Homogeneous vs Heterogeneous
Homogeneous and heterogeneous are two different words distinguished by the context in which they are used. Materials, mixtures, reactions, etc are classified as homogeneous or heterogeneous. But the difficulty of identifying the difference between these two mostly arises at the classification of mixtures.
Homogeneous means that something is uniform throughout the mixture or whatever the classification is based on. When homogeneous materials are considered, its composition and properties are the same throughout. Metals, alloys, ceramics and plastics fall into the category of homogeneous materials. In homogeneous mixtures, the mixed substances cannot be identified because, throughout the mixture, it is in one uniform phase and components cannot be seen individually. For instance, air, salt dissolved in water are taken as homogeneous mixtures. Homogeneous mixtures are called solutions. An alloy is a solid solution which can also be considered as a homogeneous solid mixture. Bronze, a solid solution of copper and tin, is an example for a homogeneous mixture. Components in a homogenous mixture cannot be separated by a mechanical method. In fact, the particle size of a mixture affects the nature of homogeneity. In a homogeneous mixture, the particle size is in the atomic level or the molecular level. When considering reactions, homogeneous reactions occur at the same phase.
The opposite term of homogeneous is heterogeneous. Non uniformity is the meaning of the word. For example, a composite fiberglass is a heterogeneous material. Unlike homogeneous materials, these materials have different structures and different compositions throughout. If we take a heterogeneous mixture, it is apparent that it contains more than one component in the mixture. But in some cases, components in heterogeneous mixtures can only be visible at the microscopic level. Normally, but not always, the components in heterogeneous mixtures can be separated using a mechanical method. A mixture of water and sand, suspension of sulfur in water, and granite are some of the examples for heterogeneous mixtures. In heterogeneous mixtures, the properties are not uniform throughout; thus, the components in a heterogeneous mixture can be separated based on the property variation. For example, a mixture of plastic and iron particles, which is a heterogeneous mixture, can be separated based on their density variation or different magnetic properties. Heterogeneous mixtures contain larger particles. Suspensions are heterogeneous mixtures. In the case of reactions, heterogeneous reactions occur at different phases.
Based on the uniformity or the non uniformity, homogeneous and heterogeneous can be differentiated. However, to classify under homogeneous and heterogeneous, the context should be given.
What is the difference between Homogeneous and Heterogeneous?
• Homogeneous materials and mixtures have the same uniform composition and properties throughout, while heterogeneous materials and mixtures do not have either uniform composition or uniform properties.
• Usually, but not always, heterogeneous mixtures can be separated using a mechanical method based on property variation of different constituents present in the mixture.
• In most cases, the components in heterogeneous mixtures can be identified visually. For some cases, it should be observed through a microscope. Components in homogeneous mixtures cannot be identified.
• In homogeneous mixtures, atomic or molecular level particles are present, but in heterogeneous mixtures particles are larger than the atomic or the molecular level.
• In the case of reactions, heterogeneous reactions occur at different phases, while homogeneous reactions occur at the same phase.