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【简答题】
试样中微量锰含量的测定常用 KMnO 4 比色法,称取试样 0.5000g ,经溶解,用 KIO 4 氧化为 KM nO 4 后 ,稀释至 500mL ,在波长 525nm 处测得吸光度为 0.400 。另取相近含量的锰浓度为 1.00*10 -4 mol/L 的 KMnO 4 标液,在同样条件下测得吸光度为 0.425 。已知两次测定均符合光吸收定律,问:试样中锰的质量分数是多少?( M Mn =54.94g/mol )
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A.
us to meet a few friends
B.
meeting a few friends
C.
a few friends to meet
D.
a few friends meeting
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our meeting a few friends
B.
us to meet a few friends
C.
a few friends to meet
D.
a few friends meeting
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A.
us to meet a few friends
B.
our meeting a few friends
C.
a few friends to meet
D.
a few friends meeting
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A.
mere
B.
much
C.
individual
D.
unique
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A.
when
B.
which
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that
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why
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简单罪状
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叙明罪状和空白罪状
C.
引证罪状
D.
空白罪状
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A.
that
B.
when
C.
on which
D.
on that
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