Question

what is chemical reaction in science

Answer 1

chemical reaction refers to the transformation or modification of a chemical or multiple chemicals when treated with each other or subjected to some condition(s) to different type(s) having different molecular or ionic structure(s) and/or with different physical properties.

Answer 2

Chemical reaction is a process of forming new substance from another substances due to bonding of two different substances. Eg: Na + Cl → NaCl. There are two main things in a chemical reaction: Product and reactant. Product is a new substance formed. And, reactant is chemical due to which/on which reaction occurs. Chemical reactions occurs when some chemicals are reacted with other chemicals. A new substance is formed when the different chemicals are mixed/added together.

All the chemicals and Compounds which we see are formed due to process of chemical reaction. We know that, When two or more elements are bonded together, then the new substance compound is formed. The all compounds available naturally and artificially are formed due to bonding of two different elements i.e. Chemical reaction.

In a chemical reaction, the new substances are formed due to reaction/contact between two different substances. While chemical reaction, no atoms are destroyed nor new atoms are formed. Only, The atoms are rearranged in such a way that the the new substance is formed.

Chemical reactions are of 4 types: Synthesis, Decomposition, Single replacement , Double replacement.

• Synthesis reaction

A + B  →  AB  (Simple compounds formation)

• Decomposition reaction

AB  →  A + B  (Opposite of synthesis reaction)

• Single Displacement reaction

A + BC    →  AB + C  (Any of chemical is displaced)

• Double displacement reaction

AB + CD    →  AD + BC

Because of various chemical reactions done by scientists and development in chemistry has bought major changes in the world today. Everyday, scientists try to discover new chemicals, new compounds, new elements by doing complex chemical reactions. All the material used for making objects are made by doing chemical reactions only.

Examples of Chemical reaction:

• CH4 + 2O2 → CO2 + 2H2O
• C4H6O6 + NaHCO3 → NaC4H5O6+ H2O + CO2
• Na + Cl → NaCl
• 2 H2O → 2 H2 + O2
• HBr + NaOH → NaBr + H2O

What does a formula tell about substance:

• Because of formula of substance, we can get know about its components. And, the all mixtures of it.

• We can know about the proportion of specific substance. Because of which, it becomes very easy to research on the substance.

• Its chemical formula helps us to get know about the no. of atoms and molecules in it.

Example:

• Let's consider the example of Hydrochloric acid. We know the formula of Hydrochloric acid - H2SO4

• In this formula, there are elements called Sulphur, oxygen and hydrogen. Also, because of formula, we are able to understand it's all components and compounds in it.

• We can also know about it's Molar mass and molecular mass. We can also know about the proportion of the substance in it.