Contextualization

Theoretical Introduction

Solubility is a physical property of matter and refers to the ability of a solute to dissolve in a solvent. It is a fundamental concept to understand many natural phenomena and industrial processes, such as the manufacturing of medicines and foods, water purification, among numerous other examples.

The solubility of a substance can be affected by various factors, including temperature, pressure, and the nature of the substances involved. In the case of temperature, for example, its increase generally increases the solubility of solid substances in liquids, but decreases the solubility of gases.

Solubility is usually expressed in grams of solute per 100 grams of solvent, and at a given temperature. The mass of solute that dissolves in the solvent until saturation is reached is called the solubility coefficient.

Contextualization

Solubility is a concept very present in our daily lives, although we may not always realize it. Let's think, for example, when we prepare a cup of coffee. The amount of coffee we can dissolve in hot water is a practical example of solubility.

Furthermore, solubility plays a fundamental role in many industries, such as pharmaceutical and food industries. In the pharmaceutical industry, for example, the solubility of a medication directly affects its effectiveness, as if the medication does not dissolve properly, it will not be absorbed by the body.

Here are some reliable references to deepen the study on solubility:

1. Solubility Experiments - Brasil Escola
2. Solubility Theory - Chemistry - InfoEscola
3. Factors Affecting Solubility - Khan Academy (Video)

Practical Activity

Activity Title: Solubility in Action

Project Objective

This project aims to provide students with a practical and meaningful experience of how solubility works in daily life and how temperature affects the solubility of some substances.

Detailed Project Description

Students, in groups of 3 to 5, will carry out a simple solubility experiment. Throughout this experiment, students will vary the temperature of the solvent (water) to observe and measure how this affects the maximum amount of solutes (salt and sugar) that can be dissolved.

Required Materials

1. Salt (approximately 500g)
2. Sugar (approximately 500g)
3. Water
4. 3 Transparent containers (glass or transparent plastic cups)
5. Thermometer
6. Measuring spoons
7. 3 Portable burners or heating plates
8. Stopwatch

Detailed Step-by-Step

STEP 1: Students should measure and record the initial temperature of the water in each container.

STEP 2: Next, they should add a spoonful of salt to the water in one of the containers and a spoonful of sugar to the water in another container. The third container will be the control, where no substance will be added.

STEP 3: Students should record the time required to completely dissolve the solute in each container without heating. They should gently stir until they can no longer see any grains of salt or sugar.

STEP 4: Next, students should repeat the process for each substance, but this time heating the water. They should record the time required to dissolve the solute and the water temperature.

STEP 5: Finally, students should compare the results: the dissolution time and water temperature with and without heating.

Project Delivery

After completing the practical part, students should write a report containing the following elements:

Introduction: Students should explain solubility and its importance, in addition to giving a brief description of the experiment they conducted.

Development: In this section, students should detail the experiment, including the list of materials used, the procedure followed, and the data collected. They should also include a discussion of the results.

Conclusion: Students should summarize their findings and reflect on what they learned from the experiment. They should connect their results with what they learned about solubility and discuss any interesting observations or insights that arose during the experiment.

Bibliography: Finally, students should list all the references they used to carry out the project. For example, the websites where they read about solubility, the videos they watched to learn about the experiment, etc.

By following these steps, students will be learning about solubility in an interactive and practical way, as well as developing other important skills, such as interpreting results, teamwork, and technical writing.