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A small patch of photographic film worn on clothing to detect and measure accumulated incident ionizing radiation.

Latest Articles

  • 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.

  • 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?

  • 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.

  • 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.

  • 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.



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Natural Radioactivity

Spontaneous decomposition of an atom.

Absolute Entropy (of a substance)

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.

Primary Voltaic Cells

Voltaic cells that cannot be recharged, no further chemical reaction is possible once the reactants are consumed.

Acid

A substance that produces H+(aq) ions in aqueous solution. Strong acids ionize completely or almost completely in dilute aqueous solution. Weak acids ionize only slightly. Chemicals or substances having the property of an acid are said to be acidic.

PseudobinaryIonic Compounds

Compounds that contain more than two elements but are named like binary compounds.

Atom

The smallest particle of an element.

Molecule

The smallest particle of an element or compound capable of a stable, independent existence.

Detergent

A soap-like emulsifer that contains a sulfate, SO3 or a phosphate group instead of a carboxylate group.

Actinides

Elements 89 to 103 (between lawrencium and actinium) on the periodic table. Only the first four have been found in nature in appreciable amounts. The remainder have been produced synthetically.

Acetic Acid

CA3COOH, clear, colorless liquid, pungent odor. Boiling point 140C, flash point 54C (closed cup), autoignition temperature 38OC.