【单选题】已知 : (1) CaC 2 O 4 = Ca 2+ + C 2 O 4 2- K ɵ =2.3×10 -9 (2) HAc = H + + Ac - K ɵ =1.8×10 -5 (3) HC 2 O 4 - = H + + C 2 O 4 2- K ɵ =6.4×10 -5 则可计算反应 CaC 2 O 4 + HAc = Ca 2+ + HC 2 O 4 - +...
【单选题】Speak a: Merry Christmas! Speak b:________________
【单选题】常温下已知电离常数: K b (NH 3 ·H 2 O) = 1.8 × 10 - 5 ; K a1 (H 2 C 2 O 4 ) = 5.9 × 10 - 2 , K a2 (H 2 C 2 O 4 ) = 6.4 × 10 - 5 。下列说法正确的是 ( )
A.
. (NH 4 ) 2 C 2 O 4 溶液中 , c (NH ) = 2 c (C 2 O )
B.
.等物质的量浓度的氨水和 H 2 C 2 O 4 溶液等体积混合,所得溶液呈碱性
C.
. pH = 11 的氨水和 pH = 3 的 H 2 C 2 O 4 溶液等体积混合,所得溶液呈酸性
D.
.用 H 2 C 2 O 4 溶液中和氨水至中性时,溶液中 c (NH ) = 2 c (C 2 O ) + c (HC 2 O )
【单选题】Speaker A: Merry Christmas! Speaker B:________________
【简答题】听小对话,选答案。 1. What is Uncle Wang? A. He is a teacher. B. He is a doctor. C. He is an assistant 2. What’s the girl’s favorite? A. Man and Nature. B. News Report. C. Animal World 3. What does Brad want t...
【单选题】如图所示 ,R1 和 C1 形成的反馈类型是 __________
【简答题】iphone8充电爆裂怎么回事? iphone8电池为什么会爆炸?
【简答题】已知 H 2 C 2 O 4 的 K a1 ө (H 2 C 2 O 4 )=6.5 × 10 -2 , K a2 ө (H 2 C 2 O 4 )=6.1 × 10 -5 ,则 HC 2 O 4 - K b ө