问题 选择题

从宏观方面看物质由元素组成,从微观方面看物质由粒子构成.下列说法不正确的是(  )

A.质子数等于电子数的某微粒,可能是一种分子或一种离子

B.只由一种分子组成的物质一定为纯净物

C.3517Cl与3717Cl互为同位素

D.46gNO2和46gN204含有的原子数相等

答案

A、质子数等于电子数的某微粒,电子转移在分子或原子内一定相同,但阴阳离子带电荷,表明向外转移了电子,故 不能是离子,故A错误;

B、纯净物是指一种物质组成的,从微观角度是只含一种分子,故B正确;

C、同位素是质子数相同,中子数不同的同元素的不同核素,3517Cl与3717Cl符合概念,互为同位素,故C正确;

D、46gNO2物质的量=

46g
446g/ mol
=1mol,含原子物质的量为3mol;46gN204物质的量=
46g
92g/mol
=0.5mol,含原子数为0.5mol×6=3mol,所以二者含有的原子数相等,故D正确;

故选A.

单项选择题
阅读理解

Honey from the African forest is not only a kind of natural sugar, it is also delicious. Most people, and many animals, like eating it. However, the only way for them to get that honey is to find a wild bees' nest and take the honey from it. Often, these nests are high up in trees, and it is difficult to find them. In parts of Africa, though, people and animals looking for honey have a strange and unexpected helper -- a little bird called a honey guide.

The honey guide does not actually like honey, but it does like the wax(蜡) in the beehives (蜂房). The little bird cannot reach this wax, which is deep inside the bees' nest. So, when it finds a suitable nest, it looks for someone to help it. The honey guide gives a loud cry that attracts the attention of both passing animals and people. Once it has their attention, it flies through the forest, waiting from time to time for the curious animal or person as it leads them tot he nest. When they finally arrive at the nest, the follower reaches in to get the delicious honey as the bird patiently waits and watches. Some of the honey, and the wax, always fall to the ground, and this is when the honey guide takes its share.

Scientists do not know why the honey guide likes eating the wax, but it is very determined (下决心) in its efforts to get it. The birds seem to be able to smell wax from a long distance away. They will quickly arrive whenever a beekeeper(养蜂者) is taking honey from his beehives, and will even enter churches when beeswax candles are being lit.

小题1: Why is it difficult to find a wild bees' nest?

A.It'ssmallinsize.

B.It'shiddenintrees.

C.It'scoveredwithwax.

D.It'shardtorecognize.小题2:What do the words "the follower" in Paragraph 2 refer to?

A.Abee.

B.Abird

C.Ahoneyseeker.

D.Abeekeeper.小题3: The honey guide is special in the way________.

A.itgetsitsfood

B.itgoestochurch

C.itsingsintheforest

D.itreachesintobees'nests小题4:What can be the best title for the text?

A.WildBees

B.WaxandHoney

C.BeekeepinginAfrica

D.Honey-Lover'sHelper