用化学符号表示3个水分子_____氖气_____2个氯离子____氯化钙中钙的化合价为_____2个氦原子____钡的氧
2个回答

3 H2O; Ne; 2 Cl-; +2; 2 He; BaO

(1)相对分子质量 = 12*28+1*44+1*16=396

(2)C:H:O = (12*28):(1*44):(1*16) = 84:11:4

(3)碳元素的质量 = 198 g × (12*28/396*100%) = 168 g

Na2SO4; 2 He; P4; H2; 5Cl-; Ca(正上方写+2); CO32-; OH-;

NO3-; NH4+