题干

实验室利用下图装置测量久置于空气中NaOH样品的纯度。取2g样品与足量稀盐酸反应,产生气体在量程范围内,气体的密度为1.95 g/L) 请回答下列问题。

友情提示:CO2不溶于饱和碳酸氢钠溶液,也不与之反应。

上一题 下一题 0.0难度 选择题 更新时间:2014-05-14 10:10:25

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同类题3

根据短文内容,完成下列表格。(每空限填一词)   

    When you go on a trip, it's easier to get sick because your body isn't used to the food, water, and air in a new environment. Here are some tips on keeping your travel experience as healthy as possible.

    Have safe foods and drinks.

    So what foods are safe to eat? Any boiled food, fresh fruit and vegetables are safe for you. Peel(剥) the fruit before eating. You should try to drink only bottled (瓶装的) water when traveling. If you need to use tap water (自来水), you should boil it first.

Take some medicines.

You should also put some medicines in your bags, because they may be hard to find in another country. It's a good idea to always carry your medical history with you. This helps doctors well, and you won't have to worry about forgetting important information.

    Basic Safety

    You'll need to reset your thinking when it comes to traffic safety. The rules of the road aren't the same as they are at home. In some countries, people drive on the left side of the road, and you'll need to be careful before you cross the street. Be sure there are no cars coming when you step into the street: If there are, they may not stop for you!

How to Keep Healthy When You ____

★Peeled fruit, ____ food, bottled water are safe to eat and drink.

★It's hard to ____ some medicine in another country.

★Carry your medical ____ in the bag so that the doctor can know about your ____ well.

★Be sure there are no cars coming when you go across the ____.

同类题4

阅读下面文字,按要求作文。
        “责任”就是指“应尽的职责”。——《现代汉语词典》里这么说。
        “这个世界上有许多你可能不喜欢做但你不得不去做的事,这就是责任。”——英国王子查尔斯这么说。
        “尽得大的责任,就得大快乐;尽得小的责任,就得小快乐。你若是躲,倒是自投苦海,永远不能解除了。”——梁启超先生这么说。
        “孩子,要做一个负责任的人。不论发生了什么事,只要与你有关,你就要勇敢地承担那份责任,不要找借口去推卸。只有担起你应该承担的那部分责任,你就不会去怨天尤人,就会正确对待一切发生的事。承担了你的责任,你就掌握了主动权,就能够更好地解决你遇到的困难和问题。承担了你那部分责任,你就能从坎坷中吸取教训、积累经验。将来,你就能够担得起生命中更大的责任。一个勇于承担责任的人也就是一个守信誉的人、一个诚实的人、一个自尊的人和一个公正的人。”——一位普通的父亲在写给儿子的信里这么说。
       请以“责任”为题,写一篇600字以上的文章。
       提示和要求:
        ①可以大胆选择你最能驾驭的文体,写你最熟悉的内容,表达你的真情实感。
        ②不要忘了拟一个题目。
        ③文中不要出现真实的地名、校名、人名、否则会扣分。
       ④考虑到内容的充实,文章字数600字以上。
        ⑤为了方便别人阅读,请注意书写工整,卷而整洁,否则会扣分。