Regarding the answer to question 9 in Issue 149 of Basic Chemical Engineering Knowledge
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9. Which of the following substances has an oxygen content of 50%? ________. A. CO2 B. CO C. SO2 D. H2O. The oxygen content is 50% only in option C; therefore, the correct answer is C, not B. The calculation is as follows: The atomic weight of S is 32, and the atomic weight of O is 16. The oxygen content is: 16X2/(16X2+32)X100% = 50%.
The one upstairs is correct: victory:
9. Which of the following substances has an oxygen content of 50%? ________. A. CO2 B. CO C. SO2 D. H2O The answer is B. Did the original poster give the wrong answer? How could it be B? It should be C instead.
What percentage? For the mass percentage, C was chosen, while for the molar percentage, B was selected.
Hehe, I also chose C, but the moderator’s answer was B. I’m not sure why. If it’s our mistake, I hope the moderator can provide an explanation; if it’s the moderator who made a mistake, I hope they will be more careful when creating questions in the future. There have been quite a few errors in the questions from recent issues as well. 1# GHJDSM
Support the original poster; I also chose C. The answer given by the moderator is likely incorrect; the oxygen content in CO is 57.1%, whereas it is 50% in SO2. The element contents don’t seem to specify the molar percentage.
Give some support; the original poster is a bit wrong
What was said on the fifth floor makes sense: it is necessary to distinguish between mass percentage and molar percentage； The meaning of the question is a bit unclear
That is, percentage contents include many types such as mass percentage, molar percentage, and so on. The title should be more specific and clear.