【简答题】下列各组反应哪几组是可逆反应?为什么? (1)2H 2 +O 2 2H 2 O与2H 2 O 2H 2 ↑+O 2 ↑ (2)NH 3 +H 2 O====NH 3 ·H 2 O与NH 3 ·H 2 O==== +OH - (3)CaCO 3 (s)====CaCO 3 (aq)与CaCO 3 (aq)====CaCO 3 (s) (4) +OH - ====NH 3 ·H 2 O与NH 3 ·H...
【单选题】'This park has more than 200 waterfalls that are 5 feet or higher. And 50 of them have never been mapped or photographed,' says park historian Lee Whittlesey. 'Now that's a ______ to the size of Yello...
【单选题】He is a good composer,________ he has taught me a lot.
【单选题】该视频中翻译或者表述可能有误的一句话是
A.
你们把自己的劳动,像商品一样出售给你们的雇主
【单选题】从某些性质看,NH 3 与H 2 O相当,NH 4 + 与H 3 O + 、NH 2 - 与OH - 、NH 2 - 与O 2 - 都有相当关系,下列有关方程式不正确的是( )
A.
NH 4 Cl+KNH 2 =KCl+2NH 3 ↑
B.
M+2NH 3 =M(NH 2 ) 2 +H 2 ↑(M为二价活泼金属)
C.
2HCl+ M(NH 2 ) 2 =MCl 2 +2NH 3 ↑
D.
2NH 4 Cl+MO=M(NH 2 ) 2 +2HCl+H 2 O
【简答题】The composer has been looking for ways to combines ______(harmony)and rhythmic structure.
【简答题】NH 4 NO 2 受热分解产物为 (A) NH 3 +HNO 2 ; (B) N 2 +H 2 O; (C) NO+H 2 O; (D) N 2 O+H 2 O。
【简答题】将下列各对分子间氢键按由强到弱的顺序排列。 (1)HF与HF (2)NH 3 与NH 3 (3)H 2 O与H 2 O (4)H 2 O与NH 3
【单选题】固体重铬酸铵(NH 4 ) 2 Cr 2 O 7 )受热分解产物为( )。