for each solution, test the pH using the pH test strips. Write down the observations. The solutions that present a pH change indicate the formation of ions by Dissociation or Ionization.

4. Temperature Analysis: Gently heat each solution and see if there is any change in the Dissociation or Ionization. Measure and write down the temperature of each solution before and after heating.

Project Deliverables

The groups of students will have to present a detailed project report, containing the following sections:

• Introduction: contextualize the theme, its relevance and applications in the real world, as well as the goal of the project.

• Development: here the student must describe the theory behind Dissociation and Ionization, explain the activity in detail including the methodology used, and finally present and discuss the results obtained. It will be important to detail all the steps of the experiment, the observations and the results, as well as their discussion in relation to the theoretical concepts.

• Conclusion: in this part, the student must revisit the main points of the work, highlight the lessons learned and the conclusions drawn from the project. They should reflect on how the experiment helped to understand the processes of Dissociation and Ionization.

• Bibliography: students should list all the sources they used to carry out the project, such as books, web pages, videos, etc.

The project should be delivered after four weeks. This is a project of medium difficulty and each student is expected to spend between five to ten hours in total to complete it.