Contextualization

Chemistry is the science that studies matter, its properties, how and why substances combine or separate to form others, and how substances interact with energy. In this discipline, a key concept is that of the number of moles. Understanding this concept is essential for solving a wide variety of chemical problems and is also the basis for understanding many other concepts in chemistry.

What is a mole?

A mole is a basic unit of the International System of Units (SI) for the quantity of matter. In chemistry, we use the number of moles to convert between the mass of a material and the number of particles that material contains, whether atoms, ions, or molecules.

Avogadro's number (6.022 x 10^23) is the quantity of particles in a mole. This number is based on the number of atoms in 12 grams of carbon-12, and is used to convert between the atomic mass of an element (in atomic mass units) and its molar mass (in grams per mole).

Why is it important?

Understanding the concept of moles is essential for understanding and calculating chemical reactions. Being able to convert between the mass of a material and the number of particles it contains allows us to predict and control the proportions of reactants and products in a chemical reaction. This plays a crucial role in a wide variety of fields, from the industrial production of chemicals to laboratory research.

A very practical example of using the concept of moles is in cooking. When preparing a recipe, such as bread, it is necessary to balance the quantity of each ingredient correctly so that the chemical reaction occurs correctly and the bread rises. Failure in this balance can result in an inadequate final product.

For more information on the concept of moles, we recommend the following reliable resources:

• Khan Academy. (n.d.). "What is a mole?". Khan Academy
• YouTube. (2014). Introduction to Moles | The Chemistry Journey | The Fuse School. YouTube

Practical Activity

Activity Title: Moles and Cookies

Project Objective:

Students will understand the practical application of the concept of moles through the preparation of a cookie recipe and, using the concepts of moles, will calculate the amount of molecules present in the recipe.

Detailed Project Description:

To carry out the project, each group of 3 to 5 students must follow the following steps:

1. Research a simple cookie recipe that contains at least the following ingredients: flour, sugar, butter, chocolate, and eggs.
2. Calculate the amount of moles of each ingredient based on the recipe found. Remember that 1 mole of a substance is equal to its molar mass (in grams).
3. Execute the recipe.
4. Calculate the amount of molecules of each ingredient present in the cookies using Avogadro's number.
5. Prepare a detailed report of all the steps taken, from the choice of the recipe, through the calculations performed, to the conclusion and analysis of the results obtained.

Required Materials:

• Internet access for recipe research
• Ingredients for the chosen recipe
• Kitchen scale for mass measurements
• Kitchen utensils for cookie preparation
• Calculator
• Paper and pencil for calculations and notes

Detailed Step-by-Step:

1. Research a simple cookie recipe on the internet. Write down the ingredients and their quantities in grams.
2. Calculate the amount of moles of each ingredient. Use the formula: n = m/M, where n is the amount of moles, m is the mass (in grams), and M is the molar mass of the ingredient (in g/mol).
3. Make the cookies following the chosen recipe.
4. Now, calculate the amount of molecules of each ingredient you used. Use Avogadro's number (6.022 x 10^23 molecules/mol) to convert moles to molecules.
5. Finally, compare the amounts of moles and molecules of each ingredient. Write your reflections and conclusions.

Project Deliverables:

Groups must submit a detailed report of the project, following the format below:

Introduction: Provide context for the project, explaining the importance and practical application of the concept of moles. Identify the chosen recipe and explain the reason for it.

Development: Describe in detail the activity carried out, from the choice of the recipe to its execution. Include the calculations made to determine the amount of moles and molecules of the ingredients. Present and discuss the results obtained.

Conclusion: Summarize the main points of the project and explain what was learned from this activity.

Bibliography: Cite all sources of information used in the project.

This report must be submitted one week after the start of the project. Evaluation will take into account both the accuracy of the calculations and the understanding of the theoretical fundamentals involved and the practical application of these concepts.

Remember, the goal is to learn and have fun exploring the chemistry present in our daily lives! Good luck!