Define element, compound and mixture with examples.
An element is a pure substance that cannot be broken down into smaller substances. Each element’s atoms include the same atoms, which have identical structural and chemical properties.
There are 118 naturally occurring elements, of which 92 are found in nature and the remainder are created in laboratories.
In the year 1884 Berzelius presented a system for denoting elements through symbols. The shortest name of an element confined to usually a maximum of two alphabets is a symbol. Usually, the first alphabet of an element becomes its symbol but if two elements start with the same alphabet then the next alphabet is also taken for differentiation.
Some elements are represented by their Latin names
- Copper Cuprum Cu
- Silver Argentum Ag
- Tin Stannum Sn
A pure substance that is formed when two or more elements combine chemically in a definite proportion by mass is known as a compound.
Compounds are formed by the chemical combination of elements whose properties are entirely distinct from those of their parent elements. As a compound is a pure substance, its constituents cannot be separated through physical means.
The most essential property of a compound is its constant mass ratio. Hydrogen Peroxide [H2O2] is an example of a compound. Which is applied to the skin as an antiseptic to prevent infection from minor cuts?
In hydrogen peroxide, the ratio of hydrogen to oxygen is always 2:2. Changing this ratio will yield an entirely different compound.
Representation of compounds
The constituents of a compound are represented through a chemical formula. The formula shows the elements which chemically combined to form that particular compound.
Hydrogen Peroxide H2O2
Methane [Natural Gas] CH4
A physical combination of two or more substances in any ratio is known as a mixture. It is an impure substance.
A mixture is obtained when two or more elements or compounds are mixed in any ratio such that their constituents retain their original properties. The constituents of a mixture can be separated through various physical methods e.g Distillation, Filtration, and Crystallization.
Components of a mixture
A mixture is composed of two components namely;
The minor component in a solution that is dissolved in the solvent is known as solute.
The major component in a solution that dissolves the solute is known as a solvent. It is also known as a dissolving medium.
- Salt in water
- Petrol in water
Types of mixtures
Following are the types of mixtures
1. Homogeneous mixture
2. Heterogeneous mixture
The type of mixture in which the composition is uniform throughout the mixture. A homogeneous mixture exists in only one phase. E.g salt in water, glucose in water.
The type of mixture in which the composition is not uniform is known as a heterogeneous mixture. E.g petrol in water, sand in water.
Related Chemistry pdf‘s