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5 Ways to Teach Mixtures: Homogeneous or heterogeneous

Nabiha Khalid
High School
Teaching with Labster

Introduction Mixtures: Homogeneous or heterogeneous

A mixture is a substance made of two or more additional chemical substances and compounds that do not chemically combine. The only way for two or more substances to maintain their individual identities when combined in the form of solutions, suspensions, or micelles is through physical mixing. Physical means can be used to separate them. Any type of chemical reaction does not create the different components of any mixture. As a result, each component's unique properties are unaltered. In another phrase, a mixture is something you get once you combine these two things, allowing you to separate them again without causing a chemical reaction. Every component in a mixture maintains its unique chemical identity. A mixture may possess unpredicted physical properties in contrast to both of its components, even though each component is unaltered. For instance, when alcohol and water are combined, the resultant substance has a different point of melting and boiling than either of the individual components.

Homogeneous mixtures are those with a constant composition throughout the substance. For instance, air, lemonade, carbonated beverage water, a mixture of water and salt, a mixture of water and sugar and so forth. The mixture of salt and water serves as a prime illustration here. This is due to the fact that salt and water cannot be separated at this point. The path of light is invisible when a ray of light strikes a solution of salt and water. On the other hand, heterogeneous mixtures are those that lack uniformity throughout. In the same vein, mixtures that do not have a uniform composition, such as soil and sand, sulfide and iron filings, oil and water, etc., are heterogeneous. This is due to the fact that it has a number of distinct phases in this situation.

Heterogeneous mixtures, on the other hand, are those that lack uniformity throughout. In the same vein, mixtures that don't have a uniform composition, such as soil and sand, sulfide and iron filings, oil and water, etc., are heterogeneous. This is due to the fact that it has a number of distinct phases in this situation.

A mixture's physical properties differ from its constituent parts' physical properties.

Students find Mixtures: Homogeneous or heterogeneous, a challenging subject. Why?

1. Confusion among mixture and solution

Materials with two or more chemical substances diffused throughout them are called mixtures (mixed together). Two materials combine to form a mixture if there is no chemical reaction. The components' chemical composition remains unchanged. Physical techniques can be used to separate mixtures. Solutions are homogeneous mixtures in which particles of two different substances—the solute and the solvent, such as salty water—are combined. Heterogeneous mixtures are large accumulations (clusters) of constituent substances, such as an oil-in-water emulsion.

2. Misconceptions among students

Most 'pure' substances we come into contact with in daily life are actually a combination of different chemicals. There is a lot of misunderstanding regarding the distinction between ordinary purity (such as "100% pure orange juice") and chemical purity (i.e., materials that only contain particles of one chemical substance). It is important to stress that learning science involves both learning a foreign skill and picking up concepts and skills. Despite their willingness to describe carbonated soda as tasting sweet, many students believe that the solute's mass is lost as it vanishes into the solution when solutions form. They might hardly ever realize that a mixture's properties depend on its precise composition. Finally, despite water being a very popular solvent, students hardly ever recognize it as particulate. Students' drawings of sugar diluting in water frequently feature sugar particles against a background of continuous water.

3. Blurred mental image

The number of new words to gain knowledge and the level of precision required for use can intimidate students who are studying how to use technological language correctly. The word "stuff" is a good place to start because, despite not being a recognized scientific term, it has a fixed meaning for most students and serves as a good linguistic stepping stone. Students comprehend that the world is composed of various materials, each of which has unique properties. It is our responsibility to guide them past their sensory-based understanding of the world and into the submicroscopic realm, where various chemical elements are arranged in various ways. Students can develop their understanding by using physical models as a hook. Show them a set of pots with identical plain beads, beads of the same size but different colors, and beads of the same color but different sizes, for instance. Given that the last two contain beads that are different in size or color, the students should recognize them as mixtures. Invite students to share their justifications with the class, then invite others to either agree or disagree and describe why. Encourage those making complex arguments to go further with their logic. For the third pot, for instance, "Is it sufficient to say that the beads differ as they have different sizes? Would you use the same justification for apples of various sizes? Students who are asked questions of this nature may be encouraged to think about an object or substance's qualities beyond its outward appearance.

5 ways to teach Mixtures: Homogeneous or heterogeneous.

1. Examples from daily life

Engage the students by giving them real-world examples of the subject, like the mixture of particles that make up smoke are suspended in the atmosphere. Tap water is a heterogeneous mixture containing water and other substances. Distilled water is a general term for pure water, also known as H2O. The air we breathe, which is made up of gases like oxygen and nitrogen, is one of the many mixtures we encounter daily. A device known as a centrifuge can separate blood into its two main components, serum, and red blood cells. Liquid, gaseous, and solid mixtures can all be homogeneous. Sulfur powder and iron filings are frequently used heterogeneous mixtures.

2. Properties of homogeneous and  heterogeneous  from routine

It's crucial to provide examples from daily life to help them understand homogeneous and heterogeneous mixtures. For instance, aside from solutions and alloys, the majority of mixtures have the characteristics of heterogeneous mixtures. Here, the presence of the constituent particles is not uniform. Effective distinctions can be made between the parts. In a heterogeneous mixture, at least two phases are typically available.

On the other hand, the characteristics of a homogenous mixture make all solutions instances of that type of mixture. The particles in this scenario are smaller than one nanometer in size. They fail to show Tyndall's influence. The limits of particles are not separable. Centrifugation or decantation cannot be used to separate the component particles in this situation.

3. Perform some fun activity

Activities are incredibly beneficial for removing misunderstandings and developing concepts. Ask students to complete easy tasks they can complete at home. Students should reflect on the following query: "What does pure mean?" As a prompt, show the students a picture of a "100% pure orange juice" bottle and an image of a piece of copper. Students should think about it on their own before having a pair discussion. Talk about the concept of purity in daily life. Students will hold a variety of opinions, ranging from pure, which is good, ideal, or perfect, to the scientific view that "contains only one chemical substance." Make a note of a few of these on the platform so that you can return to them later in the lesson.

4. Provide visual aids

Embrace the idea that something can combine with another without formulating a chemical bond. These biological ideas would be much easier for students to understand if they were depicted graphically. Thanks to technological advancements that educators can take advantage of, the use of 3D models or video representations of events like equitably distributed compounds could be made possible in the classroom. If students saw a visualization of the division of cells like the one given below, that is, an instance of such a representation, they would be intrigued and eager to learn more about it.

5. Use virtual lab simulations

For students, the mixture can be a broad and perplexing subject. By offering both homogeneous and heterogeneous mixture 3D simulations, Labster provides the solution to this problem. Labster's virtual laboratory simulations will simplify your lecture delivery and lab management sessions. You might be able to make more thought-provoking arguments because students are given access to visual alternatives. We provide assistance using gamification and interactive simulations. This interactive, immersive teaching approach is used by our virtual classroom /platform to reinforce fundamental ideas for aspiring scientists. To fill in the gaps in the accessible educational materials and address the lack of visually appealing video graphical possibilities in the educational space, you can use Labster's Mixtures: Homogeneous or heterogeneous? Virtual Lab in your upcoming class.

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References

https://chem.libretexts.org/Bookshelves/Introductory_Chemistry/Introductory_Chemistry_(CK-12)/02%3A_Matter_and_Change/2.09%3A_Heterogeneous_Mixtures 

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