Keshu

Burning releases exothermic reaction

An exothermic reaction is a chemical or physical process that releases energy, typically as heat, light, or sound, into its surroundings.

A chemical bond is the attractive force that holds atoms, ions, or molecules together to form a compound.

An attractive force is a force that causes objects or particles to move toward each other.

Combustion is a rapid chemical reaction between a substance, called a fuel, and an oxidant, usually oxygen, that releases energy as heat and light, often with a flame.

An oxidant, also called an oxidizing agent, is a chemical substance that accepts electrons from another substance during a chemical reaction.

Group 7- the halogens

fluorine (F), chlorine (Cl), bromine (Br), iodine (I), and astatine (At).

The melting point of the halogens top to bottom decreases because as you move down, the atoms get larger and heavier, leading to stronger van der Waals force between the diatomic molecules, requiring more energy to melt or boil.

Van der Waals forces are weak, short-range electrostatic attractions between neutral atoms or molecules.

Electrostatic attraction is the force of attraction between two oppositely charged particles, like a positive and a negative charge.

The four fundamental forces are gravity, the electromagnetic force, the strong nuclear force, and the weak nuclear force.

1. What’s a Chemical Reaction?

A chemical reaction happens when one or more substances change into completely new ones. The particles of the reactants rearrange their atoms to form new bonds, creating products with different physical and chemical properties. For example:

2H2+O2→2H2O2H_2 + O_2 → 2H_2O2H2​+O2​→2H2​O

Here, hydrogen and oxygen (gases) react to form water (a liquid) — totally new properties!

2. Reactants & Products

• Reactants → the starting substances (what you begin with).

1. Only 2 research topic.

2. No mention of Santhosh Ji's work

3. Atomic research and respiration is not a specific topics

1. Elements and mixtures - create a post

atoms are the smallest building blocks of all substances around us

they combine to form molecules (like h2o= water, o2= oxygen gas

1. Physical changes require energy for processes like melting, or evaporation.

2. Physical changes often involve transitions between solid, liquid, gas

3. Solid-> liquid : ice melting

4. Liquid-> Gas: Water boiling

5. Solid-> Gas: Dry ice sublimation
   

6. Chemical changes produce substances with new chemical identities.