Stoichiometry of Reactions in Solution

Stoichiometric calculations involving solutions of specified molar concentration are usually quite simple since the number of moles of a reactant or product is simply volume × molar concentration.

Example 1

What volume of 1.40 M H₂SO₄ is needed to react exactly with 100 g of aluminum according to the Equation

First calculate the number of moles of Al, then moles of H₂SO₄ needed and then the volume of H₂SO₄

solution required:

Example 2

40.0 mL of an H₂SO₄ solution was titrated with 0.215 M NaOH. 35.26 mL of base was required to

exactly neutralize H₂SO₄. What was the concentration of the acid?

The titration reaction,

shows that 2 mol NaOH are needed to react with 1 mol H₂SO₄. Thus,