试题与答案

向一定量的氢氧化钡溶液中逐滴滴加稀硫酸至过量,下列图象与该反应事实相符合的是(

题型:选择题

题目:

向一定量的氢氧化钡溶液中逐滴滴加稀硫酸至过量,下列图象与该反应事实相符合的是(  )

A.

B.

C.

D.

答案:

A、氢氧化钡与硫酸反应生成硫酸钡沉淀,当氢氧化钡消耗尽,硫酸钡的质量不再改变,故A错误;

B、向氢氧化钡溶液中加入硫酸,开始时溶液呈碱性,pH大于7,不是小于7,故B错误;

C、氢氧化钡与硫酸反应生成硫酸钡沉淀和水,硫酸钡沉淀和水不具有导电性,故导电性会逐渐减弱,当恰好完全反应,导电性为零,继续加入硫酸,导电性又回逐渐增强,故C错误;

D、有氢氧化钡时,加入的硫酸全部参加反应,不会有硫酸存在,当氢氧化钡消耗尽,再加入硫酸,硫酸的量会逐渐增多,故D正确;

故选D.

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题型:阅读理解

I heard the bees long before I saw them.

It was a very hot afternoon, and we decided to cool off in the river near my home. As we climbed down a small rocky hill toward the water, my boyfriend John suddenly started to shout then jumped into the water below. Peter and Mary quickly followed but I was too far away to jump. I was trapped.

I heard a low hum(嗡嗡声),which was growing louder. From a distance, the group of bees looked almost like a cloud of smoke. As it got closer, I realized it was actually thousands of bees flying towards me.

All I could do was cover my face with hands. Crazily, I thought that if I sat very still, the bees would think I was just another rock.

After a few minutes, I knew my plan hadn’t worked. The bees were attacking me. I could hear my friends shouting at me to get down to the pool fast.

But it wasn’t so easy. I was in great pain and the only way I could get away was to use my hands to climb down the rocks. However, I was afraid to do that at first because my face would be unprotected. The noise the bees made was so loud and frightening, but I had no choice.

I rushed down the rocks and jumped into the pool, but I don’t remember doing it. I was just so happy to be free from the pain. I was safe, and the water felt wonderful.

But we still weren’t out of danger. Every time we tried to climb out of the pool, the bees flew back over our heads. We spent the next three hours in the water, putting our heads under the water from time to time to avoid the bees until they finally lost interest.

小题1: How many people went swimming that day?

A.Two.

B.Three

C.Four

D.Five小题2:The underlined word “it” (in Paragraph 3) refers to        .

A.a rock

B.the group of bees

C.a hill

D.the river小题3: At first why didn’t the writer want to climb down the rocks?

A.She was afraid she would fall.

B.She was too far away from pool.

C.She thought the bees would follow her.

D.She didn’t want her face to be unprotected.小题4: How did the writer escape the bees?

A.She covered her face with her hands.

B.She hid behind the rocks.

C.She jumped into a water pool.

D.She pretended to be a rock.小题5:In what order are the following mentioned in the story?

a. The writer rushed down the rocks.

b. John jumped into the water.

c. The low hum grew louder.

d. The bees flew back over their heads.

e. The bees were attacking the writer.

A.b c e a d

B.b a e c d

C.c d e a b

D.c b d e a

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