问题 填空题

用CuSO4•5H2O配制500mL0.2mol•L-1CuSO4溶液,在下列空格中填写所用仪器的名称及操作方法:

(1)经计算需要CuSO4•5H2O:______克;

(2)把CuSO4•5H2O放入烧杯中,加入适量水溶解;

(3)把所得溶液沿玻璃棒注入容积为______的______中,并用适量水洗涤______

和______2~3次,把洗涤液也移入容量瓶中,并摇匀;

(4)再缓缓地加水,到接近刻度线1cm~2cm处,改用______加水,使溶液的凹液面的最低处与刻度线相切.

答案

(1)用CuSO4•5H2O配制500mL0.2mol•L-1CuSO4溶液,需要CuSO4•5H2O质量为:0.5L×0.2mol/L×250g/mol=25g,故答案为:25;

(3)所配溶液的体积为500ml,应用500ml容量瓶配制,将固体加入到烧杯中溶解,冷却后用玻璃棒引流转移到500ml容量瓶中,并用适量水洗涤烧杯和玻璃棒2~3次,把洗涤液也移入容量瓶中,并摇匀,防止所配溶液浓度偏小,故答案为:500ml;容量瓶;玻璃棒;烧杯内壁;

(4)当加水到接近刻度线1cm~2cm处,改用胶头滴管滴加至刻度线,防止不当操作引起体积误差,故答案为:胶头滴管.

阅读理解

任务型阅读。

  The giant panda is one of the most popular animals in  the world. A giant

panda can grow up to 1. 5 meters long and weigh up to 160kg. People think the

giant panda is very lovely. ① So it is not surprising that the World Wide Fund

for Nature chose the giant panda as its symbol. The WWF tells people about

animals that they are in danger and raises money to save them.

  The giant panda only lives in the wild in China. In the early 1980s, there

were only l,000 left in the wild. The main reason why pandas are endangered is

that the area where pandas can live has become smaller.

  The WWF works to help giant pandas in the wild in  many ways. One of the

ways that helps them is to increase the size of panda reserves(自然保护区).

Some reserves need to be joined together by planting bamboo between them to

make "corridors". These are paths that lead from one reserve co another. No one

may harm the pandas in these areas. The corridors let pandas move from one

habitat(栖息地) to another to look for food.② People are working very hard to

make sure the giant panda does not die out.

1. How long and heavy can a giant panda grow to be? 

                                                       

2.将文中划线的句子①改为被动句.

So it is not surprising that _____by the World Wide Fund for Nature.

3. Why are the giant pandas endangered?

                                                       

4. Give a way to help the giant pandas in the wild, please.

                                                       

5. 将文中划线的句子②翻译成中文.

                                                       

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