【Active Participation for Joint Improvement 12.11-12.17】Participation: +2 to Wealth, +3~10 to Correct Wealth
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This post was last edited by zjp on 2015-12-10 08:12. Multiple-choice question: 2 points for active participation, 2 points for each correct answer, 10 points for selecting all answers correctly; no points for selecting incorrect answers, and no points for re-editing. Which of the following statements about chemical reagents is correct? A: The specifications of chemical reagents are generally classified according to the purity of the reagent and the level of impurities present. B: General chemical reagents refer to those of ultra-pure, analytical pure, and chemical pure grades. C: In China, the analytical pure grade as defined by reagent standards corresponds to grades C and D according to (IUPAC) standards. D: There are a wide variety of chemical reagents, and at present there is no unified standard for classifying them. Answer: ABD
The correct statements regarding chemical reagents are (A, B, D).
The correct statements regarding chemical reagents are (A, B, D).
The correct statements regarding chemical reagents are (ABD). A. The specifications of chemical reagents are generally classified according to the purity of the reagent and the level of impurities present. B. General-purpose chemical reagents refer to those of ultra-pure, analytical pure, and chemical pure grades. C. In China, the analytical pure grade as defined by reagent standards corresponds to grades C and D according to (IUPAC) standards. D. There are a wide variety of chemical reagents, and at present there is no unified classification method for them
The correct statements regarding chemical reagents are (ABD). A. The specifications of chemical reagents are generally classified according to the purity of the reagent and the level of impurities present. B. General-purpose chemical reagents refer to those of ultra-pure, analytical pure, and chemical pure grades. C. In China, the analytical pure grade as defined by reagent standards corresponds to grades C and D according to (IUPAC) standards. D. There are a wide variety of chemical reagents, and at present there is no unified classification method for them
The correct statements regarding chemical reagents are (ABD). A. The specifications of chemical reagents are generally classified according to the purity of the reagent and the level of impurities present. B. General-purpose chemical reagents refer to those of ultra-pure, analytical pure, and chemical pure grades. C. In China, the analytical pure grade as defined by reagent standards corresponds to grades C and D according to (IUPAC) standards. D. There are a wide variety of chemical reagents, and at present there is no unified classification method for them
The correct statements regarding chemical reagents are (ABD). A. The specifications of chemical reagents are generally classified according to the purity of the reagent and the level of impurities present. B. General-purpose chemical reagents refer to those of ultra-pure, analytical pure, and chemical pure grades. C. In China, the analytical pure grade as defined by reagent standards corresponds to grades C and D according to (IUPAC) standards. D. There are a wide variety of chemical reagents, and at present there is no unified classification method for them
The correct statements regarding chemical reagents are (AD). A: The specifications of chemical reagents are generally classified according to the purity of the reagent and the level of impurities present. B: General-purpose chemical reagents refer to those of ultra-pure, analytical pure, and chemical pure grades. C: In China, the analytical pure grade as defined by national reagent standards corresponds to grades C and D according to (IUPAC) standards. D: There are a wide variety of chemical reagents, and at present there is no unified classification method for them. The types of chemical reagents are numerous, and the standards for classifying and grading them vary from country to country. IUPAC classifies chemical reference materials as follows: Grade A: Atomic weight standards. Grade B: The reference material closest to Grade A. Grade C: Standard reagent with a purity of 100 ± 0.02%. Grade D: Standard reagent with a purity of 100 ± 0.05%. Grade E: Reagent whose purity is determined by comparison using Grade C or Grade D as references. In China, reagents equivalent to Grade C and Grade D according to IUPAC standards are commonly referred to as standard reagents.