Lesson Plan | Active Learning | Colligative Properties: Colligative Properties Problems

Assumptions: This Active Lesson Plan assumes: a 100-minute class, prior student study with both the Book and the start of Project development, and that only one activity (among the three suggested) will be chosen to be conducted during the class, as each activity is designed to take up a significant portion of the available time.

Objectives

Duration: (5 - 10 minutes)

This stage of the lesson plan is crucial for laying the foundations upon which students will build their practical knowledge. By clearly defining the objectives, students will have an accurate understanding of what is expected of them and what they need to achieve by the end of the lesson. This also helps to guide activities in the classroom, ensuring that time is efficiently used for application and practice of the concepts of colligative properties.

Main Objectives:

1. Empower students to solve problems involving colligative properties, especially those related to freezing point depression, boiling point elevation, and vapor pressure.

2. Develop the ability to apply previously studied theoretical concepts in practical and calculation situations, thereby reinforcing the understanding of the impact of colligative properties on the behavior of solutions.

Side Objectives:

1. Encourage collaboration among students in problem-solving, promoting group learning and the exchange of ideas.

Introduction

Duration: (15 - 20 minutes)

The introduction aims to engage students and contextualize the importance of colligative properties in everyday situations and practical applications. By presenting problem situations they may encounter in daily life or future careers, the lesson becomes more relevant and motivating. Furthermore, by briefly discussing the history and impact of colligative properties in real situations, students can see the applicability and curiosity of the topic, thus increasing interest and attention for subsequent activities.

Problem-Based Situations

1. Imagine a chef preparing a dish that requires the use of brine to season the meat. He needs to know how salt affects the freezing point of water since the brine must remain liquid for the meat to absorb the flavors. How could the chef calculate the final freezing point of the brine?

2. Consider a laboratory needing to purify a water sample. They decide to use distillation to remove impurities, but they know that pure water boils at 100°C. How can knowledge of colligative properties help determine the boiling point of water with impurities?

Contextualization

Colligative properties are fundamental in many practical contexts, from food preservation to drug production. For example, by understanding how salt can reduce the freezing point of water, we can better comprehend the process of salting and preserving perishable foods. Additionally, studying these properties can reveal curiosities, such as why roads are often salted in winter to melt ice, or how marine animals survive in very salty waters.

Development

Duration: (70 - 80 minutes)

This stage of the lesson plan is designed to allow students to practically and interactively apply the concepts of colligative properties they have previously studied. Through playful and contextualized activities, students can explore the real and theoretical applications of these concepts, developing calculation, experimentation, and critical thinking skills. The proposed activities aim to consolidate theoretical knowledge in problematic and practical situations, promoting significant and lasting learning.

Activity Suggestions

It is recommended to carry out only one of the suggested activities

Activity 1 - Freezing Party: The Chef's Challenge

> Duration: (60 - 70 minutes)

- Objective: Apply the concept of freezing point depression in a practical and creative situation, developing calculation and experimentation skills.

- Description: Students will be divided into groups of up to 5 people and take on the role of chefs in a cooking competition. Each group will receive a list of ingredients and the task of creating a dessert that involves the use of colligative properties, such as freezing point depression. They will need to calculate the amount of a solute (e.g., salt) necessary for the mixture to remain in a liquid state at a specific temperature, considering the influence of salt on the freezing point of water.

- Instructions:

• Divide the class into groups of up to 5 students.

• Give each group a list of ingredients and their respective typical freezing temperatures.

• Ask each group to create a dessert that utilizes colligative properties, such as freezing point depression.

• Guide students to calculate the exact amount of a solute necessary to achieve the desired temperature of the mixture.

• Each group should prepare the dessert and present the calculation process and the final execution to the class.

Activity 2 - The Scientists' Secret Laboratory

> Duration: (60 - 70 minutes)

- Objective: Understand and apply the concept of boiling point elevation in a water purification context, fostering creativity and problem-solving ability.

- Description: In this playful activity, students, divided into groups, will play the role of scientists in a secret laboratory trying to develop a new method for purifying water. They will use knowledge of colligative properties to determine the boiling temperature needed for purification, considering the boiling point elevation with the addition of a solute.

- Instructions:

• Divide students into groups of up to 5.

• Present the problem situation: they need to purify a water sample but cannot use conventional methods.

• Provide each group with information about the water sample and the available solute.

• Guide students to calculate the amount of solute necessary to raise the boiling point of the water to a temperature that ensures purification.

• Each group should set up a small experiment (simulated) to demonstrate the effectiveness of their method.

Activity 3 - Road Challenge: Engineering Solutions

> Duration: (60 - 70 minutes)

- Objective: Develop a practical and sustainable solution to a real problem using knowledge about colligative properties, promoting critical thinking and collaboration.

- Description: Students, in groups, will assume the role of engineers tasked with creating an effective and sustainable solution for ice control on roads during the winter. They will need to use knowledge about colligative properties to design a mixture that helps melt ice, considering environmental and safety factors.

- Instructions:

• Divide the class into groups of up to 5 participants.

• Explain the situation of an ice-covered road and the need for a solution that minimizes environmental damage.

• Provide information about different solutes that can be used and their colligative properties.

• Guide students to calculate the best combination of solutes for the desired effect.

• Each group should present their solution, justifying it based on the principles of colligative properties.

Feedback

Duration: (15 - 20 minutes)

The purpose of this stage of the lesson plan is to allow students to reflect on the practical and theoretical learning obtained during the activities. The group discussion helps to consolidate knowledge, allowing students to articulate what they learned and hear different perspectives and solutions. Additionally, the key questions proposed aim to assess students' understanding of the topic and their ability to apply the concepts in varied contexts, promoting a deeper and more critical understanding of colligative properties.

Group Discussion

At the end of the activities, gather all the students for a group discussion. Start with a brief introduction, explaining that the goal is to share discoveries and challenges faced during the activities. Then, ask each group to present a summary of what was done and discussed, emphasizing the solutions found and the difficulties overcome. Encourage students to relate practices with the theoretical concepts of colligative properties.

Key Questions

1. What were the main challenges in applying the concepts of colligative properties in the practical activities?

2. How did the solutions proposed by different groups vary and why?

3. How can the knowledge acquired about colligative properties be applied in real situations outside the classroom?

Conclusion

Duration: (5 - 10 minutes)

This final stage of the lesson plan serves to consolidate learning, ensuring that students have a clear and integrated understanding of the concepts of colligative properties. Furthermore, by linking theory to practice and everyday life, the conclusion helps students see the importance and applicability of the acquired knowledge, motivating them to continue exploring and learning more about Chemistry.

Summary

In the conclusion, the teacher should summarize and recapitulate the main concepts addressed regarding colligative properties, such as freezing point depression, boiling point elevation, and vapor pressure. The formulas and calculations performed by students during the activities should be highlighted, reinforcing the practical application of these concepts.

Theory Connection

It is crucial to emphasize how the practical activities carried out in the classroom, such as the chef's challenge, the secret laboratory, and the road challenge, connect directly with the theory studied previously. Explain how the calculations and experiments conducted by students reflect directly the phenomena observed in colligative properties, strengthening understanding and the importance of studying these properties in daily life and applied science.

Closing

Finally, the teacher should discuss the relevance of colligative properties in daily life, from food preparation to industrial applications and environmental preservation. This moment is important for students to recognize the significance of what they have learned and how they can apply this knowledge in real situations, contributing to a greater appreciation of the study of Chemistry.