2 phóng khí H2 VD2: Mg + 2HCl MgCl2 + H2 2H+ + 2e H2 nH2 n H 2 VD1: Na + H2O Ca + 2H2O 2H2O + 2e NaOH + ½H2 Ca(OH)2 + H2 2OH + H2 nH2 n OH A) Be, Ca, Ba C) Mg, Ca, Ba (a) Na + H2O (c) Be + H2O (e) Mg + H2SO4 B) Ca, Ba, Sr D) Mg, Ba, Sr (b) K + HCl (d) Mg + H2O (f) Ca + H2O 3 VD3: A Chú ý 2O K = 39; Rb = 85,5; Cs = 133; Be = 9; Mg = 24; Ca = 40; Sr = 87; Ba = 137 nM nH2 5, 22, M(OH)2 + H2 0, 25 (mol) MM mM nM 10 0, 25 40 M lµ Ca VD4: 2O Na + ½H2 Ba(OH)2 + H2 Ba + 2H2O nH n Na nH mBa nBa 6, 72 22, x x x 0, (mol) x 2nH2 0, (mol) 0,3 x 0, (mol) 27, (gam) (b) Có hai cách làm C1: nOH C2: VD5: A MCl2 + H2 nM nH2 0, 672 22, 0, 03 (mol) MM mM nM 1, 67 0, 03 55, 67 khí H2 A) Li B) Na C) K D) Rb A) 4,00 % C) % B) 2,194 % D) % 2 A) 120 gam C) 210 gam B) 110 gam D) 97,8 gam 2O thu A) Li B) Na C) K D) Rb A) Li, Na C) Na, K B) Li, K D) K, Rb A) Li, Na C) K, Rb B) Na, K D) Rb, Cs A nhóm IA A) 200 ml C) 300 ml B) 250 ml D) 350 ml B A) 9,4 B) 9,5 C) 9,6 D) 9,7 C A) 100 ml C) 300 ml B) 200 ml D) 600 ml D ãng, thu A) kali bari C) natri magie B) liti beri D) kali canxi E Hòa A) Mg Ca C) Mg Sr B) Be Mg D) Be Ca F H2SO4, A) 13,70 gam C) 18,46 gam B) 12,78 gam D) 14,62 gam G X 1,12 lít khí H2 A) Li B) Na < MY C) Rb D) K H 2SO4 A) Ba B) Ca C) Sr đro D) Mg Câu B Câu A C B C C B C D B C E D D F A C G C A H B B (a) 2Na + 2H2 2 (c) Be + H2 (d) Mg + H2O (e) Mg + H2SO4 (f) Ca + 2H2 Mg + H2O to to MgO + H2 + H2 + H2 MgO + H2