【判断题】古法印制的照片在阳光下会变色,因此要避光保存。()
【简答题】饱和一元醛的通式为( )或( ),乙醛与银氨溶液反应的化学方程式为( ). 每mol醛基参加反应,有( )mol银生成。
【单选题】公元前 501 年,自己制作了一部“竹刑”的郑国人是 ( )?
【简答题】. New economy online People are talking about the “new economy”. It’s very different from the “old economy”. In the old economy, people travel to walk. They buy things in stores. They use the post off...
【简答题】What's the passage mainly about? A) development of economy B) recovery of economy C) expansion of economy D) prosperity of economy
【单选题】What is the author's forecast about the future oil price or economy?
A.
The economy will stay unaffected by the high oil price.
B.
The economy will be hit if the oil price keeps high.
C.
The oil price will surely drop by the end of the year.
D.
The oil price will keep on rising in the rest of the year.
【判断题】古法印制的照片在阳光下会变色,因此要避光保存。
【简答题】由某饱和一元醛和饱和一元酮(通式为C n H 2n O, n≥3,分子中含有羰基,但不能被弱氧化剂氧化)组成的混合物共0.5 mol,其质量为23.4g,此混合物与足量银氨溶液反应,析出86.4g银。推断混合物的可能组成及质量。