题干

对知识的归纳与整理是学习化学的重要方法,现有三个反应的文字表达式:

①硫+氧气 →点燃 二氧化硫

②碳+氧气 →点燃 二氧化碳

③铁+氧气 →点燃 四氧化三铁

通过比较,发现它们有许多共同点,请你写出其中三点:

①____;

②____;

③____.

上一题 下一题 0.0难度 选择题 更新时间:2018-07-03 05:08:33

答案(点此获取答案解析)

反应物中都有氧气,都是化合反应,反应条件都是“点燃”

同类题1

根据课文内容填空

①雨停了。____出来了。____挂在天空。____叫了。____又坐在网上。池塘里水满了,____也叫起来了。

②____清谷天,夏满芒夏暑相连,秋处露秋寒霜降,____小大寒。“清”指____,“小”指____。

同类题2

阅读理解

    Beijing's markets will soon be flooded with more and cheaper colorful fruit such as orange, mangos and green durian(榴莲)all year round.

    Thanks to a new free trade agreement signed last Monday between China and the Association of Southeast Asian Nations(ASEAN),more and more tropical Southeast Asian fruit will enter the country.

    The agreement means that from July 1,2005, China and ASEAN countries will begin to cut tariffs. There are about 7,000 products included in the cuts. As global communication develops, countries are trading more and more goods with each other. When products are sold across national borders, countries put a tax on them. This type of tax is called a tariff. Just like removing an obstacle from the path of these goods, the reduction of tariffs will encourage trade between China and ASEAN countries. It means more products and lower prices.

    The agreement will bring real benefits for Chinese customers, said a Chinese Foreign Ministry spokesman. “In the Beijing markets you will easily find more tropical fruit like durian, which used to very, very, very expensive. Now they will be cheaper.” The current tariff rate on durian is 22 per cent but will fall to zero in 2005.

    In the first 10 months of this year China did US$84.6 billion of trade with ASEAN countries. Experts believe this may reach US$100 billion next year. Founded in 1967, ASEAN now includes Indonesia, Malaysia, Singapore, the Philippines, Thailand, Brunei, Viet Nam, Myanmar, Cambodia and Laos.

根据短文内容,选择最佳答案,并将选定答案的字母标号填在题前括号内。

同类题3

1856年,英法发动侵华战争的目的是(  )

同类题4

用“侯氏制碱法”制得的纯碱常含有少量的氯化钠.将10g含有氯化钠的纯碱溶解于102.32g稀盐酸中,恰好完全反应,收集到3.52g的气体(假设生成的气体全部逸出).

求:反应后得到的不饱和溶液中溶质的质量分数.

同类题5

下列词语书写完全正确的一项是(    )
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