Calculate the mass of sulfuric acid that you need to take to react with sodium hydroxide to get 14.2 g of salt.

Given:

m (Na2SO4) = 14.2 g

To find:

m (H2SO4) -?

Decision:

1) We compose the reaction equation corresponding to the condition of the problem:

H2SO4 + 2NaOH = Na2SO4 + 2H2O

2) Find the amount of sodium sulfate contained in 14.2 grams of the substance:

n (Na2SO4) = m: M = 14.2 g: 142 g / mol = 0.1 mol;

3) We compose a logical expression:

if 1 mol of H2SO4 gives 1 mol of Na2SO4,

then x mol H2SO4 will give 0.1 mol Na2SO4,

then x = 0.1 mol.

4) Find the mass of sulfuric acid required for the reaction to proceed:

m (H2SO4) = n * M = 0.1 mol * 98 g / mol = 9.8 g.

Answer: m (H2SO4) = 9.8 g.