Introduction

Our world is packed full of mixtures: air, blood, orange juice, steel, the Earth's crust, and countless others. In chemistry, a mixture is a material that contains two or more substances which are not chemically combined. These substances retain their own chemical properties, and these substances may be of any phase: solid, liquid or gas.

We have Homogeneous mixtures, also known as solutions, which have the same proportions of the components throughout any given sample. For example, in air, the proportions of nitrogen, oxygen, and other components is the same throughout all samples. Conversely, Heterogeneous mixtures have varying proportions of their components throughout any sample. Examples are granite and a bowl of fruit salad.

The ability to separate mixtures into their individual components is an essential skill in chemistry. Many natural substances exist as mixtures and we often need to isolate particular components from a mixture for further use. The separation techniques we use are based on the type of mixture and difference in the chemical properties of the constituents of a mixture.

Contextualization

Separating mixtures is not only important in a laboratory setting but also has practical implications in daily life. For instance, the water we drink or the air we breathe are not as pure as they seem, they are mixtures of several things. We purify our drinking water to remove unwanted salts and contaminants. The atmospheric air is a mixture of several gases like oxygen, nitrogen, carbon dioxide, and others. To obtain these gases in their pure forms used for industrial purposes, we need to separate them from air.

In industry, mixtures are often separated to yield either a useful product or a component that can be reused. For example, crude oil is a mixture of many different hydrocarbons which are separated in refineries to produce gasoline, jet fuel, diesel fuel, heating oil, and many other products.

Below are some resources to deepen your understanding of the project theme:

1. Mixtures and Solutions (CK-12)
2. Separating Mixtures (BBC Bitesize)
3. Methods for Separating Mixtures (Chemistry LibreTexts)
4. Separation of Mixtures (Khan Academy)

Practical Activity

Activity Title: "Extracting Salt from Rock Salt: A Study in Mixture Separation”

Objective of the Activity

To understand and apply the process of dissolving, filtration, and evaporation as a method for separating a mixture into its individual elements.

Detailed Description of the Project

In this activity, the students will be working with rock salt, a common example of a mixture. Rock salt consists of salt (sodium chloride) and various impurities such as sand and other salts. The goal of the project is to separate the salt from the rest of the mixture, using a series of separation techniques.

Necessary Materials

• Rock salt
• Water
• A beaker
• A Bunsen burner
• Heat resistant gloves
• A filter paper
• A funnel
• Safety goggles

Note: Safety is key to this activity. Always remember to wear your goggles and gloves while handling the Bunsen burner.

Detailed Steps

1. Dissolving: Each group of students should place about 50 grams of the rock salt mixture into the beaker, then add 200 mL of water. Stir the mixture until as much salt as possible has dissolved. We are using the fact that salt is soluble in water, while the other impurities are not.

2. Filtration: Next, set up a filtration system using the funnel and filter paper. Pour your mixture through the filter. The sand and other insoluble substances will remain in the filter, while the salty water (filtrate) will pass through into another beaker.

3. Evaporation: Finally, heat the filtrate gently using the Bunsen burner until the water has evaporated, leaving only salt. Remember to handle the hot beaker with heat-resistant gloves!

Your end goal is to separate as much salt as you can from the rock salt mixture, leaving behind the other impurities. This process mimics real-world scenarios such as water purification and crude oil refinement.

Written Document

After the completion of the practical part of the project, each group must collaborate to write a document in the format of a report containing:

• Introduction: Here, contextualize the theme of mixtures and their separation, its relevance and real-world application. Explicitly state the objective of the project.
• Development: Detail the theory behind the separation of mixtures, and the use of dissolving, filtration, and evaporation in this process. Explain the activity your group performed in detail, including the methods used and the results you achieved.
• Conclusion: Reflect on your findings and what you have learned about the process of separating mixtures. Mention the skills you developed during this project, such as teamwork, time management, problem-solving, and proactivity.
• Bibliography: Indicate the sources you relied on for your research and understanding of the subject. These may include books, web pages, videos, etc. Remember to use proper citation format!

Duration of Project

The practical activity should take about two hours to complete, while the writing part of the project will vary depending on the group's work dynamic. The entire project should be completed within one week.

Group Size

This activity should be carried out in teams of 3-5 students in order to promote collaboration. Each team member should contribute to both the practical and written parts of the project.

This hands-on experience, paired with an emphasis on teamwork and report writing, aims to provide a comprehensive understanding of the topic at hand. It will delve into the practical aspect of the separation of mixtures, while also fostering vital socio-emotional skills. Good luck, and have fun!