INTRODUCTION:

Chemicals are defined as any material with a certain composition. To put it another way, a chemical has always been composed of the same “substance.” Some chemicals, such as water, are found in nature. 

Other compounds, such as chlorine, are created in the same way (used for bleaching fabrics or in swimming pools). Chemicals are present in everything you consume, including the food you eat and the clothing you wear. You are, in reality, composed of a diverse range of chemicals.

WHAT IS A CHEMICAL REACTION?

A change in a chemical is referred to as a chemical reaction. A chemical reaction, in a broader sense, is the process through which one or even more chemicals change to form one or more new ones. Physical changes do not result in a change in substances, whereas chemical changes do. 

When water freezes into ice, this is an example of a physical transformation. Ice has distinct physical properties than water, yet it is still water. When you mix salt in a cup of water, another example comes to mind. While the salt might seem to vanish into the water, there is still water and salt present—nothing has changed into a wholly other component.

EXAMPLES OF CHEMICAL REACTION:

Iron Oxide (Iron + Oxygen)

Rust is iron oxide that can’t be converted back to iron or oxygen. It’s entirely new material. Reactants are the compounds on the left-hand side of the arrow in the equation (the substances that participate in a chemical reaction).

A product is the substance on the right-hand side of the arrow (a substance that results from a chemical reaction). It’s vital to note that no material is “lost” in the reaction in this scenario. You have iron and oxygen on one side of the equation, and you still have iron and oxygen on the other (now just combined into one chemical).

In this way, this example exemplifies what is known also as law of mass conservation. A general guideline about how something operates or occurs is referred to as a “law.” Due to a vast quantity of support for experimental testing and observation, this description is deemed quite credible. 

The law asserts that the outcomes of a chemical process have the same weight (“stuff”) as that of the reactants in the provided case. In other words, nothing is generated or destroyed as objects are reorganised.

INDICATORS TO DETECT A CHEMICAL CHANGE:

• You may detect bubbling or a difference in odour, which indicates that a gas is being produced. When baking soda and vinegar are combined, this is exactly what happens.
• When two clear solutions are combined and the mixture becomes hazy. A precipitate is formed when this happens.
• A shift in colour (like in our rust example).
• A temperature change or the production of light, as seen with fire.
• Although any of the above could indicate a chemical shift, physical changes can provide similar results. One approach to tell the two apart is to consider whether the new material could be physically divided into its constituent parts—in other words, if the material could “return” to its previous state. If it can’t, the problem is a chemical one.

PROPERTIES OF CHEMICALS:

Chemical attributes include flammability, toxicity, acidity, reactivity (of many types), and heat of combustion. Iron, for example, interacts with oxygen to form rust in the presence of moisture; chromium, but on the other hand, doesn’t really oxidise.

1. Flammability: A chemical’s flammability refers to its ability to burn or ignite, resulting in fire or combustion. The level of difficulty sufficient to induce a chemical to ignite is determined through fire testing. Materials are usually classified as highly flammable, flammable, or non-flammable.
2. Toxicity: Toxicity is defined as the amount of poison that, under certain conditions, produces toxic effects or causes harmful biological changes.
3. Acidity: The amount of acid in a material is described by this term. An acid is a substance that produces hydrogen ions in water & creates salts when it reacts with certain metals. The pH scale is often used to determine the acidity of a substance. On this scale, a pH of 7 indicates neutrality, whereas a pH little less than 7 to 0 indicates rising acidity.
4. Reactivity: The reactivity of an atom is determined by the number of electrons in its outermost shell. Noble gases have a low reactivity because they contain complete electron shells. Because they rapidly acquire an electron to form their outermost shell, halogens are highly reactive.
5. Heat of combustion: The amount of energy obtained from the combustion of a volume of natural gas is measured in British thermal units, and the heat of combustion (energy content) of natural gas is the quantity of energy obtained from the combustion of a volume of natural gas (Btu). The Btu content of natural gas is used to determine its worth.

CONCLUSION: 

By definition, a chemical is any substance made up of matter, which includes solid, liquids, and gases. Chemicals can be made up of a single ingredient or a combination of different chemicals. Water (H2O), for example, is a pure chemical because it contains the same components and combinations throughout its structure.

To distinguish them from mixtures, chemical substances are frequently referred to as ‘pure.’ Pure water is a common example of a chemical substance; it has the same characteristics and hydrogen-to-oxygen ratio whether it is extracted from a river or created in a laboratory.

Diamond (carbon), gold, salt (sodium chloride), and refined sugar are some of the other chemical compounds that are usually found in pure form (sucrose). In actuality, however, no substance is completely pure, so chemical purity is determined by the chemical’s intended purpose.