35g 43g Xg
Ca3(PO4)2+3H2SO4-->3CaSO4+2H3PO4
310 3*98 3*136
M(Ca3(PO4)2=310g/mol
M(H2SO4)=98g/mol
M(CaSO4)=136g/mol
n(Ca3(PO4)2)=m(Ca3(Po4)2)/M(Ca3(PO4)2)=35/310=0.113 mol
n(H2SO4)=m(H2SO4)/M(H2SO4)=43/98=0.439 mol
n(Ca3(PO4)2)35/310 = X/408
X=46.06 g
m(CaSO4 прак)=46.06*99%/100%=45.6g
ответ 45.6 г