Răspuns:
B
n=15 moli H2O
MH2O=2×1+16=18g/mol
MNaOH=23+16+1=40g/mol
m=15×18=270gH2O
scriem reactia dintre Na si apa
2×18g 2×40g
2Na+2H2O→ 2NaOH + H2↑
270g ygNaOH
y=270×2×40/2×18=600g NaOH
C
MH2=2×1=2g/mol
MH2O=2×1+16=18g/mol
m=15×18=270gH2O
2×18g 2g
2Na+2H2O→ 2NaOH + H2↑
270g zg
z=270×2/2×18=15g H2
Explicație:
