Dilution problem
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Why is the mass fraction of 1+4 phosphoric acid used in TOC 25%, rather than 26.4%? Please ask the expert to share the calculation process
Probably, an exact value isn’t necessary for this concentration; an approximate value will suffice. As for the calculation, please refer to junior high school knowledge: weight percentage concentration = weight of solute / weight of solution; P
This post was last edited by Yang Qing on 2020-12-14 08:18. If it is a volume fraction, it can be written as 20% (V/V); currently, the 1+4 format is commonly used in standards to represent volume fractions. Based on an analysis-grade phosphoric acid with a mass fraction of 85% and a density of 1.69, the mass percentage is calculated as 1.69*0.85/(1.69+4) = 25.25%, which can be approximated as 25%. P