Contextualization

Chemistry is the science that studies the composition and properties of matter and the changes it can undergo. At the core of chemistry are chemical reactions, which occur when two or more substances interact to form new substances. This project will focus on a fundamental aspect of chemistry: the different types of chemical reactions.

There are many types of chemical reactions, each with its own characteristics and rules. Some examples include synthesis, decomposition, replacement, and displacement reactions. Scientists classify chemical reactions into different types to facilitate their study and understanding. Just as we categorize animals and plants into different species and genera to study them better, we also categorize chemical reactions to better understand how they work.

Furthermore, understanding the theory behind chemical reactions is not only important for chemistry but also has many practical applications. Chemical reactions are the basis for many industrial processes, such as the production of medications, petroleum refining, and the manufacturing of plastics and other materials. Additionally, chemical reactions play an important role in many aspects of our daily lives, from cooking and cleaning to breathing and metabolizing food.

Learning about chemical reactions can not only help to better understand the world around you but also can open many doors to interesting and rewarding careers in fields such as chemistry, medicine, engineering, and more.

For this project, you can base yourselves on the following resources:

1. The video from the channel Ciência Todo Dia, "What happens when you throw sodium in water?", provides clear explanations and demonstrations of chemical reactions.

2. The book "Química: a ciência central", by Theodore L. Brown, is an excellent reference for basic concepts in chemistry.

3. The website "Tabela Periódica" offers a wide range of information about elements and their chemical reactions.

Remember: the best way to learn is through practice. So, let's get started!

Practical Activity: "Chemical Reactions in Practice"

Project Objective

This project aims to allow students to experiment and observe different types of chemical reactions in a practical and safe manner. Through these activities, students will be able to better understand key concepts about types of chemical reactions, the reactants and products formed, as well as develop technical and socio-emotional skills.

Detailed Project Description

Groups of 3 to 5 students will perform different types of chemical reactions and create a detailed report for each. Each group will perform three different types of reactions: synthesis, decomposition, and replacement. During the reactions, students should carefully observe what happens, document their observations, and then analyze the results.

Required Materials

• Safety goggles
• Laboratory gloves
• Lab coat
• Baking soda (NaHCO₃)
• Vinegar
• Glass balloon (Erlenmeyer flask)
• 2 burnt incandescent light bulbs
• Hammer
• Matches
• Filtered water
• Table salt (NaCl)
• Precision scale
• Stopwatch

Detailed Step-by-Step for Activity Execution

1. Synthesis Reaction: The synthesis reaction occurs when two or more substances combine to form a new substance. In this case, students will combine baking soda and vinegar to produce acetic acid, water, and carbon dioxide.

   1. Wear safety goggles, gloves, and lab coat.
   2. Place 15 grams of baking soda in a glass balloon.
   3. Add 100 ml of vinegar to the balloon and quickly close it.
   4. Observe the reaction and record everything that happens.

2. Decomposition Reaction: The decomposition reaction occurs when a single substance breaks down into two or more substances. In this case, students will decompose the tungsten filament (W) from a burnt incandescent light bulb.

   1. Wear safety goggles, gloves, and lab coat.
   2. Carefully break the incandescent light bulb with a hammer.
   3. Remove the tungsten filament.
   4. Light the filament with a match and observe the reaction.
   5. Record your observations.

3. Replacement Reaction: The replacement reaction occurs when a chemical element replaces another element in a compound. In this case, students will replace the sodium (Na) in table salt with the hydrogen (H) from water.

   1. Wear safety goggles, gloves, and lab coat.
   2. Weigh 5 grams of table salt and add it to 100 ml of filtered water.
   3. Stir until the salt dissolves and record your observations.

After performing the reactions, the groups should write a report, following the guidelines below:

1. Introduction: Describe the relevance of studying chemical reactions, contextualize the topic, and explain the project's objective.

2. Development: Explain the theory behind the three types of chemical reactions performed. Describe each activity in detail, including the materials used, the procedures performed, and the results obtained. Discuss the results, indicating the reactants, the products formed, and the type of reaction (synthesis, decomposition, or replacement).

3. Conclusion: Conclude the work by summarizing its main points and explaining what was learned from the project.

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

Each student is expected to dedicate 2 to 4 hours to the project execution, and the total time for report submission should be one week.