题干

整理实验器材时,小柯将还在反应的锌和稀硫酸的残留物,倒入有少量硫酸铜溶液的废液缸中,观察到锌粒表面产生气泡的速度大大加快。对此,他十分好奇:与硫酸铜溶液混合怎么会加快锌和稀硫酸的反应速度?

查阅资料:①相互接触的两种活动性不同的金属,同时放入酸中,活动性较强的金属与酸反应产生氢气的速度会大大加快。 ②硫酸铜对锌和稀硫酸反应没有催化作用。

小柯根据下表进行实验,观察并记录现象。

组别

第一组

第二组

A

B

C

D

金属

锌片

绑有铜片的锌片

铁片

绑有铜片的铁片

30%硫酸溶液(mL)

20

?

20

20

产生气泡快慢

快

明显加快

慢

明显加快

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同类题5

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    Anny was a five-year-old girl. One day when she and her mother were in a department store(百货商店), Anny saw a plastic pearl necklace (珍珠项链). What a beautiful necklace! She wanted it very much, so she begged(乞求)her mother to buy it for her. The mother said, “Well, I can buy you the necklace, but when we get home, we should discuss what you can do to pay for it. Can we do that?” Anny agreed with much happiness, and she got the necklace.

    How much Anny loved the necklace! She wore it everywhere and every minute. Anny also did part - time jobs to make pocket money. She worked very hard. Soon she succeeded in paying off the price for the necklace.

    Anny's daddy knew how she tried her best to get the necklace. He also knew how much Anny cared about it. One night, he asked Anny if she loved him. “Sure, Daddy.” the little girl said. “Then how about giving me your necklace?” “Oh, no, Daddy! Not my necklace!” Anny cried. “Oh, dear, it's fine.” her father gave her a kiss.

    Several days later, Anny went to her daddy, with her lips(嘴唇) trembling(颤抖). “Here, Daddy. I love you.” She held out her hand. Inside it was the plastic pearl necklace that she loved so much.

    When he saw this, Anny's father smiled with surprise. He then pulled a cute box out of his pocket. Inside the box was a real and colourful pearl necklace, which was waiting for Anny for so long.