Sodium carbonate is a reagent that may be used to standardize acids. In such a standardization it was found that a 0.498-g sample of sodium carbonate required 21.3 mL of a sulfuric acid solution to reach the endpoint for the reaction.

Na2CO3 (aq) + H2SO4 (aq) → H2O (l) + CO2 (g) + Na2SO4 (aq)

What is the molarity of the H2SO4?

The molarity of H2SO4 is 0.221 M

Explanation:

Step 1: Data given

Mass of sodium carbonate (Na2CO3) = 0.498 grams

Molar mass Na2CO3 = 105.99 g/mol

Volume of sulfuric acid (H2SO4) = 21.3 mL = 0.0213 L

Step 2: The balanced equation

Na2CO3 (aq) + H2SO4 (aq) → H2O (l) + CO2 (g) + Na2SO4 (aq)

Step 3: Calculate moles Na2CO3

Moles Na2CO3 = 0.498 grams / 105.99 g/mol

Moles Na2CO3 = 0.00470 moles

Step 4: Calculate moles H2SO4

For 1 mol Na2CO3 we need 1 mol H2SO4 to react and produce 1 mol H2O, 1 mol CO2 and 1 mol Na2SO4

For 0.00470 moles Na2CO3 we need 0.00470 moles H2SO4 to react

Step 5: Calculate molarity of H2SO4

Molarity H2SO4 =moles H2SO4 / volume

Molarity H2SO4 = 0.00470 / 0.0213 L

Molarity H2SO4 = 0.221 M

The molarity of H2SO4 is 0.221 M

a. energy is absorbed in the reaction.

if in a given reaction the energy of products is greater than the energy of reactants it means that reaction is endothermic and during the reaction, the energy is absorbed by reactants. in an endothermic reaction, the products have more stored chemical energy than the reactants. and in this reaction the reactants are more stable than products before the compounds with less energy are always more stable.