【简答题】在锌湿法冶炼过程中,会产生大量铜镉渣(主要含有Zn、Cd、Fe、Cu等),直接丢弃会造成环境污染,也是资源浪费,以下为回收处理铜镉渣制备硫酸锌晶体的工业流程: 已知:硫酸锌晶体易溶于水,难溶于酒精。 (1)加入硫酸的目的 。 (2)硫酸不能溶出铜,加入锰粉是为了结合铁离子的变价来传递电子,将铜溶出,锰粉的主要成分为MnO 2 ,相关方程式为2Fe 3+ +Cu=2Fe 2+ +Cu 2+ 和 。 ...
【简答题】在Python中要调用SQLite数据库要引用包的语句是:
【单选题】《史记》中将老子、庄子、申不害和——放在一切作传记。
【单选题】Which fallacy is at work in the following? "Ms. Ng said to tell you I'm not reading enough. But I don't think you should worry. She's a teacher, so she has reading on her mind."
C.
circumstantial ad hominem
【单选题】绵阳市某天污各染物的日平均浓度如下:SO2:20ug/m3,NO2:50ug/m3,O3:150ug/m3(8h平均),PM10:80ug/m3,PM2.5:40ug/m3,CO:600 ug/m3,请问该日首要污染物是什么?
【简答题】同志说,“在改革中,我们始终坚持两条根本原则”( )。A. 以社会主义公有制为主体; B. 以按劳分配为主体; C. 计划调节和市场调节相结合; D. 共同富裕;
【单选题】A: Just look at the fog outside. B: ______.
A.
You should stay inside.
B.
Don't worry. The radio said that it should clear up by tomorrow.
C.
You should have listened to the weather forecast.
D.
I'm sorry, but I can't see anything.
【多选题】同志说,“在改革中,我们始终坚持两条根本原则” ( )