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Pair of electrons residing on one atom and not shared by other atoms, unshared pair.

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Chemistry is a familiar school subject

Everyone liked to observe the reaction of reagents. But few know interesting facts about chemistry, which we will discuss in this article.

Standard Entropy

The absolute entropy of a substance in its standard state at 298 K.

Third Law of Thermodynamics

The entropy of a hypothetical pure, perfect, crystalline sustance at absolute zero temperature is zero.

Periodic Table of Elements

An arrangement of elements in order of increasing atomic numbers that also emphasizes periodicity.

Law of Conservation of Matter and Energy

The total amount of matter and energy available in the universe is fixed.

Flux

A substance added to react with the charge, or a product of its reduction, in metallurgy, usually added to lower a melting point.

yttrium

A rare trivalent metallic element, found in gadolinite and other minerals. Symbol: Y, at. wt.: 88.905, at. no.: 39, sp. gr.: 4.47. Cf."rare-earth element."

Yttrium has a silver-metallic luster and is relatively stable in air unless finely divided. Turnings of the metal, however, ignite in air if their temperature exceeds 400oC. Yttrium oxide is one of the most important compounds of yttrium and accounts for the largest use. It is widely used in making YVO4 europium, and Y2O3 europium phosphors to give the red color in color television tubes.

Aldehyde

Compound in which an alkyl or aryl group and a hydrogen atom are attached to a carbonyl group and a hydrogen atom are attached to a carbonyl group, general formula, O-R-C-H

 

Coke

An impure form of carbon obtained by destructive distillation of coal or petroleum.

Nonpolar Bond

Covalent bond in which electron density is symmetrically distributed.