【Daily Question】9.27 Reply +2； For +3 to 8, a Mid-Autumn Festival red envelope is issued
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This post was last edited by zjp on 2015-9-28 at 11:38. First of all, wish everyone a happy Mid-Autumn Festival! Red envelopes will be given for replies today. To increase the popularity of the chemical analysis section, the previous 【Weekly Topic】 activity has been replaced with a 【Daily Question】 activity; this helps to foster an active atmosphere for technical exchanges while also providing rewards in the form of financial incentives to users. 【Daily Question】 (Single-choice question) Now, we want to prepare 1 liter of a 0.01000 mol/L K2Cr2O7 solution, (M=294.2 g/mol). The accuracy of the analytical balance used is ±0.1mg. If the required relative error is ±0.2%, then the weighing of K2Cr2O7 should be accurate to ( ). A. 0.1g B. 0.01g C. 0.001g D. 0.0001g Please reply with your answer in the comments; answering correctly earns you +2 wealth points. Getting all answers right grants an additional +3 to +8 wealth points. Those who provide a thorough analysis and explanation of the questions or answers (including detailed calculation processes) will receive extra wealth points as a reward. 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. Note: We will close this post after 24 hours, and at that time we will announce the best reply (the best assistance), as well as the answer and explanation.
I now wish to prepare 1 liter of a 0.01000 mol/L K2Cr2O7 solution, (M=294.2 g/mol). The accuracy of the analytical balance used is ±0.1mg. If the required relative error is ±0.2%, then K2Cr2O7 should be weighed to an accuracy of (D.0.0001g). A.0.1g B.0.01g C.0.001g D.0.0001g
I now wish to prepare 1 liter of a 0.01000 mol/L K2Cr2O7 solution, (M=294.2 g/mol). The accuracy of the analytical balance used is ±0.1mg. If the required relative error is ±0.2%, then K2Cr2O7 should be weighed to (D).
I now wish to prepare 1 liter of a 0.01000 mol/L K2Cr2O7 solution, (M=294.2 g/mol). The accuracy of the analytical balance used is ±0.1mg. If the required relative error is ±0.2%, then K2Cr2O7 should be weighed to (C).
Happy Mid-Autumn Festival! ! ! ! I now wish to prepare 1 liter of a 0.01000 mol/L K2Cr2O7 solution, (M=294.2 g/mol). The accuracy of the analytical balance used is ±0.1mg. If the required relative error is ±0.2%, then K2Cr2O7 should be weighed to (D). A.0.1g B.0.01g C.0.001g D.0.0001g
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b...................
C.0.001g. . . . . . . . . . . . . . . . . . . . .