Contextualization

The study of mixtures is a fundamental part of chemistry and permeates many aspects of our daily lives. From diluting a juice to preparing a medication, mixtures are present in virtually everything we consume and use.

Even more specifically, in this project, we will be focusing on mixtures where no chemical reaction occurs, meaning that the components are mixed but their individual properties are maintained, without the formation of new substances.

Introduction

In the universe of chemistry, mixtures in which no reaction occurs between the components are called homogeneous or heterogeneous mixtures. In homogeneous mixtures, also known as solutions, the different substances mix uniformly, without the separation between them being visible. In heterogeneous mixtures, it is possible to distinguish the different components with the naked eye or with the help of a microscope.

To understand the mixing processes, it is important to understand the concepts of solute, solvent, and solution. The solute is the component of the mixture that will be dissolved, the solvent is the substance that dissolves the solute, and the solution is the result of the mixture between solute and solvent. The concentration of the solution describes the amount of solute that has been dissolved in a certain amount of solvent and is usually measured in grams of solute per liter of solvent (g/L).

Furthermore, another important topic to be addressed is solubility, which is the ability of a solute to dissolve in a solvent.

Practical Activity

Activity Title: Exploring Mixtures without Reaction!

Project Objective

The objective of this project is to explore the physical nature of mixtures without reaction, deepen the knowledge about solutions, solubility, and the preparation of solutions with different solutes and solvents.

Detailed Project Description

The groups will be responsible for creating mixtures without reaction using different solutes and solvents, where they will observe and measure the characteristics of these mixtures.

Each group will:

1. Select three different substances to act as solutes (salt, sugar, baking soda, for example).

2. Select three different substances to act as solvents (water, alcohol, oil, for example).

3. Create all possible combinations of these substances, that is, 9 mixtures in total.

4. Measure and record the solubility of each solute in each solvent.

5. Prepare and analyze the physical properties of the homogeneous and heterogeneous mixtures obtained.

6. Write a detailed report of the experiment and the conclusions drawn.

Required Materials

Each group will need the following materials:

• Three different and labeled solutes: e.g. Salt, sugar, and baking soda.
• Three different and labeled solvents: e.g. Distilled water, alcohol, and oil.
• Nine transparent containers to mix the solutions.
• Funnel and filter paper (for separation of heterogeneous mixtures, if necessary).
• Scale to measure the quantities of solutes.
• Measuring spoons or pipettes to measure the solvents.
• Clock or timer to record the dissolution time.
• Camera or cell phone for documentation.

Detailed Project Steps

1. Form groups of 3 to 5 students. Each group should meet and decide on which solutes and solvents they will use.

2. Each group should weigh the same amount of each solute and record this quantity.

3. Each group should measure the same amount of each solvent and record this quantity.

4. Next, the students should mix each solute with each solvent, one at a time, recording their observations. The students should note the time it takes for the solute to dissolve in each solvent (or if it does not dissolve), color changes, sediment formation, among others.

5. In case of heterogeneous mixtures, use the funnel and filter paper to separate solute and solvent, if necessary.

6. After conducting the experiments, students should take photos of the mixtures obtained and attach them to the project report.

7. Finally, students should analyze the collected data, draw conclusions, and write the final project report.

Project Submission

The final project submission will be a detailed report of the entire process and final conclusions. This report should include:

• Introduction: In this section, students should contextualize the theme, explain its relevance and real-world application, as well as the objective of this project.

• Development: Here, students should detail the theory behind mixtures without reaction, explain the activity in detail, indicate the methodology used, and finally present and discuss the results obtained and the photos of the mixtures.

• Conclusion: Students should summarize their main points, explaining the learnings obtained and the conclusions drawn from the project.

• Bibliography: Students should indicate the sources they relied on to work on the project. This includes books, web pages, videos, etc.

The project duration should be one month, with an estimated total of five to ten hours of work per student.