Mass-Mass Relationships.

Question

-If sulfuric acid (H2SO4) reacts with 29 grams of sodium chloride (NaCl), how many grams of hydrochloric acid (HCl) are produced?

H2SO4 + NaCl ----> HCl + Na2SO4

-In the same reaction, how much salt (NaCl) is needed to produce 4.0 moles of sodium sulfate (Na2SO4)?

-In the same reaction, if you started with 100 moles of sulfuric acid (H2SO4), how many moles of hydrochloric acid (HCl) could you produce?

Answer 1

H₂SO₄ + 2NaCl ----> 2HCl + Na₂SO₄ ... balanced equation

molar mass NaCl = 58.4 g/mol

atomic mass Cl = 35.5 g/mol

molar mass HCl = 36.5 g/mol

29 g NaCl x 1 mol NaCl / 58.4 g x 2 mol HCl / 2 mol NaCl x 36.5 g HCl / mol HCl = 18.1 g HCl = 18 g HCl

This can also be done using % composition as follows:

%Cl in NaCl = 35.5 / 58.4 (X100%) = 60.8%

grams Cl = 60.8% x 29 g = 17.6 g Cl

%Cl in HCl = 35.5 / 36.5 (x100%) = 97.3%

0.973 x = 17.6 g

g HCl = 18 g HCl

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4.0 mol Na₂SO₄ x 2 mol NaCl / mol Na₂SO₄ x 58.4 g NaCl / mol NaCl = 467 g NaCl needed = 470 g NaCl

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100 mol H₂SO₄ x 2 mol HCl / 1 mol H₂SO₄ = 200 mols HCl