Calculate the mass of the salt that is formed by the interaction of 4 g of sodium hydroxide

Calculate the mass of the salt that is formed by the interaction of 4 g of sodium hydroxide with a solution of sulfuric xylote?

To make correct calculations, we write the reaction equation:

2NaOH + H2SO4 = Na2SO4 + 2H2O;

Further, according to the mass of NaOH specified in the condition, we find its amount mol (n):

n (NaOH) = m (NaOH): M (NaOH) = 4 g: 40 g / mol = 0.1 mol;

Coefficient 2 in front of NaOH indicates that the amount of its mol will be 2 times greater than that of salt (Na2SO4), based on the reaction equation. So n (Na2SO4) = n (NaOH): 2 = 0.1: 2 = 0.05 mol;

It remains only to find the mass of the salt itself:

m (Na2SO4) = n (Na2SO4) * M (Na2SO4) = 0.05 mol * 142 g / mol = 7.1 g.