We all know about elements. They are the basic materials or the main building blocks of everything on the earth. Some of the things of daily uses are just made up of a single element. Such things include copper pennies, iron nails, and neon lights. But most of the things we found around us are just not made up of one element; most of them are combinations of two or more elements. These combinations of the element(s) can be broadly classified into three categories. These categories are mixtures, solutions, and compounds. This chapter focuses mainly on the first two categories.
One very evident example of a mixture is soil. A shovelful of soil is composed of some topsoil, some clay, maybe a little sand, a few bugs, maybe some really tiny microorganisms, including a worm, or some rotting plant roots, and maybe some more organic and inorganic things. The soil is thus a mixture of multiple things. Yet we can say that each shovelful of soil is probably not the same as the next one. Maybe one has more percentage of sand, and the other has more clay. The components of soil can be classified into its different parts – the organic part and the inorganic part. The bugs, worms and plant parts form the organic part whereas the inorganic part is that of sand and clay. From this example, we can conclude that a mixture is not the same for all the samples, and a mixture can be segregated into its component parts.
On the other hand, salt water is an example of a solution. A glassful of salt water is made up of both salt and water in it. The salt remains dissolved evenly throughout the water, so in this case, a spoonful of the salt water would contain the same amounts of salt and water as another spoonful of the saltwater taken from the same glass. Salt water can also be separated into its component parts. If the water is allowed to evaporate, and we will have just have the salt left. Salt water is a solution and not a mixture because of its these two distinguishing characteristics: the concentration of each of its parts throughout the solution is same and uniform, and it can be separated into its components by some physical process.
Mixtures are broadly classified into two main groups: mechanical mixtures and solutions. Both are considered mixtures as both of them are composed of two or more different kinds of particles.
It is not always easy to identify whether a given matter is a mixture or not. We can confirm that soil is a mixture because the different parts are visible to us. If different kinds of matter in a mixture are visible, then it is known as a mechanical mixture. Mechanical mixtures are better known as heterogeneous mixtures. Often confusions arise between “Mixture” and “solution” and the concept is not clear.
The homogeneous mixtures containing one or more solutes in a solvent are termed as solutions. The solvent is the matter present in a maximum proportion in the solution, whereas a solute is a substance that remains dissolved inside the solvent. Some mixtures do not seem to be mechanical mixtures. They appear to be pure substances. Like the grape juice or clear shampoo that gives the impression as if composed of only one kind of matter. However, both grape juice and clear shampoo are solutions. Grape juice is composed of water particles, sugar particles, and flavor particles. Shampoo also has water particles, detergent particles, color particles, and scent particles. Mixtures that appear as if they are pure substances are called solutions. A solution like a mixture always have more than one kind of particle, but it appears as a pure substance. Solutions are often referred to as homogeneous mixtures. Both steel and seawater are solutions. The atmosphere surrounding the earth is a solution as well.
Any homogeneous mixture can exist in any of the three states: solid, liquid, or gas. However, in any one solution, only one state is visible. But this doesn’t happen in the case for heterogeneous mixtures. The heterogeneous mixture can have multiple states in one mixture.
Thus, in short, a mixture is a unification of substances where they are mixed up and yet their properties in physical terms would remain unchanged. An example of this can be of a fruit salad with condensed milk. If the fruit salad and condensed milk are mixed, both will end up yielding the same physical properties. Even after that, we can identify, which is the condensed milk and which are the different fruit components. However, in a solution, it is not the same. A solution involves dissolving of the substances into a new form of a solution, like in milk tea. To make a milk tea, once milk is dissolved in tea, we cannot separate the milk in the tea again.
DIFFERENCE EXPLAINED FURTHER
To put it in simple terms, we can say that a mixture is a substance composed of other substances mixed together but not joined together, while in a solution has a substance made of two or more substances are in unison. Moreover, a chemical reaction occurs in order to create a solution, but in a mixture, it is just physical mixing devoid of any chemical reactions.
• Points to recall: Mixtures are materials containing two or more chemical substances mixed with each other (mixed together).
• Formation of mixture never involves any chemical reaction and thus the chemical properties of the participating components remain unaffected.
• Both mixtures and solutions can be separated by physical methods.
• Mixtures are generally of two types: homogeneous and heterogeneous.
• Homogeneous mixtures are the one with the particles of the substances mixed together (no clumping of the particles happen) – example: air.
• Solutions are always homogenous mixtures: particles of one substance or the solute are mixed together with the particles of another substance or the solvent– Example- salt water.
• Heterogeneous mixtures are large aggregations (clumps) of the substances when mixed together – Example-emulsions like oil in water.
Thus, we can broadly conclude that all solutions are a mixture of a kind but not all mixtures are not a solution.