问题 选择题

木糖醇是目前市场上一种理想的蔗糖替代品,在某些温度下其溶解度分别为:30℃时70g、50℃时84g,、60℃时90g。右图表示的是木糖醇等固体的溶解度曲线。根据曲线判断下列说法错误的是

A.X为木糖醇的溶解度曲线

B.随着温度的升高,Z物质的溶解度逐渐减小

C.30℃时,X、Y、Z三种物质的饱和溶液中溶质质量分数最大的是Y

D.50℃时,Y、Z两物质的溶解度相等

答案

答案:C

解:A、利用三组数据“30℃时70g、50℃时84g、60℃时90g”中的第一或第三组数据,找到温度与溶解度的交点所在的曲线即为木糖醇的溶解度曲线.第二组数据正好落在两条曲线的交点上,无法确定曲线.曲线X为木糖醇的溶解度曲线,说法正确;

B、曲线Z随温度升高而下降,表明Z物质的溶解度随温度升高而减小,因此说法正确;

C、某温度下饱和溶液的溶质质量分数= ×100%(S为该物质在该温度下的溶解度),在30℃时,X、Y、Z三种物质的溶解度大小关系为:SZ>SX>SY,物质Y的溶解度SY最小,所以此时物质Y的饱和溶液的溶质质量分数也最小,而非是最大.说法错误;

D、50℃时,Y、Z两物质的溶解度曲线交于一点,表明此时两物质的溶解度相等.说法正确.

故选C

多项选择题
阅读理解

A good friend of mine was complaining about her son the other day.“Did you notice,” she started, “how he didn’t wait for me to get my salad before he dove into his?”

True enough, the boy attacked his plate faster than a cat in the wild.Without manners, we’re no more than animals.Actually, that’s not true.I’ve been watching and feeding a group of wild cats, and they show unusual politeness toward each other.Even when food is scarce, they take turns, leaving at least a small part for the next in line.

My mother educated her three children to have good manners all the time.We were made to feel very uncomfortable as if we were sitting on pins and needles until we got used to saying please, thank you, pardon me, and I’m sorry.And I have to say, while it was a painful learning experience, it was one of the most valuable.

I can’t tell you how often I sat with my friends, eating at their dinner tables, and their parents thought highly of my good manners.While it was a little embarrassing, I knew even then that my mother’s teachings were paying off.

Many years later, when I was attending seminars across the country, my manners were quite useful.

While I regret that I haven’t been a perfect example, I’m still working on it.I suppose, in this regard, my mother lives on through me.I didn’t have her beautiful singing voice or her green eyes, but she did make sure I received one of her finest characteristics.

小题1:What did the writer’s friend most probably complain about?

A.Her son’s eating too quickly.

B.Her son’s not having a healthy diet.

C.Her son’s not having good table manners.

D.Teenagers’ not having good manners.小题2:The underlined word “scarce” in Paragraph 3 probably means “________”.

A.too much

B.not delicious

C.not enough

D.quite hot小题3:We learn that the writer’s mother __________.

A.was strict about her children’s manners

B.never punished her children

C.had beautiful blue eyes

D.was not good at singing小题4:What does the writer think of her experience of learning good manners?

A.Easy and relaxing

B.Painful and valuable

C.Easy but useless

D.Too horrible小题5:We can infer from the passage that the writer _________.

A.is surely liked by everyone around her

B.is not satisfied with most people’s manners around her

C.thinks she has been a perfect example to the young

D.thanks her mother for teaching her the good manners a lot