题干

请结合图示实验装置,回答下列问题。

①写出标号g的仪器名称:____

②用氯酸钾和二氧化锰制氧气选用的发生装置是____(选填序号),反应的化学方程式为____;用向上排空气法收集氧气,检验氧气是否收集满的方法是____

③用B装置加入双氧水和二氧化锰制氧气,使用分液漏斗的优点是____;若用D装置收集氧气,当____时,才能将导管伸入集气瓶中进行收集;

④取一定质量分数的过氧化氢溶液34g于烧杯中,加入一定量的二氧化锰,完全反应后,称得烧杯内剩余物质的总质量是33.8g,将杯内剩余物质过滤、洗涤、干燥后得滤渣3g。请根据要求回答下列问题:

a.生成氧气的质量是____g;

b.所取溶液中过氧化氢的物质的量是____?(请根据化学方程式计算)

⑤F装置可用来测量生成的O2 的体积,检验该装置气密性的方法是:当把针筒里的活塞向左推时,若看到____,说明气密性良好;

⑥实验室可用B或C装置制备二氧化碳,反应的化学方程式为____,C相对于B装置的优点是____。若用E装置收集二氧化碳,气体应从____端通入(选填“a”或“b”);

⑦实验室也可以用A 装置制备二氧化碳,推测其反应物是____

A.NaHCO3 固体     B.大理石与稀盐酸      C.木炭与氧气

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答案(点此获取答案解析)

\u9525\u5f62\u74f6,A,2KClO3 =\u25b3MnO2 2KCl+

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    People can't see you when you're speaking on the phone,but they can hear you.So,the way you speak is especially important.In fact,researchers have calculated that 80% of communication over the phone is through your tone of voice; and only 20% is from the words you use.Here are our top tips on how to speak over the phone.

⒈Facial Expressions

    Your facial expression can influence your voice.For example,if you smile,your voice will sound warm and friendly,just the opposite,if you have an angry look on your face,it can make you sound unpleasant.

⒉Volume

    If you speak too loudly,you could sound angry.And if you speak too softly,it'll be difficult to hear you.So,speak loudly enough to be heard clearly,but not so loud that you're shouting.

⒊Pace

    The pace of your voice is how quickly you speak.And this can show how you feel.For example,an angry person might speak faster than normal.Or a downhearted person might speak very slowly.Try speaking a little more slowly than normal.This will make you sound confident,and it'll make it easier for the other person to understand you.

⒋Gestures

    Gesturing can influence the tone of your voice.When you gesture,you bring more air into the lungs,which can make your voice sound warmer.Gestures are also useful to help you stress the right words or even find the words you need.The best thing about gesturing during a phone call is that no one can see what you're doing,so you can gesture as wildly as you like!

⒌Movement

    If you're feeling nervous,stand up and move around.It will reduce the nervousness in your body and help your voice to sound more confident.

⒍Pauses (停顿)

    Using pauses every now and then can help you to slow down.This will make you sound more confident and in control.Also,if you pause after giving some new information,it'll give the other person time to understand it.At the same time,listen to how the other person uses pauses.They could tell you something about the speaker's feeling.For example,when a speaker is really angry,he might use pauses and says,"I…am…so…angry…"