Mass defect refers to the difference between the actual mass of an atomic nucleus and the sum of the masses of its constituent protons and neutrons, due to the conversion of mass into energy during nuclear binding.

The energy released in nuclear fusion comes from the conversion of mass into energy. When light nuclei (such as hydrogen isotopes) fuse to form a heavier nucleus (like helium), a small amount of mass is lost and converted into energy.

A periodic property is a characteristic of elements that repeats at regular intervals when elements are arranged by increasing atomic number. Example: Atomic radius decreases across a period and increases down a group.

Mass number is not a periodic property, as it doesn't follow a regular trend across the periodic table.

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Electronegativity is the ability of an atom to attract electrons towards itself in a chemical bond.

In Group 1 of the long periodic table, electronegativity decreases from top to bottom as the atomic size increases, making it harder for the nucleus to attract bonding electrons.

The energy responsible for the chemical reactions during electrolysis is electrical energy.

At the Cathode (Reduction):

2H⁺ + 2e^- → H₂ (Hydrogen Gas)

Hydrogen ions gain electrons to form hydrogen gas.

At the Anode (Oxidation):

H₂O → O₂ + 4H⁺ + 4e^-

Water molecules lose electrons to form oxygen gas and hydrogen ions.

SO₃ (Contact Process):

2SO₂ (g) + O₂ (g) → 2SO₃ (g)

Conditions:

Catalyst: Vanadium pentoxide (V₂O₅)

Temperature: 450°C

Pressure: 1-2 atm

Preparation of H₂SO₄ from SO₃ :

Sulfur trioxide (SO₃) is absorbed in concentrated sulfuric acid (H₂SO₄) to form oleum (H₂S₂O₇) which is then diluted with water to form sulfuric acid.

2SO₃ (g) +  H₂SO₄ (l) → H₂S₂O₇ (Oleum)

H₂S₂O₇ (l) + H₂O (l)  → 2H₂SO₄ (l)

The addition of hydrogen to acetylene (ethyne) produces ethane. The reaction occurs in the presence of a nickel at 300° C.

C₂H₂ (g) + 2H₂ → C₂H₆ (g)

One Use of LPG:

LPG (Liquefied Petroleum Gas) is commonly used as a cooking fuel in households.

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Ethanol (CH₃CH₂OH) is converted to ethene (CH₂=CH₂) by dehydration using concentrated sulfuric acid as a catalyst at 170ºC.

CH₃CH₂OH → CH₂=CH₂ + H₂O

Biodegradation of Protein:

Proteins are biodegraded in nature by enzymes into amino acids, which are further broken down by bacteria into simpler compounds like carbon dioxide and water.

The main component of biogas is methane (CH₄), which typically makes up about 50-75% of the gas.

The SI unit of electric charge is the coulomb (C).

There are 8 elements in the third period of the long periodic table.

The radioactive ray that is not made up of particles is gamma rays (γ-rays). Gamma rays are electromagnetic waves, not particles.

The industrial source of Compressed Natural Gas (CNG) is natural gas, primarily composed of methane.

The absolute scale of temperature is known as the Kelvin scale. On this scale, temperature is measured in Kelvin (K), and it starts from absolute zero, which is the theoretical lowest possible temperature where molecular motion ceases. Absolute zero is defined as 0 K, equivalent to -273.15°C.

The two advantages of AC over DC

1. AC is easy and cheaper to generate than DC.
2. Power loss in AC is less as compared to DC during transmission.