Physical Change and Chemical Change

Types and Example of Physical Change and Chemical Change

In science, there are two major changes broadly. The first is the physical change, and the second is chemical change. Today we will talk about these two changes in detail.

Physical Changes - Physical changes are those changes which affect the form of a chemical substance, but not it's chemical composition. Physical changes separate the mixtures into their component compounds, but physical changes cannot separate compounds into chemical elements, or into the simple compounds. When objects or substances undergo a change that doesn't change their chemical composition, the physical changes occur. The concept of the physical changes is totally opposite from the concept of the chemical changes in which the composition of a substance changes into the new substance, either by combining or breaking. Physical changes are reversible changes. In physical changes, reactants can change into the products and the products can change into the reactants. Just like, dissolved salt in water can recover by the process of evaporation. The process of Physical changes are the physical properties of substance like the melting, transition to the gas, change of the strength, change of durability, changes to crystal form, textural change, shape, size, color, volume, and density. Physical change is a process of tempering steel from a knife blade. A steel blank is heated and hammered again and again which increase flexibility, hardness, and ability to maintain a sharp edge of the steel.
In many physical changes, the involvement of rearrangement of atoms in the formation of crystals is noticed. Physical changes are reversible, and the chemical changes are irreversible, but this is not the criteria to classify these two changes. Chemical changes can recognize from such indications like odor, color change, or production of the gas.

Example Of Physical Changes - There are several examples of Physical changes which are given below.

Heating and Cooling - Many elements and compounds change their state solid to liquid and liquid to gas when heated and do the reverse when cooled. Some substances like Iodine and Carbon dioxide go directly from solid to gas by a process which is called sublimation.

Magnetism - With the help of physical changes, Ferro-magnetic materials can become magnets, and can again become Ferro-magnetic because this process is reversible which does not affect the chemical composition.

Crystallization - Many elements and compounds can make the crystal. Like carbon which has several forms like diamond, graphite, graphene, and fullerenes including buckminsterfullerene. Crystal has a major of the physical properties like strength and ductility in the metals. Crystal type, crystal shape, and crystal size can be changed by hammering, rolling, and by the heat.

Mixtures - mixtures of such substances which are not soluble get separated from the process of physical changes. The mixture has different properties from the individual components. Such as mixture of sand and water which is used to make sandcastles. Sandcastles do not behave like both sand and water. By using surface tension which is a physical property, sandcastles behave in a different way.

Solutions - Some of the solutions and compounds like sugar can be separated by the process of evaporation. Some other mixtures and liquids like low molecular weight alcohols get separation by the process of fractional distillation.

Alloys - Alloying is the process to mix the different metal elements. The Alloy of Copper and Zinc is Brass. To separate the different metal elements from an alloy is almost impossible. Making an alloy is the example of such physical changes which is irreversible. Mercury is one of the materials which can get separated by melting the alloy and boiling the mercury.

Chemical Change - When a substance combines with the other one to produce a new product, chemical changes occur. The process to make a new product is called chemical synthesis or chemical decomposition. In general, this process is called the Chemical Reaction. Some chemical reactions produce heat, these reactions are called the exothermic reactions, and some chemical reactions absorb the heat which is called endothermic reactions.

In chemistry, chemical changes are very important. The atoms are rearranged, and new products are generated with the help of energy change in a chemical reaction. Chemical changes are generally irreversible. It means the product which made under a chemical reaction can't turn into the reactant again. Such an example of this is the reaction between sodium and water which made sodium hydroxide and hydrogen. Once Sodium hydroxide and hydrogen are made, they can't turn into the Sodium and water again.

Types Of Chemical Changes - There are three types of chemical changes about which are given below.

1. Inorganic Chemical changes - Inorganic chemical changes are such changes in which carbon doesn't involve. Inorganic chemical changes take place in laboratories, and on a large scale in heavy industries. The major examples of inorganic chemical changes are neutralization, oxidization including combustion, redox reactions.

2. Organic Chemical Changes - Organic chemical changes are such the changes in which carbon involve. Organic chemical changes are used in the manufacturing of oils and their outputs. Apart from the oil manufacturing industry, organic chemical changes are useful in the manufacturing industries of pharmaceuticals, paints, detergents, cosmetics, and fuels, etc. The major example of the organic chemical changes is to the crack heavy hydrocarbons at an oil refinery to produce the Gasoline in the larger number from the crude oil because the gasoline has more demand as compared to the heavy hydrogen. Apart from this, other chemical reactions are methylation, condensation reactions, polymerization, halogenation, etc.

3. Biochemical Changes - Biochemistry is useful for the chemistry for the growth and activity of living organisms. Biochemical Reactions are controlled by the complex proteins which are called enzymes and are moderated and limited by the hormones. Biochemistry is so highly complex that still no one fully understood this. Decomposition of organic material also comes in the range of Biochemistry, but the growth and activity of fungi, bacteria and the other micro-organism only come in the range of biochemistry.

There are a lot of examples of Biochemistry like Photosynthesis. Photosynthesis is a process in which carbon dioxide and water are changed into sugars and oxygen by plants with the help of Sunlight. Digestion is such a process in which energy-rich materials are used by the organisms for their growth and movement. Krebs cycle is used to liberate energy from the reserve stores. Protein synthesis is such a process which is controlled by RNA. This process enables organisms to grow.

Evidence of a Chemical Change - There is such evidence which gives a clear indication of the chemical reaction.

1. The change in the odor of the substance shows the chemical change.
2. The change in the color of substance shows the chemical change.
3. The Change in heat and temperature show the chemical change.
4. The change in state of substance shows the chemical change.
5. Formation of gases also shows the chemical change.
6. Formation of a precipitate shows the chemical change.
7. The decomposition of organic matter like rotting food shows the chemical change.

Examples of Chemical Change - Rusting on iron, milk goes sour, the metabolism of food in the body, burning of wood, cooking an egg, rotting bananas, are some basic examples of Chemical Changes.