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A group of atoms that represents a potential reaction site in an organic compound.

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Exothermic

Describes processes that release heat energy.

Electroplating

Plating a metal onto a (cathodic) surface by electrolysis.

Activation Energy

Amount of energy that must be absorbed by reactants in their ground states to reach the transition state so that a reaction can occur. In other words, activation energy is the minimum energy required for a chemical reaction to occur.

Strong Electrolyte

A substance that conducts electricity well in a dilute aqueous solution.

 

Osmotic Pressure

The hydrostatic pressure produced on the surface of a semipermable membrane by osmosis.

Octet Rule

Many representative elements attain at least a share of eight electrons in their valence shells when they form molecular or ionic compounds, there are some limitations.

Explosive limits

The range of concentrations over which a flammable vapour mixed with proper ratios of air will ignite or explode if a source of ignitions is provided.

Metallurgy

Refers to the overall processes by which metals are extracted from ores.

Calorie

The amount of heat required to raise the temperature of one gram of water from 14.5°C to 15.5°C. 1 calorie = 4.184 joules.

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.