题干

标准状况下VL氨气溶解在1L水中(水的密度近似为1g/mL),所得溶液的密度为ρg/mL,质量分数为ω,物质的量浓度为c moL/L,则下列关系中不正确的是(溶质用NH3表示)( )

A:ρ='(17V+22400)/(22.4+22.4V)'

B:ω='17V/(17V+22400)'

C:c='1000Vρ/(17V+22400)'

D: ω=17c/(1000ρ)

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答案(点此获取答案解析)

A

同类题5

阅读下面短文,从短文后各题所给的四个选项(A、B、C、D)中,选出可以填入空白处的最佳选项。

    People from every corner flooded into the streets that Christmas Eve. “Frosty the Snowman,” and “Jingle Bells” 1 in stores; on the pavements, the street singers performed happily. Everyone, was2 by someone else, delighted and cheerful. I was alone.

    As one of 8 kids of a Brazilian family, brought up in America's crowded apartment, I'd spent several years searching for aloneness. Now, 3, at 27, a college student after the 4 with my girlfriend , every cell inside me wanted to be alone, 5 not at Christmas. My family had 6 to Brazil and my friends were 7 with their own lives. Dusk was approaching, and the fact that I had to return to my 8 home made me sad. Lights from windows blinked, and I hoped someone would 9 from one of those homes to invite me inside with a Christmas tree decorated with shiny fake snow and 10 presents.

    At a market, I felt more 11 when people were buying lots of goods, which 12 the gifts we received as children in my mind . I missed my family and wanted to cry for wanting to be alone and for having achieved it.

    Outside the church , a manger(小耶稣) had been set 13. I stood with others watching the scene, some of them 14themselves, praying. As I walked home, I realized that leaving Brazil was still a painful experience as I struggled with 15 I had become in 15 years in America. I'd mourned the 16, but for the first time, I recognized what I'd gained. I was independent, 17 and healthy. My life was still ahead, full of 18.

    Sometimes the best gift is the one that you give yourself. That Christmas, I gave myself 19 for what I'd obtained up to now and promise to go forward. It is the best gift I've ever got, the one that I most 20.