Physical and Chemical Changes
- The changes in which the physical properties and state of matter change but there is no change in its chemical properties are called physical changes.
- Water is in a liquid state and on heating, it turns into vapor state. This is an example of physical change.
- The changes in which the chemical properties and organization of a substance change are called chemical changes. A new substance is formed after a chemical change.
- An example of a chemical change is the carbon dioxide gas produced when coal is burnt.
- Other examples of chemical changes are curdling of milk, rusting of iron, etc.
- In any chemical reaction, substances are represented by atoms and symbols, the same is called a chemical equation.
- The substances participating in the chemical reaction are written to the left before the arrow marks are called actuators or reactants.
- The arrow marks indicate the direction of the reaction.
- The product on the right side of the arrow mark is the substance formed by the reaction.
- When a chemical changes in any substance, it differs from the original substance in chemical properties and organization. This phenomenon is called a chemical reaction.
- In a chemical reaction, products are formed from the possessors but the total mass of the substance remains the same.
- Combination reaction
A chemical reaction in which two or more reactants combine to form a single product is called a reaction.
2. Dissociation Reaction (Decompensation Reaction)
The reaction in which a reactant decomposes and forms two or more products is called a decomposition reaction.
The reactions in which decomposition occurs by the electric current are called electrolytic reactions.
The reaction in which decomposition occurs by heating.
The reaction in which the energy you get from the cut light is called.
3. Displacement Reaction
The reaction in which the atom or group of atoms present in one reactor is displaced by the atom or group of atoms of another reactant is called displacement reaction.
4. Double Displacement Reaction
In this type of reaction, atoms or groups of atoms of both reactants are displaced.
5. Exothermic Reactions
Reactions that emit/release energy are known as Exothermic reactions.
6. Endothermic Reaction
Reactions in which heat is absorbed are called endothermic reactions.
The addition of oxygen or removal of hydrogen is called an oxidation reaction.
Reactions in which the addition of hydrogen or removal of oxygen are called reduction reactions.
Based on the Exchange of Electrons
Reactions in which the element, atom, ion, or molecule release any number of electrons is called an oxidation reaction.
The reaction in which an element, atom, ion, or molecule accepts electron is called a reduction reaction.
Reactions that involve both oxidation and reduction are called redox reactions or oxidative reactions.
The substance that is oxidized is called the reducing agent and the substance that is reduced is called oxidizers.
Reductive electron donor reactant oxidizing electron
Any reactive substances which change the velocity of a chemical reaction but remain unchanged are called catalysts.
Substances that increase reaction velocity are called positive catalysts.
Substances that reduce the velocity of the reaction are called negative catalysts.
When a catalyst, reactant and product are in the same physical state in a chemical reaction, the catalyst is called a homogeneous catalyst.
When the physical state of the reactants and catalysts in a chemical reaction is different is called a Heterogeneous catalyst.