问题 选择题

下列各示意图与对应的表述正确的是

A.图①表示一定条件下某化学反应的速率随时间变化的趋势图,该反应一定为放热反应

B.图②表示在四羟基合铝酸钠溶液中加入盐酸,产生沉淀的质量变化

C.图③表示等体积、等物质的量浓度的盐酸和醋酸溶液,分别加入足量镁粉,产生H2的物质的量的变化

D.图④为水的电离平衡曲线图,若从A点到C点,可采用在水中加入适量NaOH固体的方法

答案

答案:B

题目分析:A、由图①可知,一定条件下某化学反应的速率随时间变化先增大后减小,可能是发生放热温度升高造成的,也可能是生成物中有该反应的催化剂,错误;  B、在四羟基合铝酸钠溶液中加入盐酸,发生的反应依次为[Al(OH)4]- + H+  ====Al(OH)3↓ + H2O、Al(OH)3 + 3H+====Al3+ + 3H2O,产生沉淀的质量变化如图②所示,正确;C、等体积、等物质的量浓度的盐酸和醋酸溶液与足量镁粉反应,产生H2的物质的量相同,但醋酸为弱电解质,部分电离,醋酸溶液中氢离子浓度较盐酸中氢离子浓度小,反应速率慢,与图像不符,错误;D、图④为水的电离平衡曲线图,若从A点到C点,水的离子积增大,呈中性,应采用加热的方法,错误。

单项选择题

Proper arrangement of classroom space is important to encouraging interaction. Most of us have noticed how important physical setting is to efficiency and comfort in our work. College classroom space should be designed to encourage the activity of critical thinking. We may be approaching the twenty-first century, but step into almost any college classroom and you step back in time at least a hundred years. Desks are normally in straight rows, so students can clearly see the teacher but not all their classmates. The assumption behind such an arrangement is obvious. Everything of importance comes from the teacher.

With a little imagination and effort, unless desks are fixed to the floor, the teacher can correct this situation and create space that encourages interchange among students. In small or standard-size classes, chairs, desks, and tables can be arranged in a variety of ways. The primary goal should be for everyone to be able to see everyone else. Larger classes, particularly those held in lecture halls, unfortunately, allow much less flexibility.

Arrangement of the classroom should also make it easy to divide students into small groups for discussion or problem-solving exercises. Small classes with movable desks and tables present no problem. Even in large lecture halls, it is possible for students to turn around and form groups of four to six. Breaking a class into small groups provides more opportunities for students to interact with each other, think out loud, and see how other students’ thinking processes operate all essential elements in developing new modes of critical thinking. In courses that regularly use a small group format, students might be asked to stay in the same small groups throughout the course. A colleague of mine, John, allows students to move around during the first two weeks, until they find a group they are comfortable with. John then asks them to stay in the same seat, with the same group, from that time on. This not only creates a comfortable setting for interaction but helps him learn students’ names and faces.

The greatest advantage in allowing each student to find his own group might be that ().

A. the teacher saves the trouble in doing that

B. learning is made comfortable in this way

C. the teacher can easily remember students’ names and faces

D. brighter students can help slower ones

单项选择题