氢气可被用作清洁能源，但它的制取、存储和运输都很困难。科学家_爱下问搜题

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问题填空题

氢气可被用作清洁能源，但它的制取、存储和运输都很困难。科学家开发出一种用糖类制取氢气的新技术，有望解决这几大问题。以这项技术为基础，未来的氢动力汽车将携带易于存储的糖类，如淀粉，其化学式是(C₆H₁₀O₅)n。科学家使用由多种特殊的酶组成的混合物，将淀粉和水转变成CO₂和H₂的混合气体，将CO₂除去后，H₂进入燃料电池产生电力，驱动汽车前进。燃料箱容量为55升的汽车可携带约27千克淀粉和21千克的水，完全转变，可以产生4千克氢气，其余为CO₂。根据以上材料，请回答下列问题：

(1)利用该项技术，汽车运动时时的机械能最终由下列哪种能量转化而来

A．化学能 B．太阳能 C．电能 D．热能

(2)混合物中的酶具有高效性、多样性和性。

(3)请根据质量守恒定律配平淀粉和水反应的化学方程式

(C₆H₁₀O₅)n+ H₂O H₂+ CO₂

(4)若一辆氢动力汽车正常行驶时，功率是70千瓦，氢气的热值是1.4×10⁸焦／千克，燃料电池的能量转化效率是50%，在阻力不变和不考虑其它能量损耗时，要使该车能正常行驶，汽车每小时至少消耗氢气千克

答案

(1) B

(2) 专一

(3) 1，7n，12n，6n

(4) 3.6

完形填空

Trees are useful to man in three very important ways.

The first important way is that they provide man with food, wood and other products. Trees provide man and animals with food to live on the earth. It’s not easy for man to live on the earth without trees.

The second important way is that trees give us shade. On a hot summer day, people are eager to (急于) have a rest under the shade of a tree after they have walked a long way. You can imagine how important the shade of a tree is to man and animals.

The third important way is that trees help to prevent droughts and floods. However, in many parts of the world, man has not realized the third important way. He has cut trees down in large numbers. In the end, he finds that he has lost the best friends he had.

根据短文内容填空，每空一词。

小题1:Trees give food to _____ man _____ animals.

小题2:Trees are _____ and _____ to man.

小题3:On a _____ summer day, if we sit under the _____ of a tree, we can feel quite cool.

小题4:In many parts of the world, man has not realized that trees help to prevent _____ and _____.

小题5:If we don’t want to lose our best friends—trees, we must stop others from _____ _____ too many of them.

计算题

某校化学课外活动小组的同学需要一些硫酸做化学实验，现有一瓶未开启的浓硫酸，标签如图。请阅读标签上的说明，并通过计算回答下列问题：

（1）若需要配制368 g 19.6% 的稀硫酸，应取该浓硫酸多少毫升？

（2）课外活动小组的同学实验结束后需要处理实验中产生的废碱液（溶质是NaOH，其它物质不跟硫酸反应），已知该废碱液中NaOH的质量分数为4.0%，若要中和该碱溶液1000 g，通过计算确定需要98.0%的浓硫酸多少克？

（3）中和后所得溶液中溶质的质量分数为多少？