Railway Science (Chemistry-Miscellaneous) (Part-II)

Carbon (C) - It occurs normally as Anthracite, Graphite, Diamond. Other elements: Lithium (Li) - Lightest metal in the periodic table, used in batteries. Phosphorus (P) - It is mostly used in plant fertilization, chemical pesticides. Argon (Ar) - It is colorless, odorless gas and commonly used in inert shielding gas.

Sublimable substance: Solid that can go directly from the solid state to the gaseous state without changing into liquid. Examples - Iodine, Camphor, Dry ice, Ammonium chloride, Anthracene and Naphthalene.

Methane is a pure substance because it always has the same composition. However, it is not an element because it can be broken down into simpler substances - carbon and hydrogen. Copper, silver, gold, water, glucose are some examples of pure substances.

The intermolecular / interatomic force of attraction is maximum in solids. Due to this, the molecules of solids are closely packed.

Copper (Cu) can exhibit two common oxidation states: +1 and +2. Therefore, it has variable valency. In its +1 oxidation state, copper loses one electron to achieve a stable configuration, and its valency is +1.
This is seen in compounds like cuprous oxide (Cu₂O). In its +2 oxidation state, copper loses two electrons to achieve stability, and its valency is +2.
This is seen in compounds like copper oxide (CuO) and copper sulfate (CuSO₄). The term ‘cuprous’ is used to refer to copper in its +1 oxidation state.

Nuclear energy - a form of energy released from the nucleus, made up of protons and neutrons. It originates from the splitting of Uranium atoms (a process called fission). This generates heat to produce steam, which is used by a turbine generator to generate electricity.
Types of Energy: Thermal Energy, Mechanical energy, Electrical energy, Kinetic energy, Mechanical energy, Chemical energy, Gravitational energy, Radiant energy.

Solid CO₂ is used extensively in vaccine cooling, food chilling and freezing, blood and tissue sample preservation, heat treating of metals, and even to create special effects such as fog for events or stage productions.

Solids have strong forces holding their particles together tightly, so they keep their shape. Liquids and gasses have weaker forces, letting their particles move more freely, so they take the shape of their container. The property of a substance in which its volume decreases under high pressure and it is called Compressibility, not size.

Calcium chloride (CaCl₂) is a hygroscopic salt, meaning it readily absorbs moisture from its surroundings. This makes it ideal for drying gasses in humid conditions. Calcium hydroxide Ca(OH)₂ , is obtained by the action of water on calcium oxide.
Sodium chloride (NaCl) is an essential compound used to absorb and transport nutrients. Sodium hydroxide (NaOH) is used to produce soaps, rayon, paper, products that explode, dyes, and petroleum products.