дано
m(Ba(OH)2) = 342 g
m(HCL) = 73 g
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m(BaCL2)-?
M(Ba(OH)2) = 171 g/mol
n(Ba(OH)2) = m/M = 342 / 171 = 2 mol
M(HCL) = 36.5 g/mol
n(HCL) = m/M = 73 / 36.5 = 2 mol
n(Ba(OH)2) = n(HCL) = 2 mol
BA(OH)2+2HCL --> BaCL2↓+2H2O
M(BaCL2) = 208 g/mol
n(Ba(OH)2) = n(BaCL2) = 2 mol
m(BaCL2) = n*M = 2*208 = 416 g
ответ 416 г