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  2. R-factor (crystallography) - Wikipedia

    en.wikipedia.org/wiki/R-factor_(crystallography)

    Small molecules (up to ca. 1000 atoms) usually form better-ordered crystals than large molecules, and thus it is possible to attain lower R-factors. In the Cambridge Structural Database of small-molecule structures, more than 95% of the 500,000+ crystals have an R-factor lower than 0.15, and 9.5% have an R-factor lower than 0.03.

  3. Past paper - Wikipedia

    en.wikipedia.org/wiki/Past_paper

    For example, UPSC papers in India, SAT papers in U.S. and GCSE and A level papers in UK are being sold, as well as other exams worldwide. Previous year question (PYQ) papers are to assess student's brilliancy and capabilities. Students who are preparing for competition exams generally look for past papers.

  4. List of unsolved problems in chemistry - Wikipedia

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

    This article or section possibly contains synthesis of material that does not verifiably mention or relate to the main topic. Relevant discussion may be found on the talk page . ( June 2021 ) ( Learn how and when to remove this message )

  5. Acetyl group - Wikipedia

    en.wikipedia.org/wiki/Acetyl_group

    The carbonyl center of an acyl radical has one non-bonded electron with which it forms a chemical bond to the remainder (denoted with the letter R) of the molecule. The acetyl moiety is a component of many organic compounds , including acetic acid , the neurotransmitter acetylcholine , acetyl-CoA , acetylcysteine , acetaminophen (also known as ...

  6. Chemical biology - Wikipedia

    en.wikipedia.org/wiki/Chemical_biology

    An overview of the different components included in the field of chemical biology. Chemical biology is a scientific discipline between the fields of chemistry and biology.The discipline involves the application of chemical techniques, analysis, and often small molecules produced through synthetic chemistry, to the study and manipulation of biological systems. [1]

  7. Biochemistry - Wikipedia

    en.wikipedia.org/wiki/Biochemistry

    Biochemistry or biological chemistry is the study of chemical processes within and relating to living organisms. [1] A sub-discipline of both chemistry and biology, biochemistry may be divided into three fields: structural biology, enzymology, and metabolism. Over the last decades of the 20th century, biochemistry has become successful at ...

  8. Reaction rate constant - Wikipedia

    en.wikipedia.org/wiki/Reaction_rate_constant

    where A and B are reactants C is a product a, b, and c are stoichiometric coefficients,. the reaction rate is often found to have the form: = [] [] Here ⁠ ⁠ is the reaction rate constant that depends on temperature, and [A] and [B] are the molar concentrations of substances A and B in moles per unit volume of solution, assuming the reaction is taking place throughout the volume of the ...

  9. 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 ...

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