题干

除去下表内各物质中含有的少量杂质,写出除杂试剂,并填写分离方法.

序号

物质

杂质

所加试剂

分离方法

(1)

NO

NO2



(2)

Fe粉

Al粉



(3)

氯化钠固体

氯化铵固体

/


上一题 下一题 0.0难度 选择题 更新时间:2017-10-31 10:24:39

答案(点此获取答案解析)

解:(1)NO2能和水反应生成NO,故可以用水洗气以除去NO中的NO2

(2)Al既能和酸反应又能和碱反应,而Fe只能和酸反应,故可以用氢氧化钠溶液除去铁中的铝;

(3)氯化钠受热不分解,而氯化铵受热易分解,故可以用加热的方法来除去氯化钠中的氯化铵.

故答案为:

同类题1

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阅读理解

Fixed or growth mindset — which do you have?

    We live in an uncertain world with all the technological advances we are experiencing, which meanse is a requirement for a change in midset (思维模式). In order to be on top of our game both personally and organizationally, we need to develop a growth mindset.

    A fixed mindset supposes that you have native abilities and are naturally clever or skilled in certain areas of life. When you receive infonnation about how you have performed in a test or set of tasks t you may worry about how you are judged. Our parents probably said to us when we were young,"Since you scored really well in the test, you must  be clever." However, by being repeatedly told “You are clever” or “You are really good at your job”,a person's self—respect is actually dainagcd.

    The  growth—mindset  person a view life as a series of exciting challenges and  want  to constantly  learn. Brain activity occurs in this mindset when they receive information about what they could do belter or improve. They do not view their abilities as fixed or us failure. Learning is king and the more they practice , the more they know they will succeed.

    What is important is giving praise around process and not around ability. For example , instead of saying"Since you got a great score, you must be clever" f say " You got a great score, and you must have tried really hard". This creates challenge in individuals and the meaning of mindsets is massive for business. Fixed-mindset managers are not fans of giving feedback (反馈). They do not want to stretch themselves or others because they fear failure. Therefore their business may stand still because there is no risk or innovation (创新) occurring.

    Listen from your own fixed mindset — for example ," I can't  do that” — and answer with a growth-mindset response — “I can't do that yet!" Remember  there is no such thing as failure and there is s only learning. If you don't fail occasionally ,you will never learn to change and grow.