A:2.4 g金属镁变成镁离子时失去的电子数目为0.1NA
B:2 g氢气所含原子数目为NA
C:1 mol MgCl2固体溶于水中,所得氯离子的数目为NA
D:17 g氨气所含电子数目为10NA
In western countries, when your friend offers (提供 )you something, you can accept it directly(直接地), or refuse it politely. Therefore, which situation fits the western custom?
用计算器计算:-6.25+(-3.41)-31.7.