Star InactiveStar InactiveStar InactiveStar InactiveStar Inactive
 

The increase in the entropy of a substance as it goes from a perfectly ordered crystalline form at 0 °K (where its entropy is zero) to the temperature in question.

Entropy is a measure of the “dilution” of thermal energy.

Latest Articles

  • Varieties of garnet minerals

    The most famous type of garnet stone is pyrope (flaming). This is the "oldest of garnets", with a dense red color, similar to the grain of an edible garnet. Pyrope has a variety called rhodolite - a stone of dense pink or pink-purple color, which sometimes has the alexandrite effect and is used in...

  • Why do copper products change color, and what is the name of the process?

    Probably, every person wants to know, why over time the copper turns green and becomes bloomed. This is easy to explain: that film is called patina.

  • Interesting facts about metals

    Metals have been used by people since ancient times. All the time the process of obtaining them was improved, useful alloys of various metals appeared. Let’s look at interesting facts about metals.

  • Gas of rotten eggs

    If you happen to break a rotten egg, then you know the smell of hydrogen sulfide, because the stench of the spoiled egg depends on of its presence in rotting protein substances.

  • Diamonds Are Forever

    Diamonds are still a girl's best friend, right? We love the shiny gems. They are the most popular rocks sold today. But what exactly are they, anyway? Where do they come from? What else are they used for?



Most Popular

Standard Reaction

A reaction in which the numbers of moles of reactants shown in the balanced equation, all in their standard states, are completely converted to the numbers of moles of products shown in the balanced equation, also sall at their standard state.

Monoprotic Acid

Acid that can form only one hydronium ion per molecule, may be strong or weak. Acid that contains one ionizable hydrogen atom per formula unit.

Hund's Rule

All orbitals of a given sublevel must be occupied by single electrons before pairing begins.

Binary Acid

A binary compound in which H is bonded to one or more of the more electronegative nonmetals.

Atmosphere

A unit of pressure, the pressure that will support a column of mercury 760 mm high at 0 °C.

Barometer

A device for measuring pressure.

Spectator Ions

Ions in a solution that do not participate in a chemical reaction.

Hard Water

Water containing Fe3+, Ca2+, and Mg2+ ions, which forms precipates with soap.

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.

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.