问题 选择题

12.下列观点解释正确的是(    )

 事实解释
A液氧和氧气的颜色不同同种分子在不同温度时,颜色不同
BKOH和Fe(OH)3与指示剂作用时颜色不同两物质中含有不同的阳离子
C酸具有相似的化学性质不同的酸溶液中含有相同的阴离子
D金刚石和石墨的性质差异较大两者的原子排列方式不同分子

答案

答案:D

单个分子不能体现物理性质,物理性质是大量分子聚集在一起体现的,所以不能说分子有颜色。故A错误

KOH易溶于水,Fe(OH)3难溶于水,难溶性碱在水溶液中不能得到氢氧根离子,所以不能使指示剂变色,所以KOH和Fe(OH)3与指示剂作用时颜色不同,不是因为两物质中含有不同的阳离子。故B错误。

酸具有相似的化学性质是因为不同的酸溶液中都含有氢离子,是都含有相同的阳离子,故C错误。

金刚石和石墨的性质差异较大,是因为两者的原子排列方式不同,故D正确。

故选D

单项选择题 案例分析题
单项选择题

Looking back on my childhood, I am convinced (1) naturalists are born and not made. Although we were all brought (2) in the same way, my brothers and sisters soon gave up their pressed flowers and insects. (3) them, I had no ear (4) music and languages, I was not an early reader and I could not do mental arithmetic.Before World War I we (5) our summer holidays in Hungary. I have only the memory of the house we lived (6) , of my room and my toys. I can hardly (7) clearly the large family of grandparents, aunts, uncles and cousins who gathered (8) door. But I do have a clear memory of the dogs, the farm (9) , the local birds and, (10) all, the insects.I am a (11) , not a scientist. I have a p (12) of the natural world, and my enthusiasm has led me into varied investigation. I love discussing my favorite topics and enjoy (13)  the midnight oil  (14)  reading about other people’s observations and discoveries. Then  (15)  happens that brings these observations together  (16)  my conscious mind. Suddenly you fancy (想象), you see the answer  (17)  the riddle, and books, of which some might honor with the title of scientific research.But curiosity, a keen eye, a good memory and enjoyment of the animal and plant world do not make a scientist; one of the outstanding and essential  (18)  required is self-discipline, a quality I lack. A scientist requires not only  (19)  but also hard training, determination and a goal. A scientist, up to a point, can be made. A naturalist is  (20) . If you can combine the two, you get the best of both worlds.

 

 

第(20)空应选择()

A.made

B.born

C.produced

D.found