下列说法正确的是
A．0.18mol·L-1的醋酸加水稀释，c(H+)/c(OH-)减小
B．体积相同、pH相同的醋酸和盐酸完全溶解等量的镁粉，后者用时少
C．向水中加入少量固体硫酸氢钠，c(H+)增大，Kw变大(不考虑温度变化)
D．V1LpH=11的NaOH溶液与V2LpH=3的HA溶液混合，若混合液显中性，则V1≤V2
答案：A
醋酸加水稀释促进电离使n(H+)的物质的量增加，但c(H+)减小，c(OH-)增大c(H+)/c(OH-)减小A正确；体积相同、pH相同的醋酸和盐酸与镁粉反应时，开始反应速率相同，然后醋酸快（促进醋酸的电离使c(H＋)比盐酸中的大），则后者用时多，B错误；Kw与温度有关，温度不变，Kw不变，C错误；若HA为强酸，有V1=V2，若HA为弱酸，等体积混合呈酸性，现呈中性则V1大于V2，D错误。
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| The school was across the street from our home and I would often watch the kids as they played during the break.She seemed so small as she pushed her way __1__ the crowd of boys on the playground.She __2__ from them all. I began to notice her at other times, basketball in hand, playing __3__.She would practice dribbling (运球) and shooting over and over again, sometimes until __4__.One day I asked her __5__ she practiced so much.She looked __6__ in my eyes and without a moment of hesitation she said, "I want to go to college. The only way I can __7__ is that if I get a scholarship, I am going to play college basketball.I want to be __8__.My Daddy told me if the dream is big enough, the facts don't count." Well, I had to give it in to her-she was __9__.One day in her senior year, I saw her sitting in the grass, head __10__ in her arms.I walked toward her and quietly asked what was __11__."Oh, nothing," came a soft reply."I'm just too short." The coach told her that at her height she would probably __12__ get to play for a top ranked team, __13__ offered a scholarship.So she __14__ stop dreaming about college. She was __15__ and I sensed her disappointment.I asked her if she had talked to her dad about it yet.She told me that her father said those coaches were wrong.They just didn't __16__ the power of a dream.He told her __17__ she really wanted to play for a good college, if she truly wanted a scholarship, __18__ could stop her except one thing-her own attitude.He told her again,"if the dream is big enough, the facts don't count." The next year, as she and her team went to the Northern California Championship Game, s  he was seen by a college recruiter (招聘人员). She was indeed offered a __19__.She was going to get the college education that she had __20__ and worked toward for all those years. | ||||
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