掌握化学用语是学好化学的基础.请用化学用语填空:
(1)单质铁____ ;
(2)3个碳原子____ ;
(3)5个水分子____ ;
(4)硫在空气中燃烧____ .
Now that you are a middle school student, you should learn to be _____ of your parents' help.
你会计算下面图形的面积吗?
配制2000g生理盐水(溶质质量分数为0.9%),需要称取NaCl的质量为( )