【单选题】若向一定浓度的 NaH 2 PO 4 溶液中加入 NaOH 固体配制 pH 为 7.21 且与血液等渗的缓冲溶液(假设溶液体积不变 ), 则原 NaH 2 PO 4 溶液的浓度应为 ( 已知常温下 H 3 PO 4 的 p K a1 =2.16,p K a2 =7.21,p K a3 =12.32)
【简答题】Read the following passage. Complete the diagram by using the information for the passage. Write NO MORE THAN 3 WORDS for each answer. Since it was founded a year ago, the babysitting pool has become ...
【简答题】Write an essay of no less than 160 words in response to the prompt below.Write the passage on the answer sheet. “Books are the quietest and most constant of friends;they are the most accessible and wi...