Differences Between Homogeneous and Heterogeneous Mixtures
Mixtures are a physical combination of two or more substances or elements. These substances that are combined together have no chemical interactions with each other and hence retain their inherent chemical properties. However, parameters like the melting point or boiling point are affected by the formation of a mixture.
Characteristics of a Mixture
- As none of the components of a mixture are chemically interacting with each other, separating components from a mixture is easy.
- The chemical properties of components are not altered in a mixture.
- A mixture can be formed by combining substances in any state of matter. Example: A combination of salt in water is a mixture; similarly, the soil is a mixture of particulate rocks.
- In a mixture, the components need not be present in definite concentrations.
- The formation of a mixture is not associated with any change in energy or enthalpy, unlike the formation of a new compound. Example: Formation of salt involves energy, as a bond is formed between the element sodium and chlorine. However, while preparing a salt solution, no energy is involved, as salt is evenly distributed in the water, and no chemical interaction occurs between salt and water.
Based on the states of matter of individual components (dispersion phase and dispersion medium) of a mixture. The mixtures can be:
- Solid in Solid
- Solid in Liquid
- Solid in Gas
- Liquid in Liquid
- Liquid in Gas
- Liquid in Solid
- Gas in Gas: Air
- Gas in Liquid
- Gas in Solid
Types of Mixtures:
There are two broad classifications of a mixture:
1. Homogeneous Mixture:
- Homo: the meaning of the term is ‘same or uniform’.
- A homogeneous mixture is a type of mixture in which the components are uniformly distributed.
- None of the components involved in the homogeneous mixture can be detected or observed separately.
- The homogeneous mixture is always confused with a substance, but the main difference is proportion. They both might appear to be the same, but in reality, substances are made of definite compositions. In contrast, homogeneous mixtures have no fixed composition and contain indefinite amounts of any component.
- A solution is a great example of a homogeneous mixture. When a solute completely dissolves in a solvent, the mixture formed is a solution. Here the solute is the dispersed phase, and the solvent is the dispersion media. Example of solution: salt+ water
- Another example of a homogeneous mixture is an alloy. An alloy is composed of different metals, all retaining their individual chemical properties. Example: Brass (an alloy of copper and zinc)
2. Heterogeneous Mixture
- Hetero: This term stands for different.
- A packet of gems is a classic example of a heterogeneous mixture. So, based on what is observed when we open a packet of gems, a heterogeneous mixture can be defined as a mixture with no uniformity.
- Individual components of a heterogeneous mixture can be discreetly observed.
- As the components are visible, it is easier to separate the individual components of a heterogeneous mixture than the homogeneous mixture.
- Colloids and suspensions are examples of heterogeneous mixtures.
- A colloid is an intermediate between a solution and a suspension. Here, the particle size of the solute ranges from 0.1 micrometers to 1 nanometer. The size of the particle is small enough to go undetected by the naked eyes but can be clearly observed under a microscope. Example: Milk. The solution of milk appears to be homogeneous but, in reality, is heterogeneous.
- Suspension: In a suspension, the size of the solute particle ranges from 1nm to 1000nm and can be clearly detected by naked eyes. Example: Sand in water.
- Soil is another example of a heterogeneous mixture, as it is composed of rock particles, clay, sand and more.
In order to summarize the two types of mixtures: homogeneous and heterogeneous, let us understand their differences.
|1. As homogeneous mixtures have a uniform composition, they are monophasic
|Owing to the non-uniformity of a heterogeneous mixture, they tend to be multiphasic (biphasic or triphasic)
|2. The components of a mixture are not visible by the naked eye
|The components of a heterogeneous mixture are visible even to the naked eye. Exception: Colloids
|3. Difficult to separate individual components by physical methods.
|As individual components can be observed, the components of a heterogeneous mixture can be easily separated by physical methods.
|4. Example: Salt in water
|Example: Sand in water