Background

The separation of mixtures is a fundamental technique in many areas of knowledge, from conducting scientific experiments to preparing food in our kitchens. In Chemistry, the study of the separation of mixtures is of utmost importance to understand how different substances interact with each other and how we can manipulate them to obtain specific results.

Mixtures can be homogeneous or heterogeneous and we can find them in various everyday situations. In the food we prepare, in the medicines we take, in the water we drink: all these are mixtures that go through some type of separation process to reach us. For example, the coffee we drink is made through an infusion, which is a way of separating mixtures.

Introduction

Throughout this chemistry project, you will be challenged to explore two processes for separating mixtures: decantation and distillation. Both are widely used in research laboratories and in industry, each being appropriate for a type of mixture.

Decantation is a separation process that is based on the difference in densities of the components of the mixture. It is widely used to separate immiscible liquids, such as oil and water, or an insoluble solid in liquid, such as sand and water.

Distillation is a process that is based on the difference in boiling points of the components of a mixture. Examples of the use of this method include the purification of water, the production of alcoholic beverages, and the distillation of petroleum in refineries.

To delve deeper into the subject, we suggest you consult the following resources:

• Book "General Chemistry" by John B. Russell: This book provides an introduction to the subject in a didactic and in-depth way.

• Khan Academy website: The Khan Academy has a section dedicated to Chemistry, where you can find videos and texts about the separation of mixtures.

• "Mundo Educação" website: This website has detailed explanations about the processes of decantation and distillation.

Practical Activity

Title of the activity: "Exploring Chemistry: Separation of Mixtures using Decantation and Distillation"

Objective of the project:

The objective of this project is to consolidate the students' knowledge of the concepts of distillation and decantation, in addition to developing teamwork skills, time management, and practical laboratory skills.

Detailed description of the project:

The project will be carried out in groups of 3 to 5 students and will consist of two main stages. In the first stage, the groups will have to prepare a mixture and carry out the decantation process. In the second stage, the groups will have to prepare a different mixture and carry out the distillation process.

The activity will be guided by a detailed experiment script that will guide the students in the preparation and separation of the mixtures. The estimated time for the execution of the project is 5 to 10 hours per student.

Necessary materials:

• Beaker (500 mL)
• Glass rod
• Funnel
• Filter paper
• Water
• Oil
• Sand
• Salt
• Scale
• Distillation kit
• Bunsen burner or heating plate
• Ethyl alcohol

Detailed step by step:

1. Form the groups and distribute the necessary material.

2. First stage: Decantation.

   • Mix water and oil in the beaker, stir the mixture with the glass rod.
   • Wait until the two phases separate.
   • With the aid of the funnel and filter paper, separate the phases and compare the result.
   • Repeat the procedure by mixing sand and water and compare the result.

3. Second stage: Distillation.

   • Dilute a known amount of salt in water (the density should be measured on a scale).
   • Perform the simple distillation procedure, collecting the distillate in a separate container.
   • Repeat the procedure using ethyl alcohol and water, this time performing a fractional distillation.

4. After carrying out the experiments, each group should prepare a detailed report. The report should be structured in sections: Introduction, Development, Conclusions, and Bibliography.

• In the introduction, students should contextualize the importance and application of the separation of mixtures in everyday life and the objective of the project.
• In the development section, students should explain the theory of decantation and distillation, explain in detail the performance of the experiments, the methodology used, and discuss the results obtained.
• In the conclusion, the students should reiterate the main points of the project, express the lessons learned and the conclusions found about the methods of separation of mixtures.
• In the bibliography, students should indicate the sources they used to base the project on.

Remember: the quality of the report is as important as the execution of the practical activity. Therefore, dedicate adequate time to its preparation!