题干

做完“铁在氧气里燃烧”的实验后,某兴趣小组有一些疑惑不解的问题,于是进行了以下探究:

【问题一】铁燃烧时溅落下来的黑色物质中还有没有铁?

【查阅资料1】①氧化亚铁极易被氧化为氧化铁,因此自然界中铁的氧化物主要有氧化铁和四氧化三铁两种;②氧化铁为红棕色固体,不能被磁铁吸引,铁和四氧化三铁能被磁铁吸引;③铁能和稀盐酸反应生成氢气,铁的氧化物也能和稀盐酸反应,但无气体产生.

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同类题2

阅读下列短文,从下面每小题的A、B、C、D四个选项中选出最佳选项。

    Jackie visited his grandparents on their farm.And he was playing with a slingshot(弹弓)in the woods.He practised in the WOODS but he could never hit the target.As he was walking back,he saw Grandma's pet duck.Without thinking,he shot,hit the duck in the head.and killed it.He was very afraid.He knew Grandma loved the duck.She would be sad or even angry if she knew that her duck was killed.He then hid the dead duck under a tree.His sister Susan saw it all.but she said nothing.

    After lunch that day Grandma said,“Susan,let's wash the dishes.”But Susan said,“Grandma.Jackie told me he wanted to help in the kitchen today,didn't you,Jackie?”And then she whispered(小声说)to him,“Remember the duck?”So Jackie did the dishes.

    Later Grandpa asked if the children wanted to go fishing,but Grandma said,”I'm sorry but I need Susan to help clean the house.”But Susan smiled and said,“Well,that's all right because Jackie told me he wanted to help.”And she whispered again,“Remember the duck?”So Susan went fishing with Grandpa and Jackie stayed.

    These “remember the duck” went on for many days.Then finally Jackie couldn't stand it any longer.He came to Grandma and told her that he had killed the duck.She gave him a hug,and said,“Sweetheart,I know.You see,I was standing at the window and I saw the whole thing.But because I love you,I forgave you.But I just wanted to see how long you would let Susan make a slave of you.”