Chemical change can be defined as the process that occurs when one substance is altered chemically, and it leads to the formation of a new substance after the change. When a chemical reaction takes place it cannot be reversed because it leads to the reorganization of atoms and it has a huge impact on the physical change of a substance. There are different types of chemical change including decomposition, double displacement, single displacement neutralization, precipitation, synthesis, combustion and many more.
There a few methods that one can use to detect whether a chemical change has taken place, because of the unique characteristics that they present when they occur, and they include a change of odor, whereby, when two physical substances come into contact with each other and a chemical change takes place there is likely to be a change in smell of the substance formed. When a chemical change takes place there is the change of temperatures where there might be loss of heat but in most chemical change reactions heat or energy is produced. Another characteristic of a chemical change is the change in color. For example when an iron nail comes into contact with water, the nail begins to rust and its color change from silver to reddish brown meaning that chemical change has taken place.
Another characteristic of chemical change is the formation of a precipitate or residue. When two substances are mixed together while one is soluble and the other substance is not, insoluble particles are likely to be seen. Other forms of chemical change may produce light or sound when they take place. An example is when magnesium ribbon comes into contact with oxygen, it produces a very bright flame. An example of a chemical change that produces sound is when salt is poured over a burning flame a cracking sound is produced. The production of gases and solids is also another characteristic of a chemical change. The gases produced appear in the form of bubbles as a result of the reaction. A solid maybe formed and it separates itself from the solution after the reaction.
There are many examples that can be used to explain chemical change including decomposition which takes place when one substance is exposed to certain conditions or comes to contact with another substance. An example is when leaves fall from a tree and they get exposed to excess water they start to decompose. Another example of a chemical change is cooking. When most of the food is cooked, it can not be reversed to the original substance it was in before cooking it, for example, when meat is cooked it changes the color. Combustion is also another example of chemical change whereby when combustion takes place the substances which were brought together for it to take place, rearrange to form a new substance. When wood is combusted the resulting product is usually ash. Another example of a chemical change is neutralization whereby a new substance is formed when it takes place. When an acid is mixed with a base the resulting product is salt and water.