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A degree of General Hardness (dGH or 'German degree' (°dH, deutsche Härte)) is defined as 10 mg/L CaO or 17.848 ppm. A Clark degree (°Clark) or English degree (°e or e) is defined as one grain (64.8 mg) of CaCO 3 per Imperial gallon (4.55 litres) of water, equivalent to 14.254 ppm.
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.
Water chemists measure water impurities in parts per million (ppm). For understandability, hardness ordinarily is expressed in grains of hardness per gallon of water (gpg). The two systems can be converted mathematically.
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]
As a unit 1 dKH is the same as 1 °dH which is equal to approximately 0.1786 mmol/L or 17.86 milligrams (mg) of calcium carbonate per litre of water, i.e. 17.86 ppm. [ citation needed ]
A new sex trend among college students is getting attention on TikTok − and it has doctors worried.. That trend is using honey packets, a controversial supplement marketed for sexual enhancement ...
Fluorescein aqueous solutions, diluted from 10,000 to 1 parts-per-million in intervals of 10 fold dilution. At 1 ppm the solution is a very pale yellow. At 1 ppm the solution is a very pale yellow. As the concentration increases the colour becomes a more vibrant yellow, then orange, with the final 10,000 ppm a deep red colour.
David R. Lide (ed), CRC Handbook of Chemistry and Physics, 84th Edition, online version. CRC Press. Boca Raton, Florida, 2003; Section 4, Properties of the Elements and Inorganic Compounds; Vapor Pressure of the Metallic Elements The equations reproduce the observed pressures to an accuracy of ±5% or better.