(1)瓦斯中甲烷与氧气的体积比为1:2时极易发生爆炸,此时甲烷与氧气的质量比为______. (2)现有0.284kg质量分数为10%的Na 2 SO 4 溶液,则溶液中Na 2 SO 4 的物质的量为______. (3)配制250mL2.0mol/LH 2 SO 4 溶液,需要18mol/LH 2 SO 4 溶液的体积______mL.
【简答题】In this video clip, the speaker mentioned two theories about the use of grammar, what are they? Which theory do you think could be considered as a proof of the statement "Grammar does matter". Try to ...
【单选题】下面哪一项不是结构化程序设计的原则?Which of the following is not a principle of structured programming?a. 以自顶向下模块化的方式设计程序b. 用一系列控制结构来编写每个程序模块的代码c. 编写程序代码,使得不用测试就能正确运行d. 使用良好的程序设计风格