Explanation

• Amino acids are the building blocks of proteins.
• Proteins are formed when amino acids join together by peptide bonds.
• Proteins are essential for growth, repair, and body functions.
• There are 20 standard amino acids used to make proteins.

Verified & Updated

Explanation

• The general formula for alkanes is CnH2n+2, where n is the number of carbon atoms in the molecule.
• This formula represents the saturated hydrocarbons, also known as paraffins.

Additional information:

• CnH2n is the general formula for alkenes.
• CnH2n+1 is the general formula for alcohols.

Last verified on 13-11-2026

Explanation

Water molecules are held together by hydrogen bonds,

It is a type of strong intermolecular force

Where the slightly positive hydrogen of one molecule attracts the slightly negative oxygen of another, creating a "sticky" network that gives water unique properties like surface tension.

Explanation

• Only about 2.5% or 0.025 (3%) of the water on Earth is freshwater, which is vital for human consumption, agriculture, and ecosystem health.
• The remaining 97.5% (97%) is saltwater, found in oceans, seas, and salt lakes.

Last verified on 02-11-2026

Explanation

• Water (H₂O) is a polar solvent due to its asymmetrical molecular structure.
• It results in a slightly positive charge on the hydrogen atoms.
• A slightly negative charge on the oxygen atom.

Last verified on 28-10-2026

Explanation

• Aeroplanes fly in the troposphere.
• It is the lowest layer of the Earth's atmosphere.
• It extending up to about 12 km (7.5 miles) above the Earth's surface.
• The troposphere is where weather occurs, and it's the layer where aircraft operate.
• It typically cruising at altitudes between 30,000 to 40,000 feet (9,100 to 12,200 meters).

Additional information:

• Stratosphere: Contains the ozone layer.
• Mesosphere: Most meteors burn up here.
• Thermosphere: Includes much of the ionosphere and auroras.

Last verified on 12-10-2026

Explanation

• Earth water coverage: 71%
• Land area: 29%
• Ocean water: 97% of total water
• Fresh water: 3% of total water
• Largest ocean: Pacific Ocean

Last verified on 10-04-2026

Explanation

The ozone layer is a region within the stratosphere, extending from about 15 to 30 km (9 to 19 miles) above the Earth's surface.

It contains a high concentration of ozone (O3), a molecule made up of three oxygen atoms. 

The ozone layer plays a crucial role in protecting the Earth from harmful ultraviolet (UV) radiation from the sun, particularly UV-C and UV-B rays.

Explanation

Amphoteric substances are those that can react with both acids and bases.

They can donate or accept protons (H+ ions), depending on the conditions.

Examples of amphoteric substances include water (H2O), amino acids, and certain metals like zinc and aluminum.

Explanation

Systematic errors are caused by faulty or improper functioning of instruments, or by a flaw in the experimental design.

These errors are consistent and repeatable, and can be identified and corrected.