Question

Prin reatia a 50 g Magneziu de puritate=96% cu apa rezulta un amestec ce contine 90% apa. Calculati masa de apa folosita

Answer 1

m.ip = 50 g

p = 96%

p = m.px100/m.ip

=> m.p = 96X50/100 = 48 g

48 g........n g........... m g

Mg  +  2H2O  =>  Mg(OH)2 + H2

24........2x18................58

=> m = 48x58/24 = 116 g Mg(OH)2

100% - 90% apa = 10% Mg(OH)2

=> 100% amestec .......... 10% Mg(OH)2

  a g amestec.....................116 g Mg(OH)2

=> a = 116x100/10 = 1160 g amestec

=> 1160 - 116 = 1044 g apa ramasa

=> n = 48x2x18/24 = 72 g apa consumata

=> apa introdusa = apa totala + apa cons.

=> apa introd = 1044 + 72 = 1116 g apa