What is the mass of 2.7 mol of lead nitrate Pb (NO3)?

Given:
n (Pb (NO3) 2) = 2.7 mol

To find:
m (Pb (NO3) 2) -?

Decision:
1) Using the periodic system of D.I.Mendeleev, calculate the molar mass of Pb (NO3) 2, which will be numerically equal to the molecular mass:
M (Pb (NO3) 2) = Mr (Pb (NO3) 2) = Ar (Pb) + Ar (N) * 2 + Ar (O) * 6 = 207 + 14 * 2 + 16 * 6 = 331 g / mole;
2) Calculate the mass of Pb (NO3) 2:
m (Pb (NO3) 2) = n (Pb (NO3) 2) * M (Pb (NO3) 2) = 2.7 * 331 = 893.7 g.

Answer: The mass of Pb (NO3) 2 is 893.7 g.