MgO was treated with 40 g of 20% HNO3 solution, what mass of salt was formed?

In the reaction of magnesium oxide with nitric acid, a salt is formed – magnesium nitrate.
MgO + 2HNO3 = Mg (NO3) 2 + H2O.
The mass of acid in solution is.
m (HNO3) = W (HNO3) • m (solution) / 100% = 20% • 40 g / 100% = 8 g.
The number of moles of nitric acid.
n (HNO3) = m / Mr = 8 g / 63 g / mol = 0.13 mol.
Taking into account the reaction coefficients, the amount of mol of salt.
n (Mg (NO3) 2) = 1 • 0.13 mol / 2 = 0.065 mol.
The mass of salt formed.
m (Mg (NO3) 2) = n • Mr = 0.065 mol • 148 g / mol = 9.62 g.