题目内容

10.I ping-pong quite well, but I haven’t had time to play since the New Year.

A. will play
B. have played
C. played
D. play

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11.When he was alive, the old scientist used to say that knowledge from practice and he gained his experience by doing a lot of practical work.

A. was coming
B. will come
C. comes
D. would come

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12.— Sorry, I forget to post the letter for you.— Never mind, it myself tonight.

A. I’m going to post
B. I’ve decided to post
C. I’ll post
D. I’d rather post

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下列三种缓冲溶液,缓冲能力(或缓冲容量)最大的是( )

A. 1.0 mol·L-1HOAc + 1.0 mol·L-1NaOAc;
B. 0.01 mol·L-1HOAc + 0.01 mol·L-1NaOAc;
C. 1.0 mol·L-1HOAc + 0.01 mol·L-1NaOAc;
D. 0.01 mol·L-1HOAc + 1.0 mol·L-1NaOAc。

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欲配制pH为3左右的缓冲溶液,应选下列何种酸及其共轭碱(括号内为pKa):

A. HOAc(4.74)
B. 苯甲酸(4.21)
C. 一氯乙酸(2.86)
D. 二氯乙酸(1.30)

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10.I ping-pong quite well, but I haven’t had time to play since the New Year.

A. will play B. have played C. played D. play

11.When he was alive, the old scientist used to say that knowledge from practice and he gained his experience by doing a lot of practical work.

12.— Sorry, I forget to post the letter for you.— Never mind, it myself tonight.

下列三种缓冲溶液,缓冲能力(或缓冲容量)最大的是( )

欲配制pH为3左右的缓冲溶液,应选下列何种酸及其共轭碱(括号内为pKa):

A. will play
B. have played
C. played
D. play