Answer
The necessary mass is equal to 39.4g
Work Step by Step
1. Find the number of moles:
$Concentration(M) = \frac{n(mol)}{V(L)}$
$0.300 = \frac{n(mol)}{0.500}$
$0.300 * 0.500 = n(mol)$
$0.150 moles = n(mol)$
2. Determine the molar mass of this compound ($NiSO_4 + 6H_2O$):
58.69* 1 + 32.07* 1 + 16* 4 + 6 * ( 1.008* 2 + 16* 1 ) = 262.86g/mol
3. Calculate the mass
$mm(g/mol) = \frac{mass(g)}{n(mol)}$
$mm(g/mol) * n(mol) = mass(g)$
$ 262.86 * 0.150 = mass(g)$
$39.4 = mass(g)$
