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

Latest Articles

  • 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.

  • The most expensive metal in the world

    Do you think the most expensive metal is gold? No! On earth there are more valuable metals. But we need to divide the value of metals that occur in nature, and metals - isotopes, which are obtained in special laboratories. Let’s look at natural metals first.

  • Chemistry of the sky

    Chemistry can teach us about the composition of celestial bodies and determine their age.

  • 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.

  • Ozone

    We breathe 24 hours a day, 7 days a week, consuming about 25 kg of air every day. It turns out that we practically predetermine our health by the air we breathe.



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Dipole Moment

The product of the distance separating opposite charges of equal magnitude of the charge, a measure of the polarity of a bond or molecule, a measured dipole moment refers to the dipole moment of an entire molecule.

Free Radical

A highly reactive chemical species carrying no charge and having a single unpaired electron in an orbital.

What are Compound Microscopes?

Most of the microscopes used today are compound. A compound microscope features two or more lenses. A hollow cylinder called the tube connects the two lenses.

The top lens, the one people look through, is called the eyepiece. The bottom lens is known as the objective lens. Below the two lenses is the stage, with the illuminator below that.

Overlap

The interaction of orbitals on different atoms in the same region of space.

Metallic Conduction

Conduction of electrical current through a metal or along a metallic surface.

Photochemical Oxidants

Photochemically produced oxidizing agents capable of causing damage to plants and animals.

Photochemical Smog

A brownish smog occurring in urban areas receiving large amounts of sunlight, caused by photochemical (light-induced) reactions among nitrogen oxides, hydrocarbons and other components of polluted air that produce photochemical oxidants.

 

Crystal Field Stabilization Energy

A measure of the net energy of stabilization gained by a metal ion's nonbonding d electrons as a result of complex formation.

Covalent Compounds

Compounds containing predominantly covalent bonds.

ytterbium

A rare metallic element found in gadolinite and forming compounds resembling those of yttrium. Symbol: Yb, at. wt.: 173.04, at. no.: 70, sp. gr.: 6.96. Cf."rare-earth element."