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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. Limiting reagent - Wikipedia

    en.wikipedia.org/wiki/Limiting_reagent

    If in fact 18 mol O 2 are present, there will be an excess of (18 - 11.25) = 6.75 mol of unreacted oxygen when all the benzene is consumed. Benzene is then the limiting reagent. This conclusion can be verified by comparing the mole ratio of O 2 and C 6 H 6 required by the balanced equation with the mole ratio actually present:

  4. 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.

  5. Law of multiple proportions - Wikipedia

    en.wikipedia.org/wiki/Law_of_multiple_proportions

    These compounds are known today as tin(II) oxide (SnO) and tin(IV) oxide (SnO 2). In Dalton's terminology, a "protoxide" is a molecule containing a single oxygen atom, and a "deutoxide" molecule has two. [3] [4] Tin oxides are actually crystals, they don't exist in molecular form. Example 2 — iron oxides: Dalton identified two oxides of iron ...

  6. Substitution reaction - Wikipedia

    en.wikipedia.org/wiki/Substitution_reaction

    The two reactions are named according tho their rate law, with S N 1 having a first-order rate law, and S N 2 having a second-order. [2] S N 1 reaction mechanism occurring through two steps. The S N 1 mechanism has two steps. In the first step, the leaving group departs, forming a carbocation (C +). In the second step, the nucleophilic reagent ...

  7. Faraday's laws of electrolysis - Wikipedia

    en.wikipedia.org/wiki/Faraday's_laws_of_electrolysis

    Second law [ edit ] Faraday discovered that when the same amount of electric current is passed through different electrolytes connected in series, the masses of the substances deposited or liberated at the electrodes are directly proportional to their respective chemical equivalent/ equivalent weight ( E ). [ 3 ]

  8. 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 ...

  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 ...