a)

Ở 10^oC:

S_{MgCl_2}={m_{MgCl_2}}/{m_{H_2O}}.100=53,5(g)

->m_{MgCl_2}=0,535.m_{H_2O}

Mà m_{MgCl_2}+m_{H_2O}=614,4(g)

->m_{MgCl_2}\approx 214,14(g);m_{H_2O}\approx 400,26(g)

Ở 60^oC:

S_{MgCl_2}={m_{MgCl_2}}/{400,26}.100=61(g)

->m_{MgCl_2}=244,1586(g)

->m_{MgCl_2\ them}=244,1586-214,14=30,0186(g)

b)

Ở 60^oC:

Đặt n_{MgCl_{2}.6H_2O}=x(mol)

->n_{MgCl_2\ them}=x(mol);n_{H_2O\ them}=6x(mol)

->S_{MgCl_2}={214,14+95x}/{400,26+6x.18}.100=61

->x\approx 1,031(mol)

->m_{MgCl_{2}.6H_2O}=1,031.203=209,293(g)