Verified Answer :

Willchemistry

Molar mass Mg(NO3)2 = 148.3 g/mol

1 mole ------------------- 148.3 g
0.12 moles -------------- ( mass )

mass = 0.12 x 148.3 / 1

mass = 17.796 / 1

= 17.796 g of Mg(NO3)2

hope this helps!

sortingsteering

Answer: 17.796 g

Explanation: Molar masses of the given elements:

mMg= 24.3 g/mol

mN=14 g/mol

mO=16 g/mol

molar mass of Mg(NO3)2:

mMg(NO3)2= 24.3+(14+316)2

mMg(NO3)2=148.3 g/mol

To calculate the mass of 0.12 mol of Mg(NO3)2 we multiply the molar mass by the number of moles:

mass=0.12mol*148.3 g/mol

mass=17.796 g