about science chemical reaction
Answers
Answer:
A chemical reaction is a chemical change in which matter changes into a new substance or substances, it is often accompanied by external indicators and characteristics.
Explanation:
Mercury [II] oxide on heating turns silvery.
Chemical reaction is a process of forming new substance from another substances due to bonding of two different substances. This process 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