题目内容

“It would have been bad manners to make his guests feel foolish or uncomfortable．”“bad manners”means __________．

A. ugly
B. dishonest
C. impolite
D. shameful

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A. passed
B. past
C. old days
D. out-of-date

A.ConsequentlyB.MoreoverC.UnexpectedlyD.However

A. Consequently
B. Moreover
C. Unexpectedly
D. However

某药物的水解反应为一级反应。将浓度为3.17×10^-4mol·L^-1的该药物在37℃，pH=5.50时水解1367min后，测得其浓度为3.09×10^-4mol·L^-1。若药物含量降低至原含量的90%即为失效，问此药物的有效期应为多长？

乙酸乙酯的水解：CH₃COOC₂H₅+NaOH→CH₃COONa+C₂H₅OH为二级反应。在25℃时，将0.0400mol·L^-1乙酸乙酯溶液与0.0400mol·L^-1NaOH溶液等体积混合，经25.0min后，取出100.0mL样品，测得中和该样品需0.1000mol·L^-1HCl溶液15.20mL。试求：