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  2. List of unsolved problems in chemistry - Wikipedia

    en.wikipedia.org/wiki/List_of_unsolved_problems...

    RNA folding problem: Is it possible to accurately predict the secondary, tertiary and quaternary structure of a polyribonucleic acid sequence based on its sequence and environment? Protein design : Is it possible to design highly active enzymes de novo for any desired reaction?

  3. Conversion (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Conversion_(chemistry)

    Conversion and its related terms yield and selectivity are important terms in chemical reaction engineering.They are described as ratios of how much of a reactant has reacted (X — conversion, normally between zero and one), how much of a desired product was formed (Y — yield, normally also between zero and one) and how much desired product was formed in ratio to the undesired product(s) (S ...

  4. Equivalent (chemistry) - Wikipedia

    en.wikipedia.org/wiki/Equivalent_(chemistry)

    The solution has 1 mole or 1 equiv Na +, 1 mole or 2 equiv Ca 2+, and 3 mole or 3 equiv Cl −. An earlier definition, used especially for chemical elements , holds that an equivalent is the amount of a substance that will react with 1 g (0.035 oz) of hydrogen , 8 g (0.28 oz) of oxygen , or 35.5 g (1.25 oz) of chlorine —or that will displace ...

  5. Parts-per notation - Wikipedia

    en.wikipedia.org/wiki/Parts-per_notation

    The difference is quite significant when dealing with gases, and it is very important to specify which quantity is being used. For example, the conversion factor between a mass fraction of 1 ppb and a mole fraction of 1 ppb is about 4.7 for the greenhouse gas CFC-11 in air (Molar mass of CFC-11 / Mean molar mass of air = 137.368 / 28.97 = 4.74 ...

  6. Conversion of units - Wikipedia

    en.wikipedia.org/wiki/Conversion_of_units

    Conversion of units is the conversion of the unit of measurement in which a quantity is expressed, typically through a multiplicative conversion factor that changes the unit without changing the quantity. This is also often loosely taken to include replacement of a quantity with a corresponding quantity that describes the same physical property.

  7. Dalton (unit) - Wikipedia

    en.wikipedia.org/wiki/Dalton_(unit)

    The atomic mass constant, denoted m u, is defined identically, giving m u = ⁠ 1 / 12 ⁠ m(12 C) = 1 Da. [ 4 ] This unit is commonly used in physics and chemistry to express the mass of atomic-scale objects, such as atoms , molecules , and elementary particles , both for discrete instances and multiple types of ensemble averages.

  8. Reduction of nitro compounds - Wikipedia

    en.wikipedia.org/wiki/Reduction_of_nitro_compounds

    The reduction of nitro compounds are chemical reactions of wide interest in organic chemistry. The conversion can be effected by many reagents. The nitro group was one of the first functional groups to be reduced. Alkyl and aryl nitro compounds behave differently. Most useful is the reduction of aryl nitro compounds.

  9. Internal conversion - Wikipedia

    en.wikipedia.org/wiki/Internal_conversion

    Internal conversion is an atomic decay process where an excited nucleus interacts electromagnetically with one of the orbital electrons of an atom. This causes the electron to be emitted (ejected) from the atom. [1] [2] Thus, in internal conversion (often abbreviated IC), a high-energy electron is emitted from the excited atom, but not from the ...