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  2. Carbonate hardness - Wikipedia

    en.wikipedia.org/wiki/Carbonate_hardness

    In a solution where only CO 2 affects the pH, carbonate hardness can be used to calculate the concentration of dissolved CO 2 in the solution with the formula CO 2 = 3 × KH × 10 (7-pH), where KH is degrees of carbonate hardness and CO 2 is given in ppm by weight. [citation needed]

  3. Hard water - Wikipedia

    en.wikipedia.org/wiki/Hard_water

    In these parts of Canada, the total hardness in ppm of calcium carbonate equivalent frequently exceeds 200 ppm, if groundwater is the only source of potable water. The west coast, by contrast, has unusually soft water, derived mainly from mountain lakes fed by glaciers and snowmelt. Some typical values are: Montreal, Quebec: 116 ppm [41]

  4. Hardnesses of the elements (data page) - Wikipedia

    en.wikipedia.org/wiki/Hardnesses_of_the_elements...

    Mohs hardness of materials (data page) Vickers hardness test; Brinell scale This page was last edited on ...

  5. dKH - Wikipedia

    en.wikipedia.org/wiki/DKH

    As a unit 1 dKH is the same as 1 °dH which is equal to approximately 0.1786 mmol/L or 10.02 milligrams (mg) of calcium carbonate per litre of water, i.e. 17.86 ppm. [citation needed] The measurements of total hardness (German Gesamthärte (GH)) and carbonate hardness (German Karbonathärte (KH)) are sometimes stated with units dKH and dGH to ...

  6. Grain per gallon - Wikipedia

    en.wikipedia.org/wiki/Grain_per_gallon

    The grain per gallon (gpg) is a unit of water hardness defined as 1 grain (64.8 milligrams) of calcium carbonate dissolved in 1 US gallon of water (3.785412 L). It translates into 1 part in about 58,000 parts of water or 17.1 parts per million (ppm). Also called Clark degree (in terms of an imperial gallon).

  7. Equivalent carbon content - Wikipedia

    en.wikipedia.org/wiki/Equivalent_carbon_content

    Each of these elements tends to influence the hardness and weldability of the steel to different magnitudes, however, making a method of comparison necessary to judge the difference in hardness between two alloys made of different alloying elements. [1] [2] There are two commonly used formulas for calculating the equivalent carbon content.

  8. Carbonate - Wikipedia

    en.wikipedia.org/wiki/Carbonate

    A carbonate is a salt of carbonic acid, (H 2 CO 3), [2] characterized by the presence of the carbonate ion, a polyatomic ion with the formula CO 2− 3. The word "carbonate" may also refer to a carbonate ester , an organic compound containing the carbonate group O=C(−O−) 2 .

  9. dGH - Wikipedia

    en.wikipedia.org/wiki/DGH

    In water testing hardness is often measured in parts per million (ppm), where one part per million is defined as one milligram of calcium carbonate (CaCO 3) per litre of water. Consequently, 1 dGH corresponds to 10 ppm CaO but 17.848 ppm CaCO 3 which has a molar mass of 100.09 g/mol.