How much carbon dioxide is formed by the interaction of sodium carbonate with 400 g of 37% hydrochloric acid solution?

1) We compose the reaction equation and arrange the coefficients:
Na2CO3 + 2HCl = 2NaCl + CO2 + H2O.
2) Find the mass of the solute of hydrochloric acid in its 37% solution:
37 = (x / 400) * 100%.
x = 148g.
3) We find the amount of hydrochloric acid substance by dividing the mass of the acid by its molar mass (molar mass is calculated according to the periodic table):
148 / (1 + 35.5) = 148 / 36.5 = 4 mol.
4) Consider the reaction equation. Two moles of hydrochloric acid account for one mole of carbon dioxide. Hence, we conclude that the amount of carbon dioxide substance is 2 mol.
Answer: 2 mol.