Răspuns:
ms=438g
C=25%
md=?
md=C x ms/100=25x438/100=109,5g HCl
MHCl=1+35,5=36,5g/mol
MCa=40g/mol
MH2=2x1=2g/mol
40g..2x36,5g................2g
Ca + 2HCl → CaCl2 + H2↑
xg......109,5g................yg
x=109,5x40/2x36,5=calculeaza
y=109,5x2/2x36,5=calculeaza
calculam numarul de moli
nHCl=m/M=438/36,5=12moli
2moli......1mol
Ca + 2HCl → CaCl2 + H2↑
12moli.....zmoli
z=12x1/2=6moli CaCl2
Explicație: