![](https://static.youtibao.com/asksite/comm/h5/images/m_q_title.png)
[单选题]
称取0.2354g含铜样品,用碘量法测定铜含量,如果析出的碘需要 25.00mLc(Na2S为0.l000mol/L的硫代硫酸钠标准滴定溶液进行滴定,则样品中铜的质量分数为〈 〉。己知 M(Cu)=63.546g/mol()
A.33.7%
B.33.74%
C.67.49%
D.67.5%
![](https://static.youtibao.com/asksite/comm/h5/images/m_q_a.png)
C、67.49%
![](https://static.youtibao.com/asksite/comm/h5/images/solist_ts.png)
A.33.7%
B.33.74%
C.67.49%
D.67.5%
C、67.49%
A.33.7%
B.33.74%
C.67.49%
D.67.5%
A.0.32g
B.0.64g
C.0.96g
D.1.28g
以K2Cr207法测定铁矿石中铁含量时,用0.02mol/LK2Cr207滴定。设试样含铁以Fe203(其摩尔质量为150.7g/mol)计约为50%,则试样称取量应为()。
A.0.1g左右
B.0.2g左右
C.1g左右
D.0.35g左右
A.0.1g左右
B.0.2g左右
C.1g左右
D.0.35g左右
A.1.57
B.3.65
C.2.57
D.4.57