1
\(n_{Ba\left(OH\right)_2}=0,25.2=0,5\left(mol\right)\\ \Rightarrow m_{Ba\left(OH\right)_2}=0,5.171=85,5\left(g\right)\)
2
\(n_{FeCl_3}=0,08.0,15=0,012\left(mol\right)\\ \Rightarrow m_{FeCl_3}=0,012.162,5=1,95\left(g\right)\)
3
\(n_{MgSO_4}=4,5.0,8=3,6\left(mol\right)\\ \Rightarrow m_{MgSO_4}=3,6.120=432\left(g\right)\)
4
\(n_{Zn\left(NO_3\right)_2}=0,015.0,4=0,006\left(mol\right)\\ \Rightarrow m_{Zn\left(NO_3\right)_2}=0,006.189=1,134\left(g\right)\)