猜你喜欢
- 1my father is going on a ——.he is going to beijing
- 2为什么只说相对原子质量等于质子数加中子数而不说等于电子数加中子数呢?
- 3如图,在△ABC中,D是AB上一点,DF交AC于点E,DE=FE,AE=CE,AB与CF有什么位置关系?证明你的结论.
- 4一瓶装满水后为64g,装满煤油后56g,求瓶子的质量和容积
- 5用NA表示阿伏加德罗常数的值,下列说法中正确的是( ) A.2.4 g 金属镁变成镁离子时失去的电子数为0.1NA B.2 g 氢气中含有的分子数为NA C.3.01×1023 个氮分子中含有的原子数为2NA D.22.4L氨气
- 6已知偶函数f(x)在[0,+无穷]上是增函数,求不等式f(2x+1)
- 7已知B为NH4CL,且25摄氏度时,0.1mol/L B溶液的PH=a,则B溶液中c(H+)-c(NH3H2O)=?
- 8Last Saturday ,we had a class trip to Beijing Wildlife Park.We went there to watch birds .When we a____1___,the zookeepe
- 9『求助翻译』A good knowledge of English is necessary.
- 10It is a beautiful flower.怎样改成感叹句