问题 实验题

蛇纹石矿可以看作由MgO、Fe2O3、Al2O3、SiO2组成。由蛇纹石制取碱式碳酸镁的实验步骤如图

(1)蛇纹石矿加盐酸溶解后,溶液里除了Mg2+外,还含有的金属离子是____。

(2)进行I操作时,控制溶液pH=7~8(有关氢氧化物沉淀的pH见上表)Ca(OH)2不能过量,若Ca(OH)2过量可能会导致____溶解、____沉淀。

(3)从沉淀混合物A中提取红色氧化物作颜料,先向沉淀物A中加入____(填人物质的化学式),然后 ____(依次填写实验操作名称)。

(4)物质循环使用,能节约资源。上述实验中,可以循环使用的物质是____(填写物质化学式)。

(5)现设计一个实验,确定产品aMgCO3·bMg(OH)2·cH2O中a、b、c的值,请完善下列实验步骤(可用试剂:浓硫酸、碱石灰):

①样品称量

②高温分解

③____

④____

⑤MgO称量

(6)18. 2g产品完全分解后,产生6.6gCO2和8.0gMgO,由此可知,产品的化学式中:

a=____;b=____;c=___

答案

(1)Fe3+、Al3+

(2)Al(OH)3 ;Mg(OH)2

(3)NaOH; 过滤、洗涤、灼烧

(4)CO2

(5)③测出CO2的质量; ④测出水蒸气的质量

(6)3; 1 ;3

改错题

短文改错

    假定英语课上老师要求同桌之间修改作文,请你修改你同桌写的以下作文,文中共有10处语言错误,每句最多有两处.错误涉及一个单词的增加,删除和修改

增加:把缺词处加一个漏字符号(∧),并在其下面写出该词

删除:把多余的词用斜线(\)划掉

修改:在错的词下划一横线,并在该词下面写出修改后的词

注意:

1.每处错误极其修改均限一词

2.只允许修改10处,多者从第11处不记分

Dear Jin Jing,

     Your problem is common one among middle school students. Maybe the following advices can

help you. First in all, believe in yourself. Your greatest problem is that you lack self-confidence. The

first thing you must do it is to smile at your classmates. One smile speaks loud about your wish to

make friends than any words. Your smile will show that you are friendly to him. Next, trying talking

with a student who is as shy as you or who share the same interest with you. You can discuss your

studies with a classmate and you can also talk about your hobbies. Unless anyone is in trouble, you

should be ready to help him or her. Once you have confidence, you can make as many friends as

possibly.

                                                                                Yours,

                                                                                  Lily

_____________________________________________________________________________

单项选择题