0  270650  270658  270664  270668  270674  270676  270680  270686  270688  270694  270700  270704  270706  270710  270716  270718  270724  270728  270730  270734  270736  270740  270742  270744  270745  270746  270748  270749  270750  270752  270754  270758  270760  270764  270766  270770  270776  270778  270784  270788  270790  270794  270800  270806  270808  270814  270818  270820  270826  270830  270836  270844  447090 

25.“ _____ to Michelle and having two beautiful girls in my house never allows me to look down upon women,” said Obama.

    A.Marrying       B.Being married    C.Having married   D.Married

试题详情

24.People tend to think that children’s IQ is _____ determines how well they are going to do in their future life.

    A.what          B.that           C.which         D.where

试题详情

23.President Hu Jintao urged every effort _____ to rescue and treat the injured when the earthquake happened in Sichuan in 2008.

    A.is made        B.must be made    C.be made        D.should make

试题详情

22.---This is my book.

---_____________ It has my name on it.

    A.Here you are!                    B.How do you find it?

    C.It’s hard to say.                 D.You must be joking!

试题详情

第一节、单项选择(共15小题,每小题1分,满分15分)

21.Chinese Vice-Premier called on Thursday for _____ all-out effort to ensure _____ food and drug safety.

    A.an; a          B.an;\           C.the; the         D.\;the

试题详情

32.9g+122.1g-100X/106            

X = 21.2g

碳酸钠的质量分数=(21.2g/32.9g)×100%=64.4% ---------1分

(2)原混合物固体中氯化钠的质量=(32.9-21.2)g =11.7g

钠元素与氯元素的质量比

=(21.2×46/1062+11.7×23/58.5)g: (11.7×35.5/58.5)g

=  (9.2+4.6)g: 7.1g

=13.8g: 7.1g

=138:71 ------------1分

答:原固体混合物中碳酸钠的质量分数为64.4%;原混合物固体中钠元素和氯元素的质量比为138: 71。

试题详情

35.(3分)

(1)解:设原固体混合物中碳酸钠的质量为X 。

   Na2CO3+CaCl2=CaCO3↓+2NaCl   

106      100     117

X      100X    117X

       106     106 

(32.9-X) g + 117X/106  

试题详情

34.(3分)

MnO2
 
 
解:设可制得氧气的质量为x

        2H2O2 ==== 2H2O + O2↑……………………….1分

         68        32

         34g       x

        ……………………………………….….1分

       ……………………………………1分

答:略

试题详情

33.(7分)

(1)漏斗 

(2) CaCO3  

(3)CaO+H2O==Ca(OH)2, Na2CO3+Ca(OH)2=CaCO3↓+2NaOH

 K2CO3+ Ca(OH)2=CaCO3↓+2KOH  (写对2个化学方程式给1分)

(4)(若假设Ⅱ成立,操作步骤、实验现象、结论对应正确给分)

实验步骤
实验现象
结论和化学方程式
取滤液分别放在三支试管中,
第一支试管中滴入足量稀盐酸
第二支试管中滴入酚酞溶液;
第三支试管中通入二氧化碳
 
无明显现象
酚酞溶液变红色
滤液出现白色浑浊
滤液中无Na2CO3,但显碱性,滤液中有氢氧化钙
CO2+Ca(OH)2=CaCO3↓+ H2O
2HCl+Ca(OH)2=CaCl2+2H2O
假设I成立(或合理)

[实验反思] NaOH、KOH

试题详情

32. (6分)

(1)澄清的石灰水变浑浊  

二氧化碳与水反应生成碳酸,碳酸使紫色石蕊溶液变红色  三

 (2)①B中氢氧化钠滴入后,气球逐渐胀大

     C试管内液面逐渐上升

②用软塑料瓶代替烧瓶

试题详情


同步练习册答案