【单选题】The 5 paragraphs attached here are taken from the reading passage. Which paragraph contains the following information? You may not choose the same paragraph more than once. Reading for main ideas.pdf ...
【单选题】Which of the following sentences expresses a fact? A. Mary and her son must be home by now. B. Careless reading must give poor results. C. It’s getting late, and I must leave now. D. He must be workin...
【简答题】已知 K sp ( MgF 2 ) = 6.5 × 10 -9 ,将10.0 mL 0.245 mol / L Mg(NO 3 ) 2 溶液与25.0 mL 0.196 mol / L NaF溶液混合,是否有MgF 2 沉淀生成 。
【单选题】While reading the newspaper, ________.
A.
a colorful ad caught my eyes
B.
my attention was attracted by an ad
C.
I was attracted by a colorful ad
D.
what attracted me was a colorful ad
【单选题】将 2×10 -2 mol/L NaF 溶液与 2×10 -4 mol/L Fe 3+ 的强酸性溶液等体积混合后 , 溶液的 pH=1.0 。此时铁络合物的主要存在形式是 ( 已知 HF 的 p K a =3.2, Fe 3+ -F - 络合物的 lg β 1 ~lg β 3 分别为 5.3,9.3, 12.1)
【单选题】将2×10【图片】mol·L【图片】 NaF溶液与2×10【图片】mol·L【图片】 Fe【图片】溶液等体积混合, 并调pH为1.0。此时铁的主要存在形式是( )。[已知Fe-F络合物的lgβ1-lgβ3分别是5.3, 9.3, 12.1, pKa(HF)=3.2]
【多选题】将 2×10 -2 mol·L -1 NaF 溶液与 2×10 -4 mol·L -1 Fe 3+ 溶液等体积混合 , 并调 pH 为 1.0 。此时铁的主要存在形式是( )。 [ 已知 Fe-F 络合物的 lgβ 1 -lgβ 3 分别是 5.3, 9.3, 12.1, p K a (HF)=3.2]
【简答题】Read the attach ed text and choose the one that you think is the best answer to the corresponding questions. Reading 14.docx
【单选题】将2×10 -2 mol·L -1 NaF溶液与2×10 -4 mol·L -1 Fe 3+ 溶液等体积混合, 并调pH为1.0。此时铁的主要存在形式是( )。[已知Fe-F络合物的lgβ 1 -lgβ 3 分别是5.3, 9.3, 12.1, p K a (HF)=3.2]
【单选题】将2×10-2mol/L NaF溶液与2×10-4mol/L Fe3+的强酸性溶液等体积混合后,溶液的pH=1.0。此时铁络合物的主要存在形式是 (已知 HF的pKa=3.2, Fe3+-F- 络合物的lgb1~lgb3分别为5.3,9.3, 12.1)