钠元素对人类生命和生活具有重要意义. (1)如图所示,钠元素的相对原子质量为.

题型:填空题

问题:

钠元素对人类生命和生活具有重要意义.

(1)如图所示,钠元素的相对原子质量为             

(2)钠元素广泛存在自然界中,亚硝酸钠(NaNO2)是一种常用的防腐剂,其中氮元素的化合价为  ;小苏打是发酵粉的主要成分,其化学式为    ;氯化钠在生活中常用于         

(3)将金属钠与液态氨反应得NaNH2,再将NaNH2与N2O反应可生成NaN3,反应的化学方程式为2NaNH2+N2O=NaN3+NaOH+X,则X的化学式              

(4)叠氮化钠(NaN3)被广泛应用于汽车安全气囊,汽车经撞击后,30毫秒内引发NaN3迅速分解生成两种单质,写出反应的化学方程式                            

考点:化学反应方程式的书写化学图标化学反应方程式的配平化学反应方程式的意义
题型:填空题

“生产成本”账户期末借方余额表示()。

A.生产成本

B.生产费用

C.产成品成本

D.在产品成本

题型:填空题

如图是呼吸系统的模式图,请据图回答下列问题。   

(1)填写图中结构的名称:A____;B____;C____;D____;F____。     

(2)G和C的末端形成许多肺泡,H和D就是由这些_______构成的,是___的主要器官。     

(3)肺泡的结构特点使得氧和二氧化碳很容易在肺泡和_______之间进行气体交换。     

(4)H和D内的气体经呼吸道排出体外时,胸廓的大小变化是____。     

(5)鼻涕是由_____形成的,痰液是由_____形成的。

题型:填空题

个人年度总额内的结售汇,可以委托其直系亲属代为办理。受托人应分别提供()

A.提供委托人和受托人的有效身份证件

B.委托人的授权书

C.直系亲属关系证明。

D.亲属证明

E.委托人的证明书

题型:填空题

啸叫产生的原因是什么?

题型:填空题

As the pace of life continues to increase, we are fast losing the art of relaxation. (1) you are in the habit of rushing through life, being on the go from morning till night, it is hard to (2) down. But relaxation is (3) for a healthy mind and body.Stress is a (4) part of everyday life and there is no way to (5) it. In fact,it is not the bad thing that it is often supposed to be. A (6) amount of stress is important to provide motivation and give (7) to life. It is only when the stress gets out of control (8) it can lead to poor performance and (9) health.The amount of stress a person can bear(10) very much on the individual. Some people are not afraid of stress, and such (11) are obviously chief material for managerial responsibilities. Others lose heart at first (12) of unusual difficulties. When exposed to stress, in (13) form, we react both chemically and physically. In fact we (14) a choice between escape and fight. But in more ancient days they made the (15) between life and death. The crises (危机)we meet today are (16) to be so extreme,but however little the stress,it requires the same response. It is when such a reaction (17) long,through continued exposure to stress,that health becomes (18) .Such serious conditions as high blood pressure and heart diseases have (19) links with stress. (20) we canno! remove stress from our lives we need to find ways to deal with it.It would be unwise to do so even it we could.So what do you think of stressWhat is your way to deal with it.

第(8)空应选择()

A.when

B.why

C.that

D.how

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