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  2. List of unsolved problems in chemistry - Wikipedia

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

    Protein folding problem: Is it possible to predict the secondary, tertiary and quaternary structure of a polypeptide sequence based solely on the sequence and environmental information? Inverse protein-folding problem: Is it possible to design a polypeptide sequence which will adopt a given structure under certain environmental conditions?

  3. Frustrated Lewis pair - Wikipedia

    en.wikipedia.org/wiki/Frustrated_Lewis_pair

    pcy 3 + b(c 6 f 5) 3 + c 2 h 4 → cy 3 p + ch 2 ch 2 b − (c 6 f 5) 3 For acid-base pairs to behave both nucleophilically and electrophilically at the same time offers a method for the ring-opening of cyclic ethers such as THF, 2,5-dihydrofuran, coumaran, and dioxane.

  4. Femtochemistry - Wikipedia

    en.wikipedia.org/wiki/Femtochemistry

    Femtochemistry is the area of physical chemistry that studies chemical reactions on extremely short timescales (approximately 10 −15 seconds or one femtosecond, hence the name) in order to study the very act of atoms within molecules (reactants) rearranging themselves to form new molecules (products).

  5. Sandwich compound - Wikipedia

    en.wikipedia.org/wiki/Sandwich_compound

    Examples of the double sandwich include V 2 2, [20] Ni 2 2 [21] and Cr 2 (pentalene) 2. Depicted at right is an example of a multimetallic sandwich compound, which has four palladium atoms joined in a chain sandwiched between two perylene units. [22] The counterions are bulky tetraarylborates.

  6. Physical chemistry - Wikipedia

    en.wikipedia.org/wiki/Physical_chemistry

    Physical chemistry, in contrast to chemical physics, is predominantly (but not always) a supra-molecular science, as the majority of the principles on which it was founded relate to the bulk rather than the molecular or atomic structure alone (for example, chemical equilibrium and colloids).

  7. Glossary of chemistry terms - Wikipedia

    en.wikipedia.org/wiki/Glossary_of_chemistry_terms

    Also acid ionization constant or acidity constant. A quantitative measure of the strength of an acid in solution expressed as an equilibrium constant for a chemical dissociation reaction in the context of acid-base reactions. It is often given as its base-10 cologarithm, p K a. acid–base extraction A chemical reaction in which chemical species are separated from other acids and bases. acid ...

  8. Law of multiple proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_multiple_proportions

    "Nitric acid" is 29.5% nitrogen and 70.5% oxygen, which means it has 320 g of oxygen for every 140 g of nitrogen. 80 g, 160 g, and 320 g form a ratio of 1:2:4. The formulas for these compounds are N 2 O, NO, and NO 2. [9] [10] The earliest definition of Dalton's observation appears in an 1807 chemistry encyclopedia:

  9. Rearrangement reaction - Wikipedia

    en.wikipedia.org/wiki/Rearrangement_reaction

    In organic chemistry, a rearrangement reaction is a broad class of organic reactions where the carbon skeleton of a molecule is rearranged to give a structural isomer of the original molecule. [1] Often a substituent moves from one atom to another atom in the same molecule, hence these reactions are usually intramolecular. In the example below ...