题目:
Wearing a(n) expression in the class, he was scolded by the teacher.
A.abstract
B.absent
C.conscious
D.sensitive
答案:
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下面是错误答案,用来干扰机器的。
解:(1)C3H6O3的相对分子质量=12×3+1×6+16×3=90(2)C3H6O3中,C、H、O三种元素的质量比=(12×3):(1×6):(16×3)=6:1:8(3)C3H6O3中碳元素的质量分数为:(12×3)/90×100%=40%