【Daily Question】March 7, 2016 – Participate to earn +2 wealth； +3 to 8 wealth for correct answers
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This post was last edited by zjp on 2016-3-8 08:03. To increase the popularity of the chemical analysis section, a \"One Question per Day\" campaign has been launched; it aims to foster active technical exchanges while also providing financial rewards to users. 【Daily Question】 (Single-choice question) The potassium permanganate method is used to determine the Ca2+ content in silicate samples. 0.5972 g of the sample was weighed. Under certain conditions, Ca2+ was precipitated as CaC2O4; the precipitate was filtered and washed. The washed CaC2O4 was dissolved in dilute sulfuric acid, and then titrated using a KMnO4 standard solution with a concentration of C(KMnO4) = 0.05052 mol/L. 25.62 mL of this solution was consumed in the titration. The mass fraction of Ca in the silicate was calculated accordingly. It is known that M(Ca) = 40 g/mol. A 24.19% B 21.67% C 48.38% D 74.60%. The correct answer is B. Reply with your answer in the comments; you will receive +2 wealth points for participating in the quiz. An additional +3 to +8 wealth points will be given if all answers are correct. Extra wealth points will also be awarded for thorough analyses and explanations of the questions or answers, or for detailed calculation processes. If your answer is correct and your analysis is accurate, it will be marked as the best reply (or the best assistance). Feel free to answer the questions.
The content of Ca2+ in silicate samples is determined using the potassium permanganate method. 0.5972 g of the sample was weighed. Under certain conditions, Ca2+ was precipitated as CaC2O4; the precipitate was filtered and washed. The washed CaC2O4 was dissolved in dilute sulfuric acid, and then titrated using a KMnO4 standard solution with a concentration of C(KMnO4) = 0.05052 mol/L. 25.62 mL of this solution was consumed in the titration. The mass fraction of Ca in the silicate was calculated accordingly (c). It is known that M(Ca) = 40 g/mol. A 24.19% B 21.67% C 48.38% D 74.60%
The content of Ca2+ in silicate samples is determined using the potassium permanganate method. 0.5972 g of the sample was weighed. Under certain conditions, Ca2+ was precipitated as CaC2O4; the precipitate was filtered and washed. The washed CaC2O4 was dissolved in dilute sulfuric acid, and then titrated using a KMnO4 standard solution with a concentration of C(KMnO4) = 0.05052 mol/L. 25.62 mL of this solution was required for the titration. The mass fraction of Ca in the silicate was calculated (b). It is known that M(Ca) = 40 g/mol. A 24.19% B 21.67% C 48.38% D 74.60%
The content of Ca2+ in silicate samples is determined using the potassium permanganate method. 0.5972 g of the sample was weighed. Under certain conditions, Ca2+ was precipitated as CaC2O4; the precipitate was filtered and washed. The washed CaC2O4 was dissolved in dilute sulfuric acid, and then titrated using a KMnO4 standard solution with a concentration of C(KMnO4) = 0.05052 mol/L. 25.62 mL of this solution was required for the titration. The mass fraction of Ca in the silicate was calculated (B). It is known that M(Ca) = 40 g/mol. A 24.19% B 21.67% C 48.38% D 74.60%
The content of Ca2+ in silicate samples is determined using the potassium permanganate method. 0.5972 g of the sample was weighed. Under certain conditions, Ca2+ was precipitated as CaC2O4; the precipitate was filtered and washed. The washed CaC2O4 was dissolved in dilute sulfuric acid, and then titrated using a KMnO4 standard solution with a concentration of C(KMnO4) = 0.05052 mol/L. 25.62 mL of this solution was required for the titration. The mass fraction of Ca in the silicate was calculated (B). It is known that M(Ca) = 40 g/mol. A 24.19% B 21.67% C 48.38% D 74.60%