Homogeneous can be defined as “all of the same state” or “all of the similar kind”. Homogeneous in chemistry is referred to as mixtures of same kind that are uniform in composition, substances having the same character throughout the mixture forming a definite composition.
Mixture is made up of two or more different substances that are mixed together but do not combine chemically.
In a Homogeneous Mixture you will find, the different combinations of substances when mixed together form a consistent mixture throughout. Such kind of mixture where the appearance is similar, close-knit and uniform at the molecular level and the mixture appears to be physically same even when you let it settle for a long time is called a homogeneous mixture.
Particle size plays an important role in distinguishing homogeneous and heterogeneous mixtures.
Milk is an example of homogeneous mixture containing water, proteins, sugars and fats. What makes milk homogeneous is its uniformity, as the dissolved particles in milk are not visible to your eyes and won’t be visible even if you let it settle for a long time. But when you mix raisins and milk, it becomes a heterogeneous mixture, as your eyes can easily make out raisins in the milk. The mixture no more appears similar, uniform or homogeneous.
The most common examples of homogeneous mixture are air and water, both are an essential part of our daily lives.
A mixture is considered to be an important part of chemistry. Most of the things around us are in the form of a mixture. It is made up of two or more substances. Although the mixture has more than two substances, there is no chemical reaction between them, they are just a combination. A mixture can be further classified into two types, homogeneous and heterogeneous. As their name suggests ‘homo’ means similar and ‘hetero’ means different.
In layman’s terms, a mixture is made by combining two or more substances. In chemistry, a mixture is divided into two broad categories, homogeneous mixtures and heterogeneous mixtures. For now we shall restrict ourselves to homogeneous mixture and its examples.
What is Homogeneous Mixture?
Homogeneous Mixture: A homogeneous mixture is made up of two or more different substances which are in the same phase and in definite proportion, but do not undergo any chemical reaction. These substances are spread uniformly and look similar in appearance and composition throughout the mixture. If we divide the homogeneous mixture into equal halves, its components will have same amount in both the halves. The substance in the homogeneous mixture are in the same state, hence they are not visible with the naked eye. But the molecules of the substance can be differentiated under the microscope. For example: salt in water, blood plasma.
Heterogeneous mixture: Unlike homogeneous mixtures, a heterogeneous mixture is made up of two or more substances which can be in any phase – solid, liquid or gas. The substance can be in any proportion, but they do not undergo any chemical reaction. For example: Sand in water, oil in water.
• The substance forming homogeneous mixture is always in the same phase.
• They maintain uniform composition throughout the mixture.
• The particles of the mixture can be seen clearly by a microscope.
• Each constituent can be separated by chromatography, heat, filtration, centrifugation and evaporation.
• The properties of homogeneous mixtures are same as their constituent particles.
I guess, the concept of homogeneous mixture is now clear to you. The examples illustrated below will further help you to clearly understand homogeneous mixtures. Once you know the examples, you can experiment them at home.
Examples of Homogeneous Mixtures:
1. Water is the most common example. Water is made up of two basic constituent, hydrogen and oxygen that are in constant proportion with each other. The molecular formula of water is (H2O) and thus, it’s a homogeneous mixture. Water is also inert and the constituents do not react chemically with each other.
2. Salt or sugar solution comes under homogeneous mixture. You can make the solution by stirring two tablespoons of sugar or salt in a glass of water. Keep stirring until the particles completely dissolve. The solution will be transparent and homogeneous, and you won’t be able to distinguish the constituents.
3. Metal alloys are perfect examples of man made homogeneous mixtures. For example, bronze is an alloy of tin and copper. The elements are in constant ratio and thus a homogeneous mixture of alloy is formed. Similarly, steel is also an example of the homogeneous mixture formed by combining carbon and iron.
4. Air is a natural homogeneous mixture. The gases that formed air remain in constant proportion that makes the resultant mixture homogeneous. Gases that are dissolved in air are oxygen, carbon dioxide, nitrogen, sulfur, etc. They are in equal proportion and are in the same phases, owing to which air is a homogeneous mixture.
5. Naturally occurring mineral ore is also included under homogeneous mixture. Thus because, the various compounds forming an ore are in equal ratios. For example, ores of copper contain various forms of copper in the same proportion while iron ore contain different compounds of iron in the form of oxides, like magnetite, hematite, etc.
6. Your daily mouthwash is a homogeneous mixture example. The mouthwash liquid contains a percentage of alcohol along with a variety of different chemicals that make your breath fresh.
7. The commonly used laundry detergent for washing clothes is a mixture of various chemicals that form a soapy solution to keep your clothes clean.
8. A good branded perfume that you use on your clothes to keep you smelling good is again a mixture of various chemicals.
9. The Gunpowder also known as black powder is actually a mixture of sulfur, charcoal, and potassium nitrate.
10. The Cake batter from which your mom makes you a delicious cake is also a perfect example of man made homogeneous mixture.
11. A colloid or gelatin is a special type of mixture which contains intermediate sized particles between a solution and a suspension, common examples are Jello and Yogurt.
12. Other examples of homogeneous solutions are brewed coffee or tea, wine, gasoline, concrete, soapy water, wall paint, dilute hydrochloric acid, pure alcohol, honey and a glass of orange juice without pulp. All these are examples of pure solutions and the constituents cannot be distinguished from one another. The properties of the mixture are same as that of the constituents and thus, they form a good example of homogeneous solution.
The examples stated above are easy to understand, you can experiment them at home to prepare such solutions. Try to relate with the properties of homogeneous mixtures and then observe the individual particles under a microscope. Understanding mixtures is an important part of chemistry and you can definitely give a try.
A homogeneous mixture possesses some properties which are usually the combined properties of its constituents. Following are some of them.
• The substances in homogeneous mixtures are always in one phase.
• They are uniform in composition throughout the mixture.
• They cannot be seen with the naked eye but can be differentiated under the microscope.
• They can be separated by physical and chemical methods like crystallization, evaporation, distillation, chromatography, etc.
• The substance does not undergo any chemical reactions.
• They possess the properties of all its constituents.
As we discuss the examples of homogeneous mixtures, I want you to try them out to get a clearer idea of the whole concept. To bring more clarity on the subject I will explain you two very common examples of natural homogeneous mixtures and three examples of man-made homogeneous mixtures, you can observe and experiment with the latter ones and prepare your own list of man-made homogeneous mixtures on a worksheet for your science project.
Two Examples of Natural Homogeneous Mixtures:
1. Water can be considered as one of the most common examples of homogeneous mixture. Its molecular formula is (H2O). This means that water has two basic constituents hydrogen and oxygen. Apart from this it has many mineral ions and other dissolved gases like the sulfur, nitrogen etc.
2. Mineral ore is another natural example of homogeneous mixture. As Iron ore contains many other forms of oxides that include magnetite, goethite, limonite, hematite or siderite.
Three Examples of Man-Made Homogeneous Mixtures:
1. Sugar or salt solution is very common example of homogeneous mixtures. Take one glass of water and mix two tablespoons sugar or salt. Now stir till they are mixed. The solution will be clear and you will not be able to see particle. Now you can separate the sugar or salt easily from the water by the process of evaporation.
2. Metal alloy is also a good example of homogeneous mixture. These alloys are made to enhance the efficiency of the metal. Example: Steel is an alloy of iron and carbon and bronze is an alloy of copper and tin.
3. In your kitchen, the bottle of vinegar your mom uses for cooking and cleaning is a man made homogeneous mixture.
Now that you know what a homogeneous mixture is, apart from these examples mentioned above, there are many more examples of homogeneous mixtures like vinegar, air, gunpowder, brine solution, etc. So, just look around you and try to find out which all substances can be included in the list of homogeneous mixtures.
Don’t Forget: A homogeneous mixture is either made up of two or more similar or different particles in the same proportion. The mixtures are in the same proportion and are uniform throughout. Two different homogeneous mixture composed of same substances largely varies from each other, but they can be made homogeneous by implication of a constant factor. A solution is also considered to be a homogeneous mixture because the ratios of solute and solvent particles remain uniform throughout.
Types of Homogeneous Mixtures with Examples:
Solid Homogeneous Mixture – Alloys like Brass, Amalgam, Phosphor bronze, Pewter
Liquid Homogeneous Mixture – Alcohol in water, Vinegar, Gasoline
Gaseous Homogeneous Mixure – Air, Fog, Smog, Smoke
Here’s a video for you to better understand about mixtures: