问题 单项选择题

(66) data effectively is crucial for success in today’s competitive environment.Managers must know how to use a variety of tools. Integrated data takes information from different sources and puts it together in a meaningful and useful way. One of the difficulties of this is the (67) in hardware and software. (68) integration uses a base document that contains copies of other objects. (69) integration uses a base document that contains the current or most recent version of the source document it contains.(70) provides an overview of the program written in “plain” English,without the computer syntax.

(68)处填()。

A.Simulated

B.Duplicated

C.Dynamic

D.Static

答案

参考答案:D

单项选择题
填空题

碳化硅(SiC) 、氧化铝(Al2O3) 和氮化硅(Si3N4)是优良的高温结构陶瓷,在工业生产和科技领域有重要用途。宇宙火箭和导弹中,大量用钛代替钢铁。

(1)Al的离子结构示意图为                  

Al与NaOH溶液反应的离子方程式为                                         

(2)氮化硅抗腐蚀能力很强,但易被氢氟酸腐蚀,氮化硅与氢氟酸反应生成四氟化硅和一种铵盐,

其反应方程式为                                                

(3)工业上用化学气相沉积法制备氮化硅,其反应如下:

3SiCl4(g) + x N2(g) + 6 H2(g)   Si3N4(s) + 12 HCl(g)   △H<0  

在恒温、恒容时,分别将0.3mol SiCl4(g)、0.2mol N2(g)、0.6mol H2(g)充入2 L密闭容器内,进行上述反应,5 min达到平衡状态,所得HCl(g)为0.3mol/L、 N2为0.05 mol/L

① H2的平均反应速率是                       

② 反应前与达到平衡时容器内的压强之比=           

③ 系数 x =     

(4)已知:TiO2(s)+2Cl2(g)===TiCl4(l)+O2(g)  ΔH1=+140 kJ·mol-1

C(s)+O2(g)=== CO(g)    ΔH2 =-110 kJ·mol-1

写出TiO2和焦炭、氯气反应生成TiCl4和CO气体的热化学方程式: