Explanation

Diamond is a non-metal with a high-density.

Graphite: A non-metal but has a lower density (~2.2 g/cm³).

Hydrogen: The lightest element with very low density (~0.000089 g/cm³).

Helium: Also very low density (~0.00018 g/cm³).

Diamond: A non-metal form of carbon with high density (~3.5 g/cm³).

Iron: A metal, so not a valid choice for a non-metal category.

Explanation

Nitrogen makes up about 78% of Earth's atmosphere,

It is the most abundant gas.

It is essential for plant growth as.

It is a key component of proteins and DNA.

Nitrogen is the chemical element with the symbol N and atomic number 7.

It was first discovered and isolated by Scottish physician Daniel Rutherford in 1772.

Explanation

• Isotopes of an element have the same atomic number (number of protons).
• It means they have the same chemical properties and are considered the same element.

Explanation

Nitrogen (N₂) makes up 78% of Earth's atmosphere and is not a pollutant.

NO₂ and SO₂ are major air pollutants from vehicles and industries.

Explanation

Helium is used in weather balloons.

Because it is lighter than air and non-flammable.

Explanation

Chemical energy is stored in a dry cell.

A dry cell is a device that converts chemical energy into electrical energy.

Chemical energy is the energy stored in the bonds of atoms and molecules. 

Explanation

Carbon monoxide (CO) is a poisonous gas that is emitted from the engine of an automobile.

The smoke released from the automobile is due to the combustion of fuels like petrol and diesel.

Explanation

Carbon dioxide is a colorless and non-flammable gas at normal temperature and pressure.

The bubbles in fizzy drinks are caused by carbon dioxide (CO2).

Soft drink manufacturers add fizz by dissolving carbon dioxide into the water at high pressures.

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Explanation

Biogas is produced under anaerobic conditions; the process is denominated as anaerobic digestion.

The major constituent of biogas is methane (55-70%), CO2 (30-45%) and some traces of gases such as H2S and ammonia.

Explanation

Cyclones are usually accompanied by high rainfall.

heavy showers mean: A period of heavy rain

Cyclones mean  ایک قسم کی طوفان

heavy showers  زیادہ بارش/  بھاری بارش

ND16-3-2023