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Elements with properties intermediate between metals and nonmetals: B, Al, Si, Ge, As, Sb, Te, Po, and At.

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  • 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...

  • Protein Design: Automated protein discovery and synthesis

    In this paper I describe (theoretically) the method(s) of automated protein discovery and synthesis.

  • 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.

  • 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.

  • 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.

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Semipermable Membrane

A thin partition between two solutions through which certain molecules can pass but others cannot.

Primary Standard

A substance of a known high degree of purity that undergoes one invariable reaction with the other reactant of interest.

Conjugated Double Bonds

Double bonds that are separated from each other by one single bond -C=C-C=C-.

Free Energy Change

The indicator of spontaneity of a process at constnt T and P. If delta-G is negative, the process is spontaneous.

Equilibrium or Chemical Equilibrium

A state of dynamic balance in which the rates of forward and reverse reactions are equal, the state of a system when neither forward or reverse reaction is thermodynamically favored.

Alkali Metals

Metals of Group IA (Na, K, Rb).

Covalent Compounds

Compounds containing predominantly covalent bonds.

Cathode Ray Tube

Closed glass tube containing a gas under low pressure, with electrodes near the ends and a luminescent screen at the end near the positive electrode, produces cathode rays when high voltage is applied.

Combination Reaction

Reaction in which two substances (elements or compounds) combine to form one compound.

Alkyl Group

A group of atoms derived from an alkane by the removal of one hydrogen atom.