Question

Cantitatea de metal care se găseşte in 12,4 g oxid de sodiu este :

a) 0.4 moli Na
b) 0.2moli Na
c) 9.2 g Na

Answer 1

$\mathtt{M_{Na_2O}=23\cdot2+16=62g/mol}$

$\mathtt{62g \ Na_2O..........2\cdot23g \ Na}$

$\mathtt{12,4g \ Na_2O..........x \ g \ Na}$

$\mathtt{x=\frac{12,4\cdot2\cdot23}{62}=9,2g \ Na=0,4 \ moli \ Na(raspunsuri \ corecte:a,c)}$