问题 选择题

下列四个图象,分别对应下列四种实验操作过程,其中正确的是(  )

A.测定不同温度下氯化钠的溶解度

B.某温度下,向接近饱和的氯化铵溶液中加入氯化铵晶体

C.向氯化铁和盐酸的混合溶液中加入过量氢氧化钠溶液

D.向两份同体积和相同质量分数的盐酸溶液中分别加入足量的铁粉和镁粉

答案

A、氯化钠的溶解度受温度的影响的变化不大,故图象与实验操作过程不对应.

B、接近饱和的氯化铵溶液加入氯化铵会溶解,溶质的质量分数会增大,但当达到饱和时就不再溶解了,溶质的质量分数也就不变了;图象应该是先上升后成一条水平直线,故图象与实验操作过程不对应.

C、向氯化铁和盐酸酸的混合溶液中加入过量氢氧化钠溶液时,先与盐酸反应,开始时不会生成沉淀,盐酸消耗完再与氯化铁反应会生成氢氧化铁沉淀,故沉淀的量先是零,在不断上升,最后形成一条水平直线;故图象与实验操作过程对应.

D、金属与酸反应时氢气来源于酸中的氢元素,因为酸的量相同,金属过量,故生成的氢气应该相等,镁的活动性比铁强,故反应速率快,反应时间短;故图象与实验操作过程不对应.

故选C.

阅读理解

阅读理解。

     In the United States,every year,Thanksgiving Day is on the fourth Thursday of November.Because

Canada is north    of  the United States,and is colder.  The harvest comes earlier in the  year,  In Canada,

people have Thanksgiving Day on the second Monday in October.

     The harvest brings a lot of food to the people.On Thanksgiving Day people in Canada and America

like to have a big meal with their friends and family just like Chinese people do at Mid-Autumn Festival.

Many Canadians and Americans put flowers.vegetables and fruits around their homes to say"Thank

you"for the harvest.

     At a Thanksgiving Day dinner,many Canadians and Americans will eat turkey,potatoes,and pumpkins

pie.These are food like the food of many years ago.They are saying"Thank you"for.the harvest that

comes every year.

1.Which country has the Thanksgiving Day like the United States?

A.Japan.    

B.China.  

C.Canada.  

D.Korea.

2.In the United States,Thanksgiving is on the fourth Thursday of     .      

A.January    

B.May    

C.November  

D.December

3.Canada has Thanksgiving earlier in the year because      

A.they like flowers    

B.the harvest come earlier

C.they have a big meal  

D.they want to be different

4.The harvest brings        to people.      

A.flowers    

B.turkeys    

C.food

D.pumpkins

5.What do people usually say on Thanksgiving Day for the harvest?

A.Good morning.

B.I'm hungry  

C.Hello.

D.Thank you.

单项选择题