问题 选择题

加热21.2g KOH和KHCO3的混合物使其充分反应后冷却,称得固体质量减少1.8g,则

下列说法中正确的是(n表示物质的量)

A.n(KOH) = 0.1mol

B.n(KOH) < n(KHCO3)

C.n(KHCO3) = 0.2mol

D.n(KOH) > n(KHCO3)

答案

答案:D

题目分析:结合方程式: ①②KHCO3+ KOH="=" K2CO3 +H2O ②2KHCO3="=" K2CO3+ CO2+H2O,如果只有反应①发生,固体减少1.8g,混合物质量为15.6g,还剩余KOH5.6g,D正确;若还有②发生,减少的质量大于1.8g。

完形填空

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What’s the most important thing for you to have in your life? Somebody mentions hardwork,      小题1: suggest knowledge, love and luck. If you arrange (排列) the 26 English letters in order and use  小题2:   to represent each of them, for example, 1 for a, 2 for b, 3 for c… 26 for z, you can change an English word   小题3:  a number. So hardwork becomes 8+1+18+4+23+15+18+11="98," meaning 98 is its mark. Knowledge:  11+ 14+ 15+ 23+ 12+ 5+ 4 + 7+ 5="96," love: 12+15+22+5="54," and     小题4:   : 12+21+3+11="47," a small mark.  小题5:   of these words can give one a full mark. What about money? It can’t, either.

Then what else? Don’t be worried. You can always find an answer      小题6:   a problem in your life, when you change your way of    小题7:    at things or doing things, or your attitude(态度). Yes, attitude is the word. See for yourself: attitude: 1+20+20+9+20+21+4+5="100," a full mark. Different attitudes lead to different courses of life. Most time people hope for a better life. It is possible that they will have a better life 小题8:  they change their attitudes. When you change your manner and become      小题9:   towards others, you’ll meet more smiling faces towards you. In the same way, if you take a positive attitude towards      小题10:   , you’ll find it’s also rewarding(有益的) though it has caused you losses(损失).

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