问题 填空题

水是宝贵的自然资源,在工农业生产和日常生活中有广泛的应用。

(1)如图,这种净化水的方法是利用了“水”中各种物质的        不同。(填字母序号)

A.溶解性   B.熔点    C.沸点    D.密度

(2)硬水会给生产和生活带来许多不便,在生活中用

        可以区别硬水和软水。

(3)水是很好的溶剂。下表是KNO3和KCl在不同温度时的溶解度,请回答下列问题:

温度/℃010203040506070
溶解度/gKNO313.320.931.645.863.985.5110138
KCl27.631.034.037.040.042.645.548.3
 

①40 ℃时,向两个分别盛有45 g KNO3和KCl固体的烧杯中,各加入100 g的水,充分溶解后,结果如右图所示,

则乙烧杯中的溶质是         

②采用任意一种操作方法,将上述烧杯中的剩余固体全部溶解,并将溶液变为不饱和溶液。下列说法中正确的是________(填字母)。

A.溶剂质量可能不变                 B.溶液中溶质的质量分数一定减小

C.溶液质量一定增大                 D.溶液中溶质的质量分数可能增大

答案

(1)C,(2)肥皂水,(3)① KNO3 ②ACD(2分,错答漏答均不给分)

(1)蒸馏的原理是:利用各组分的沸点不同进行分离,故答案为:C

(2)用肥皂水可以区别硬水和软水,泡沫多的是软水,泡沫少的是硬水;故答案为:肥皂水

(3)将上述甲烧杯中的剩余固体全部溶解,并将溶液变为不饱和溶液,说法正确的是:升温时,溶剂质量可能不变,溶液中溶质的质量分数可能增大;溶液质量一定增大;溶液中溶质的质量分数可能减小.故答案为:硝酸钾;ACD

阅读理解

阅读理解。

     Many people believe sharks are dangerous and always try to hurt or even kill humans. In fact, 94

percent of the world's 400 species (种类) are harmless to humans. Shark Exhibition at the National

Aquarium (水族馆) in Baltimorc in the US proves this. Visitors can touch young sharks, see their eggs

develop and watch a dozen different species swim smoothly around a huge tank.

     Most people don't know that shark attacks don't happen very often. Humans are more likely to be

killed by lightning (闪电) than by a shark. And to make this point clear, the museum has set up a special

touching pool for children. There kids can learn, from an early age, not to be afraid of sharks. They can

watch them develop inside their eggs and feel the skin of the older sharks.

     "People are afraid of what they don't know," said Nancy Hotchkiss, an organizer of the exhibition.

"Sharks have been around for 400 million years and play an important role in the ocean's food chain

(食物链). We want people to discover that sharks are amazing animals that need our respect and

protection. "

     About 100 million sharks are killed every year around the world by humans. Thousands of sharks

are hunted in Asia for special food, and maxiy others are caught in nets when fishermen are hunting

other fish.

      It is a worrying situation that some countries have not put measures (措施) to protect the special

fish.

1. What can visitors do in the shark exhibition of the National Aquarium?

_________________________________________________________________

2. What is the use of that special touching pool?

_________________________________________________________________

3. Why did the organizer of the exhibition say that sharks needed to be protected?

_________________________________________________________________

4. How many sharks are killed every year around the world by humans?

__________________________________________________________________

5. What does the author worry about?

__________________________________________________________________

判断题