问题 实验题

(6分)某同学为了验证海带中含有碘,拟进行以下实验,请回答相关问题。

(1)第1步:灼烧。操作时将足量海带灼烧成灰烬,该过程中将使用到的硅酸盐质实验仪器有       (填代号,限填3项)

A.试管  B.瓷坩埚       C.坩埚钳       D.三脚架

E.泥三角       F.酒精灯       G.烧杯  H.量筒

(2)第2步:I溶液的获取。操作是       

(3)第3步:氧化的操作中依次加入合适的试剂。下列氧化剂最好选用       (填代号)

A.浓硫酸       B.新制氯水  C.高锰酸钾溶液  D.双氧水

(4)第4步:碘单质的检验,操作是取少量第3步的溶液,滴加淀粉溶液,如果溶液显蓝色,则证明海带中含有碘。

答案

(6分)(1)BEF。(2)将灰烬转移到烧杯中,加适量的蒸馏水,用玻璃棒充分搅拌,煮沸后,过滤。(3)D

(1)灼烧需仪器:坩埚、坩埚钳、泥三角、三脚架、酒精灯、石棉

其中,坩埚、泥三角、酒精灯、石棉均含有硅酸盐

(2)海带灰中含碘溶液的获取:将灰烬转移到烧杯中,加适量的蒸馏水,用玻璃棒充分搅拌,煮沸后,过滤。这样处理的目的是充分溶解含碘物质。

(3)为了不引入新的杂质从而干扰实验,选用双氧水最好,双氧水是一种常用的绿色氧化剂,本身被还原为水,不污染环境。

填空题


A Recent Erymology of the Word "Culture"“文化”一词的新词源
Look in an old dictionary—say, a pre-1960 Webster’s—and you’ll likely find a definition of culture (1) looks something like this: "1.The cultivation of soil. 2.The raising, improvement, or development of some plant, animal (2) product. " This use of the word has its roots in the ancient Latin word cultura, "cultivation" or "tending," and (3) entrance into the English language had begun by the year 1430. By the time the Webster’s definition above was (4) , another definition had begun to take precedence over the old Latin denotation; culture was coming to mean "the training, (5) , and refinement of mind, tastes, and manners" (Oxford English Dictionary). The OED traces this definition, which today we associate (6) the phrase "high culture," back as far as 1805; by the middle of the 20th century, it was (7) becoming the word’s primary definition.
However, if you try a more modem source, like the American Heritage English Dictionary, (8) find a primary definition of culture which is substantially different than either of the two given above: "The totality (9) socially transmitted behavior patterns, arts, beliefs, institutions, and all other products of human work and thought. " Why such a (10) , and in such a (relatively) short period of time Well, in the past 40 years, the use of the (11) "culture" has been heavily influenced by the academic fields of sociology and cultural anthropology. These fields have gradually brought (12) was once a minor definition of culture (the last of eight definitions given in the old 1958 Webster’s quoted (13) ) into the mainstream.
It is easy to imagine how the US society which was so focused on "socially transmitted (14) patterns" in the sixties would come to need a word to describe the object of its interest. The civil (15) movement during this era brought everyone’s attention to bear on cultural differences within US society, while the Vietnam War (16) to emphasize the position of the US culture in relation to other world cultures.
Over time, these new uses (17) the word culture have eclipsed its older meanings, those associated with cultivation of the land and the production of (18) . You might say that an aspect of US culture over the past 40 years is its fascination with the (19) of culture itself—a fascination which has brought about many changes in the way we speak and the (20) of words which we commonly use.

单项选择题