Mr(H3PO4) = 3Ar(H) + Ar(P) + 4Ar(O) = 3 x 1 + 31 + 4 x 16 = 98
w(P/H3PO4) = Ar(P)/Mr(H3PO4) x 100% = 31/98 x 100% = 31,63%
NaOH+Cu(NO3)2=NaNO3+Cu(OH)2
Находим массу серной кислоты
m(H2SO4)=200*50%/100%=100 г
100 g Xg
H2SO4+BaCL2-->BaSO4+2HCL
98 208
M(H2SO4)=98 g/mol M(BaCL2)=137+71=208 г/моль
100/98 = x/208
x=212.2g
m(прак) = 212.2*90%/100%=191g
ответ 191 г
3.
2.4g xL
C+O2=CO2
12g 22.4L
x=2.4·22.4/12=4.48L
4.
mZn=14.4·0.9=12.26g
12.26g xg
Zn+2HCl=ZnCl+H2
65g 2g
x=12.26·2/65=0.37g
v=0.37/2=0/18mol