题干

Shop F.Y. – Elisabeth Online Shopping!
    Do you want to buy some good things? Do you want to buy them at low prices? Do you want to buy them at home? Do you want to buy them right now?
F. Y. can help you!
    There are hundreds of good things for you to choose. Just do it! The thing you need is a computer. Here is the way to buy things online.
    Choose a kind of thing you want to buy and click on the describing words. For example, if you want to buy a sweater, you can click on the word – clothes.
    Choose the color and size. If you want a small black sweater, you can click on the words- small and black. You can see a list of small black sweaters with the price. You just click on the sweater you like. Enter your name, address, telephone number and ID card number.
    OK! The shop assistant will send your sweater in one day. Isn't it easy? Enjoy your shopping here!
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同类题3

某兴趣小组话动中,同学们按图1装置对“可燃物燃烧的条件”进行探究.探究过程中,大家对磷燃烧生成的大量白烟是否危害人体健康提出疑问.

【查阅资料】白磷的着火点是40℃,红磷的着火点是240℃,…燃烧产物五氧化二磷是白色固体,会刺激人体呼吸道,可能与空气中水蒸气反应,生成有毒的偏磷酸(HPO3).

【变流与讨论】白烟对人体健康有害,该实验装置必须改进.

【改进与实验】同学们按改进后的图2装置进行实验.

请你帮助他们将表补充完整.

现象

解释

a试管中白磷燃烧,热水中白磷没有燃烧.b试管中红磷没有燃烧.

b试管中红磷、热水中白磷都没有燃烧的原因是

____;②____

【反思与评价】

(1)改进后的图2装置与图1装置比较,优点是____

(2)小林同学指出图2装置仍有不足之处,并设计了图3装置,其中气球的变化是____ ,作用是____

【拓展与迁移】实验小结时,小朱同学说:“待a试管冷却后,如果将试管口紧贴水面(室温下).并取下橡皮塞,将看到液体进入试管.”这一说法得到大家的一致认同.小晶问:“如果不考虑橡皮塞占试管的容积,进入a试管内液体的体积会是多少呢?大家争论后,出现两种预测.甲:接近试管容积的15;乙:不一定接近试管容积的15.你赞同的预测是____ (填“甲”或“乙”),理由是____ .