An excess of sodium hydroxide solution was added to 50 g of an 8% nitric acid solution. Calculate the mass of the salt formed.

We compose the equation of the ongoing reaction:
HNO3 + NaOH = NaNO3 + H2O.
1) Find the mass of the nitric acid solute. To do this, we multiply the mass of the acid solution by its mass fraction and divide by one hundred percent: 50 * 8/100 = 4g.
2) We calculate the molar mass of nitric acid according to the periodic table: 1 + 14 + 16 * 3 = 63.
3) Find the amount of nitric acid substance. For this, the mass of the solute of the acid is divided by its molar mass: 4/63 = 0.06 mol.
4) According to the reaction equation, there is one mole of sodium nitrate for one mole of nitric acid. This means that the amount of sodium nitrate substance is 0.06 mol.
5) The mass of salt is: 0.06 * 85 = 5.1 g – the answer.