Explanation

• Chemical energy is the energy stored in the bonds between atoms and molecules.
• It is released or absorbed during chemical reactions.
• Found in substances like food, fuel, and batteries.
• It is a form of potential energy stored in chemical bonds.
• It changes into other forms like heat or light when reactions occur.

Last verified on 08-06-2026

Explanation

• Sublimation is the direct transition of a solid into a gas without passing through the liquid phase.

Additional information:

Some common sublimating substances:

• Dry ice (CO₂) – solid → gas
• Iodine crystals – solid → violet gas
• Camphor – solid → vapor
• Naphthalene (mothballs) – solid → gas
• Ammonium chloride – solid → gas

Last verified on 13-03-2026

Explanation

• The hardest substance in the world is diamond.
• Its hardness is due to the strong covalent bonding between its carbon atoms.
• This making it the most resistant to scratching.

Additional information:

• Category: Native minerals
• Cleavage: 111 (perfect in four directions)
• Crystal class: Hexoctahedral (m3m); H-M symbol: (4/m 3 2/m)
• Crystal habit: Octahedral
• Crystal system: Cubic
• Dana classification: 1.3.6.1
• Density: 3.5–3.53 g/cm3 3500–3530 kg/m3

Last verified on 07-06-2026

Explanation

• The chemical formula for water is H₂O.

Atomic masses:

• Hydrogen (H) = 1 amu each → 2 × 1 = 2 amu
• Oxygen (O) = 16 amu

Total molecular mass = 2 (from H) + 16 (from O) = 18 amu.

Last verified on 07-06-2026

Explanation

• The law that states mass can neither be created nor destroyed is the Law of Conservation of Mass.
• This law states that mass remains constant in a chemical reaction.
• Matter cannot be created or destroyed, only transformed.

Last verified on 02-04-2026