Question

Calculeaza cantitatea de substanta si masa hidrogenului care se elimina la interactiunea a 36 g de apă cu: a) un metal monovalent b) un metal divalent

Answer 1

                       36 g      Xg            y g
           2 Na + 2H2O =2NaOH + H2                  MH2O=2+16=18
                        2.18g    2.40 g     2g                  MNaOH=23+16+1=40
                                                                          MH2=2

x=36.2.40:2.18=80 g NaOH

y=36.2:2.18=2 g H2



                   36g        a g             b g
          Ca +2 H2O =Ca(OH)2 +H2
                 2.18 g       74 g         2g

a=36.74:2.18=74 g b Ca (OH)2      
                                                                  MCa(OH)2=40+2.32+2=74
b=36.2:2.18=2g H2