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  2. Empirical formula - Wikipedia

    en.wikipedia.org/wiki/Empirical_formula

    Glucose (C 6 H 12 O 6), ribose (C 5 H 10 O 5), Acetic acid (C 2 H 4 O 2), and formaldehyde (CH 2 O) all have different molecular formulas but the same empirical formula: CH 2 O.This is the actual molecular formula for formaldehyde, but acetic acid has double the number of atoms, ribose has five times the number of atoms, and glucose has six times the number of atoms.

  3. Formula unit - Wikipedia

    en.wikipedia.org/wiki/Formula_unit

    In most cases the formula representing a formula unit will also be an empirical formula, such as calcium carbonate (CaCO 3) or sodium chloride (NaCl), but it is not always the case. For example, the ionic compounds potassium persulfate ( K 2 S 2 O 8 ), mercury(I) nitrate Hg 2 (NO 3 ) 2 , and sodium peroxide Na 2 O 2 , have empirical formulas of ...

  4. Chemical formula - Wikipedia

    en.wikipedia.org/wiki/Chemical_formula

    An example of the difference is the empirical formula for glucose, which is CH 2 O (ratio 1:2:1), while its molecular formula is C 6 H 12 O 6 (number of atoms 6:12:6). For water, both formulae are H 2 O. A molecular formula provides more information about a molecule than its empirical formula, but is more difficult to establish.

  5. UNIFAC - Wikipedia

    en.wikipedia.org/wiki/UNIFAC

    In statistical thermodynamics, the UNIFAC method (UNIQUAC Functional-group Activity Coefficients) [1] is a semi-empirical system for the prediction of non-electrolyte activity in non-ideal mixtures. UNIFAC uses the functional groups present on the molecules that make up the liquid mixture to calculate activity coefficients. By using ...

  6. Combustion analysis - Wikipedia

    en.wikipedia.org/wiki/Combustion_analysis

    Combustion analysis is a method used in both organic chemistry and analytical chemistry to determine the elemental composition (more precisely empirical formula) of a pure organic compound by combusting the sample under conditions where the resulting combustion products can be quantitatively analyzed.

  7. Effective atomic number (compounds and mixtures) - Wikipedia

    en.wikipedia.org/wiki/Effective_atomic_number...

    The exponent of 2.94 relates to an empirical formula for the photoelectric process which incorporates a ‘constant’ of 2.64 × 10 −26, which is in fact not a constant but rather a function of the photon energy.

  8. Structural formula - Wikipedia

    en.wikipedia.org/wiki/Structural_formula

    Skeletal structural formula of Vitamin B 12.Many organic molecules are too complicated to be specified by a molecular formula.. The structural formula of a chemical compound is a graphic representation of the molecular structure (determined by structural chemistry methods), showing how the atoms are connected to one another. [1]

  9. Bicarbonate - Wikipedia

    en.wikipedia.org/wiki/Bicarbonate

    The bicarbonate ion (hydrogencarbonate ion) is an anion with the empirical formula HCO − 3 and a molecular mass of 61.01 daltons; it consists of one central carbon atom surrounded by three oxygen atoms in a trigonal planar arrangement, with a hydrogen atom attached to one of the oxygens. It is isoelectronic with nitric acid HNO 3.