题目

一块表面已被氧化生成Na2O的金属钠,其质量为10.8 g，投入100 g水中，放出H2 0.2 g。请计算被氧化的钠的质量。 答案：解析： 2Na＋2H2O===2NaOH＋H2↑2×23                              2m(Na)                           0.2 gm(Na)==4.6 gm(Na2O)=10.8 g－4.6 g=6.2 g被氧化的钠的质量为：6.2 g×=4.6 g答案：4.6 gThe phrase "Made in China" has become ______ the same meaning for getting what you need on the cheap. A．somewhatB．somehowC．anyhowD．anyway