问题 问答题

酒楼的食品在制作时常加入味精,味精的主要成分是一种有机化合物--谷氨酸钠,其化学式为C5H8NO4Na.根据题中的信息计算:

(1)每个谷氨酸钠分子中含______个原子.

(2)谷氨酸钠中碳、氢元素的质量比为______;

(3)169g谷氨酸钠中含钠元素的质量为______ g.

答案

(1)每个谷氨酸钠分子中含有的原子总数=5+8+1+4+1=19;

(2)谷氨酸钠中碳、氢元素的质量比=(12×5):(1×8)=15:2;   

(3)169g谷氨酸钠中含钠元素的质量=169g×

23
169
×100%=23g.

故答案为:(1)19;(2)15:2;(3)23.

完形填空

阅读下面短文,掌握其大意,然后从1-15各题所给的四个选项(A、B、C和D)中,选出最佳选项,并在答题卡上将该项涂黑。

In a small village, there lived a potter(陶工) who had a donkey. Every day his donkey would carry soil from the ___1___ to his house. Since the field was quite far off, the potter would ___2___ under a tree midway, tying(拴) his donkey nearby.

One day, the potter __3__ to take the rope with which he tied the donkey every day. When he reached the __4__, he became worried and didn’t know what to do. At that time, a saint(圣人) __5__ to be passing by. When the potter told the saint what his __6__ was, he said, “Take the __7__ to the place where you tie him every day. __8__ to tie him using an imaginary rope. He won’t run away.” The potter did what the saint had said.

When he woke up, to his __9__ and relief, he found the donkey standing in the __10__ place. But to his frustration, when he prepared to leave for __11__, the donkey did not move. __12__, the potter saw the wise saint again and told him about the donkey’s __13__ behavior. The saint said, “Go and pretend to untie the rope.” The potter __14__ the saint’s advice.

Now the donkey was ready to leave for home. The potter thanked the wise saint and went home __15__ his donkey.

1. A. factory      B. garden           C. field             D. village

2. A. stand        B. rest             C. sing             D. dance

3. A. forgot       B. decided          C. expected         D. agreed

4. A. stone        B. tree             C. bridge           D. house

5. A. failed        B. attempted        C. happened        D. managed

6. A. animal       B. plant            C. problem         D. result

7. A. bird         B. flower           C. donkey          D. rope

8. A. Believe      B. Learn           C. Wish           D. Pretend

9. A. surprise      B. disappointment    C. anger           D. regret

10. A. similar      B. special           C. same           D. wrong

11. A. field        B. school           C. home           D. hospital

12. A. Quickly     B. Luckily           C. Unfortunately    D. Badly

13. A. funny       B. foolish           C. proper          D. strange

14. A offered       B. followed         C. refused         D. received

15. A. happily      B. sadly            C. seriously       D. casually

问答题 简答题